Thermal treatment impact on the evolution of active phases in layered double hydroxide-based ZnCr photocatalysts: Photodegradation and antibacterial performance
-
Djurdjica Karanovic
,
Tatjana Vulic
Abstract
This study investigated the influence of thermal treatment on the photocatalytic performance of ZnCr layered double hydroxide-based mixed metal oxides in the degradation of methylene blue and brilliant cresyl blue organic dyes under simulated solar light irradiation. The photocatalysts were synthesized using a simple coprecipitation method and subjected to thermal treatment at temperatures ranging from 100°C to 900°C. Additionally, the study explored the antibacterial activity against Escherichia coli and Staphylococcus aureus using a novel antibacterial experimental setup. It not only involved the introduction of ZnCr samples into BioPeptone/prepared cell suspension to enhance photocatalyst–bacteria cell contact but also included research on antibacterial activity induced by solar irradiation and also in the absence of light, providing crucial insights into photocatalytic antibacterial activity of ZnCr photocatalysts. Despite satisfactory efficiencies observed for all thermally treated ZnCr samples (removal efficiency ranging from 40% to 90%), ZnCr 900 (thermally treated at 900°C) exhibited exceptional performance, achieving nearly 100% removal efficiency and complete growth inhibition for both bacteria. Integrating these findings with structural and textural characterization data, as well as kinetic studies, our comprehensive analysis enhances the understanding of structure-dependent photocatalytic activities. These insights open possibilities for the application of ZnCr photocatalysts in water purification and environmental remediation.
1 Introduction
Over the past few decades, the large-scale discharge of various organic and inorganic pollutants into the wastewater has raised significant concerns due to their adverse impact on water eco-systems [1,2]. The development of modern textile industry has contributed to the pollution of around 15% of water streams with effluent dyes from this industry [3]. Removal of organic dyes emerged as a matter of high importance due to their toxic and carcinogenic properties, which pose a serious threat to water eco-systems [4,5,6]. Azo dyes, which include compounds such as methylene blue (MB) and brilliant cresyl blue (BCB), constitute the largest group of textile dyes, comprising over 60% of the total dye pollutants released into water eco-systems [7,8,9]. Azo dyes have toxic, cancerogenic, and bio-accumulative nature and are extremely harmful to aquatic eco-systems and human health if discharged into the environment without previous treatment [7,10,11]. Furthermore, bacterial pollution of wastewater is another emerging environmental problem that represents a serious hazard to human health, as pathogenic bacteria not only exhibit toxicity to humans but also show resistance to antibiotics, requiring their removal from wastewater [12,13,14].
In the pursuit of the most effective method for wastewater purification, several factors should be considered: efficiency of the pollutant treatment process, microbial removal efficiency, simplicity, and long-term costs. Due to high stability and persistency of dye compounds, various purification methods for wastewater treatment have been researched over the past few decades, including adsorption, biodegradation, heterogeneous photocatalysis, ion-exchange, etc. [15,16,17]. Compared to other purification methods that merely concentrate pollutants (adsorption, ion-exchange), environmentally friendly photocatalytic processes have advantages since they are activated by free, abundant solar radiation and lead to complete demineralization of pollutants [18,19]. Advanced photocatalytic oxidation processes based on metal oxides as photocatalysts, coupled with the use of highly reactive radicals induced by solar light in situ, enable the development of cost-effective processes capable of decomposing resistant water pollutants [20,21]. Moreover, recent studies on photocatalytic processes have shown great potential for antimicrobial wastewater treatment [12,13,22].
Efficiency studies of several well-known semiconductors, such as TiO2, Bi2WO6 and SrTiO3, have been excessive. Additionally, metal oxides like ZnO [23,24,25], CuO [26], and Cr2O3 [27] have shown promising additional functional properties, which include photoinduced antibacterial activity, enhancing their potential for use in water purification treatments [20,28,29,30,31]. Currently, there is ongoing research focused on developing novel materials capable of overcoming the limitations of the aforementioned semiconductors, such as their relatively low charge separation and narrow light absorption spectra. For instance, Kumar et al. [32] demonstrated that Bi2WO6–TiO2 (20% mass)–Ti3C2 (5 mass%) nanocomposite degraded 98.5% of methyl green after 40 min of sunlight irradiation, outperforming TiO2, which achieved 74% efficiency after 80 min. Additionally, Sharma et al. [33] found that ciprofloxacin could be efficiently removed (77% in 160 min) under solar irradiation with novel ternary nanocomposites obtained from coupling Bi2WO6, ZnO, and Ti3C2 nanosheets. Lately, noble metal nanoparticles have emerged as potential doping agents for photocatalysts due to their unique properties. Mohanty et al. [34] reported that the heterojunction effect created after Au decoration of SrTiO3 and combined with Ti3C2 into a ternary interfacial heterostructure led to improved photocatalytic removal of ciprofloxacin (63% in 120 min). Interestingly, Choudhary et al. [35] determined that heterojunctions formed after combining CoFe2O4 with ZnO notably increased photocatalytic efficiency in MB removal (90.8% in 28 min) compared to pristine CoFe2O4 nanostructures (65% in 28 min). Also, Choudhary et al. [36] reported that optimal doping (0.5%) of Ce on ZnO nanowires significantly enhanced light utilization capability in visible spectral region due to reduced band gap of ZnO, which led to an increase of 20% in photocatalytic MB removal.
Layered double hydroxide (LDH) materials have emerged as promising photocatalysts for wastewater purification, given their reported ability to degrade various dyes [2], pesticides [37], and antibiotics [38]. Furthermore, these materials have exhibited antibacterial activity, which has been reported in numerous studies. Balcik et al. [39] reported that nanocomposite membranes incorporated with ZnFeCe LDH improved the bactericidal effect on Escherichia coli when compared to membranes without LDH. Additionally, Cardinale et al. [40] reported that a 150 mg disk of ZnAl-SO4 LDH had a 1.95 cm inhibition zone against E. coli.
LDHs have the following general formula:
Various studies on ZnCr LDH and its derived MOs have been conducted in the last decade. Mohaptra and Parida [2] demonstrated that ZnCr LDH successfully photodegraded 100% of rhodamine B and rhodamine 6G after 120 min of visible light irradiation. El Mersly et al. [55] studied the effect of different anions (
In light of specific requirements for inducing both photocatalytic and antibacterial properties, in this study, zinc (Zn) and chromium (Cr) were selected as constituent metals for the synthesis of LDHs. A simple and inexpensive low supersaturation coprecipitation method with carbonates as interlayer anions was selected for the synthesis of LDHs since it facilitates the formation of precipitates with a large number of low crystalline particles that, after thermal treatment, enables the formation of active MO phases. This research aims to investigate the influence of thermal treatment on ZnCr LDH-based materials and their photocatalytic behaviour, particularly in the degradation of selected organic dyes (MB and BCB). Moreover, standard Gram-negative (E. coli) and Gram-positive (S. aureus) model bacteria representatives were chosen for preliminary evaluation of antibacterial activity. While the existing literature has explored various aspects of BCB dye photodegradation [9,58,59], this research presents a novel approach by introducing ZnCr LDH-based mixed metal oxides as potential photocatalysts for degrading brilliant cresyl blue. Furthermore, the study introduces a novel antibacterial experimental setup aimed at not only enhancing photocatalyst–bacteria cell contact but also includes research on antibacterial activity induced by solar irradiation and also in the absence of light, thereby providing valuable insights into the photocatalytic antibacterial mechanism. By addressing these specific gaps in the literature, this study offers additional contributions to the field of photocatalysis and antibacterial materials.
2 Materials and methods
2.1 Sample preparation
Taking into consideration our previous experience and literature references [15,17,21,22,41,49,60–62,64], the parameters of the low supersaturation coprecipitation method at constant pH for the synthesis of ZnCr LDHs were selected. The precursor solution (70 mol% of Zn(NO3)2·6H2O and 30 mol% of Cr(NO3)3·6H2O) was added continuously (4 cm3·min−1) and stirred vigorously, along with the base solution (0.67 M Na2CO3; 2.25 M NaOH) that was used to maintain constant pH (9.4) at constant temperature (40°C). The molar ratio of constituent metals (Zn and Cr) was selected in order to enable the formation of photocatalytic active phases (value of x = Cr3+/(Zn2++ Cr3+) = 0.3 in the optimal range for the synthesis of single ZnCr LDH phase) that, after thermal treatment, facilitates the formation of active ZnO phase and the spinel phase, thereby avoiding the formation of additional unfavourable phases, such as Cr2O3 phase and Zn(OH)2, which are not photocatalytically active [50].
Precipitation products were aged 12 h under the same conditions, washed with distilled water until pH = 7, and dried (24 h; 100°C in the air) and thermally treated at different temperatures (300°C, 500°C, 700°C, 900°C) for 5 h in air. To induce the formation of active phases, the temperatures for sample thermal treatment were selected considering the temperatures of the following thermal decomposition steps: (1) dehydration of LDHs (loss of the physisorbed and interlayer water) in the temperature range of 100–250°C; (2) dihydroxylation (loss of hydroxyl groups from the brucite-like layer) in the temperature range of 350–450°C; (3) decarbonation (collapse of the layered structure and formation of nonstoichiometric MO phases) in the temperature range of 420–470°C; and (4) formation of stoichiometric spinel oxides and bivalent oxides in the temperature range of 600–800°C [62,63]. The obtained samples were denoted as follows: ZnCr 100, ZnCr 300, ZnCr 500, ZnCr 700, and ZnCr 900.
2.2 Characterization
Crystalline phases were identified by X-ray powder diffraction (XRD) using Rigaku MiniFlex 600 diffractometer (CuKα radiation, λ = 0.15406 nm; 2θ 10–70°; scan rate = 0.02 s−1). Scherrer formula (Eq. 1) and full width at half-maximum (FWHM) of intense diffraction peaks were used in order to calculate the crystallite size (CS):
where D is the CS (nm), k is the shape function (0.9), λ is the X-ray wavelength, θ is the angle of diffraction, and β is the FWHM of the considered peak.
The lattice parameters were calculated for the dominant phase detected by XRD analysis. The unit cell parameters a (width of the crystal unit cell – cation–cation distance in Brucite-like sheets) (Eq. 2), c (height of the crystal unit cell) (Eq. 3) and c′ (brucite-like sheet thickness) (Eq. 4) for the LDH phase were calculated from the positions of (110) and (003) reflections:
For the MO, a hexagonal zincite structure of ZnO, and the unit cell parameters a (width of the crystal unit cell) (Eq. 5) and c (height of the crystal unit cell) (Eq. 6) were calculated as [65,66]:
The texture of all samples was analysed by low-temperature nitrogen adsorption at –196°C (Microtrac Belsorp Max II). The specific surface area was calculated by the Brunauer–Emmer–Teller (BET) method. The pore size distribution and cumulative pore volume were determined by the Brunauer–Joyner–Hallenda (BJH) method applied to the desorption branch of the isotherm. The absence of micropores in samples was confirmed using the t-plot method.
Zeta-potential measurements were performed by dynamic light scattering using a Malvern Instrument, model Nano ZS. The refraction index of the investigated dispersions for ZnCr-LDHs was n = 1.22 and that for MB and BCB solutions was 1.34, while the refraction index of the dispersant (demineralized water) was n 0 = 1.33. The light absorption α was 0.2. The mean zeta potential values were obtained as the average value after performing 12 scans.
2.3 Photocatalytic experiments
All photocatalytic experiments were performed in an open Pyrex vessel using Osram Ultra Vitalux 300 W lamp (I (VIS) = 20.52 W·m−2; I (UVA) = 17.6 W·m−2) with the emission spectrum that simulates solar light positioned 45 cm above the top surface of each dye solution. The photocatalytic efficiency of all prepared samples was analysed by monitoring the photodegradation of two dye pollutants: MB and BCB. The suspensions were exposed to air without additional aeration throughout the duration of the ongoing experiment. Prior to each photocatalytic test, the reaction mixtures containing 50 mg of photocatalysts and 100 mL of dye solution (C MB = 10 mg·L−1 and C BCB = 10 mg·L−1) were stirred in the dark for 30 min in order to establish the required adsorption/desorption equilibrium between the dye and the catalyst surface. When the equilibrium was achieved, reaction mixtures were irradiated by light, and aliquots were taken and analyzed at defined time intervals using a UV-VIS spectrophotometer (EVOLUTION 600 spectrophotometer) at maximum absorption wavelengths (λ MB = 664 nm and λ BCB = 622 nm).
The MB/BCB photodegradation efficiency, E ff (%), was calculated as follows (Eq. 7):
where C 0 (mg·L−1) is the initial dye concentration and C t (mg·L−1) is the concentration at the defined time, t [67].
In order to exclude the influence of catalyst dosage and pollutant concentration on the photocatalytic degradation efficiency, degradation turnover (dTON) was calculated as follows [68,69]:
where C 0 and C f (μmol·L−1) are the initial and final concentrations of the dye, t (h) is the time, and M (g·L−1) is the catalyst dosage.
2.4 Kinetics of the photocatalytic reaction and artificial neural network (ANN)
The kinetics of organic dye photodegradation were calculated using the pseudo-first-order reaction rate (Eq. 8) that followed the Langmuir–Hinshelwood kinetic model:
where k app (min−1) is the apparent pseudo-first-order reaction constant, which was obtained from the slope of the ln(C 0 /C) vs time linear function.
The reaction half-time (Eq. 9), which represented the time required for the initial concentration of dye to reduce by half, was calculated as follows:
The electrical energy per order, E EO (kW·h·L−1·order−1), is a scale-up parameter used for the comparison of different photocatalytic water systems. This parameter provides information on the necessary electrical energy for the 90% order-of-magnitude pollutant degradation in a studied volume of polluted water [69,70]:
where P (kW) represents the electric lamp power and V (L) is the volume of the reaction mixture [69].
A predictive model for the photocatalytic behaviour of thermally treated ZnCr samples in the photodegradation of two organic dye pollutants was proposed. The created ANN for the photodegradation rate constant consisted of four inputs from experimental variables: the thermal treatment temperature (TTT), organic dye type (ODT), CS, and pore diameter of the most present pores (MPPD). A limited-memory Broyden–Fletcher–Goldfarb–Shanno optimization algorithm was used in the solver function of the neural network, with the number of iterations limited to 100. In order to optimize the network training speed, the early stopping function was enabled after ten iterations with no improvements in the validation of data sets. For this type of data modelling, it is crucial to determine the right number of neurons in the hidden layer, and the trial and error method showed that the number of ten neurons in the hidden layer works best in this ANN. It was estimated that the optimal function for connecting input neurons to hidden neurons was hyperbolic tangent sigmoid (tansig). The ANN predictive model simulations were carried out using Python 3.
2.5 Antibacterial experiments
In order to assess the antibacterial activity of the samples, microbiological experiments were performed on both Gram-negative (E. coli ATCC 25922) and Gram-positive (S. aureus ATCC 25923) bacteria [30,71]. Prior to microbiological analysis, both cultures were grown on plate count agar at 37°C for 24 h. Then, the cultures were suspended in 9 cm3 of BioPeptone (HiMedia, Mumbai, India), corresponding to McFarland density number 5 (approximately 1.5 × 109 CFU cm−3). The prepared ZnCr samples (50 mg) were suspended in 100 cm3 of BioPeptone, and 1 cm3 of freshly prepared cell suspensions was added to obtain the final cell concentration of 6–7 log CFU·mL−1. In order to pinpoint and distinguish solely photocatalytic antibacterial activity of photocatalysts, an additional novel setup was introduced. The antibacterial effect of each sample was tested not only for solar irradiation (Osram Ultra Vitalux 300 W lamp) but also in the dark, without light irradiation. For better dispersion of photocatalysts, all investigated samples were stirred vigorously in the suspension. Control samples containing only BioPeptone with 1 cm3 of the same cell suspension, without photocatalysts, were subjected to the same conditions. In order to track the antimicrobial effect of ZnCr samples, an aliquot of 1 cm3 was sampled at defined time intervals (0, 3, and 6 h), and serial dilution was prepared and transferred onto adequate selective solid media: tryptone bile X-glucuronide agar for E. coli and Baird–Parker agar for S. aureus. After the incubation period (37°C, 24 h), the grown colonies were counted.
3 Results and discussion
3.1 Structural characterization
The phase composition of all synthesized samples was determined from the XRD spectra (Figure 1). The wide, low-intensity diffraction peaks of ZnCr 100 sample positioned at 2θ values of 11.96°, 23.78°, 34.21°, and 59.79° were assigned to the (003), (006), (012), and (110) reflection planes of ZnCr LDH (JCPDS card no. 51-1525) [57,72,73].
XRD patterns of the synthesized samples: ZnCr 100, ZnCr 300, ZnCr 500, ZnCr 700, and ZnCr 900.
These characteristic reflections of the dried ZnCr 100 sample confirmed the layered structure with R3m rhombohedral symmetry, which is expected for LDHs synthesized with nitrate precursors [74]. The structure of the synthesized sample and the lattice parameters of ZnCr 100 were defined for the dominant LDH phase and the evaluated unit cell parameters are presented in Table 1.
Structural and textural parameters of the obtained samples
| Sample | ZnCr 100 | ZnCr 300 | ZnCr 500 | ZnCr 700 | ZnCr 900 |
|---|---|---|---|---|---|
| a (nm) | 0.308 | 0.299 | 0.325 | 0.325 | 0.298 |
| c (nm) | 2.218 | 0.561 | 0.521 | 0.522 | 0.562 |
| c/a | 7.2 | 1.88 | 1.60 | 1.61 | 1.89 |
| D (nm) | 4.21 | 8.35 | 17.71 | 28.99 | 39.68 |
| S BET (m2·g−1) | 116.8 | 27.6 | 25.3 | 16.1 | 4.6 |
| S t-plot (m2·g−1) | 117.4 | 27.6 | 25 | 15.1 | 4.05 |
| V p (m3·g−1) | 0.19 | 0.23 | 0.23 | 0.23 | 0.04 |
| d p (nm) | 4 | 35 | 35 | 65 | ∼100 |
The calculated values of the structural lattice parameters a and c were consistent with those reported in the literature [50,51]. The c′ value (d 003), which described the thickness of one layer consisting of a Brucite-like sheet and one interlayer, was also calculated and compared with d 006. Considering that d 003 (0.74 nm) was twice as high as d 006 (0.37 nm), favourable stacking of layers can be suggested for the ZnCr 100 sample [15,75].
The XRD analysis of ZnCr 300, ZnCr 500, ZnCr 700, and ZnCr 900 samples confirmed the formation of MOs, attributed to the degradation, dihydroxylation, and decarbonation during thermal treatment leading to the collapse of layered structure. All thermally treated samples exhibited reflections at 2θ values of 31.8°, 34.4°, 36.2°, 47.5°, 56.6°, 63.05°, 66.3°, 67.9°, and 69.1°, assigned to (100), (002), (101), (002), (110), (103), (200), (112), and (201) reflection planes of the zincite ZnO phase (JCPDS card no.36-1451), respectively, as the dominant phase in all samples. Additionally, the thermal treatment of samples at 300°C and above induced the formation of the ZnCr2O4 spinel phase (JCPDS card no. 73-1962), evidenced by reflections at 30.3°, 35.6°, 43.3°, 53.8°, 57.5° corresponding to (220), (311), (400), (422), and (511) reflection planes [76]. The lower intensity of these reflection peaks suggested lower crystallinity and lower ZnCr2O4 phase amount. As TTT increased, XRD reflections became more intense, indicating enhanced crystallinity of phases [74,77]. The axial c/a ratio for ZnCr 500 and ZnCr 700 was around 1.6, indicative of a close-packed hexagonal (wurtzite) structure of ZnO [66]. Deviations from this value in ZnCr 300 and ZnCr 900 samples were observed. The ZnCr 300 sample exhibited low-intensity peaks, suggesting that the formation of low crystalline, meta-stable, nonstoichiometric MOs [49] could explain the deviation. On the other hand, the presence of intense, sharp peaks in the ZnCr 900 sample indicated a higher ZnCr2O4 phase amount, explaining the deviation for this sample. The crystallite size D also increased with temperature, indicating that crystallinity can be improved and controlled with the temperature [66].
The structural analysis results indicated that the chosen molar ratio initiated the formation of a layered structure for the sample ZnCr 100 [78]. Furthermore, after thermal treatment, the formation of ZnO and ZnCr2O4 phases was observed, aimed at enhancing photocatalytic efficiency through synergistic and heterojunction effects [50].
3.2 Textural characterization
The adsorption isotherms and pore size distribution, as well as textural parameters of all studied samples (specific surface area (S BET), pore volume (V p), and the most present pore diameter obtained from BJH pore size distribution (d p)), are presented in Figure 2 and Table 1. Notably, all samples, except ZnCr 100, exhibited similar adsorption isotherms. ZnCr 100 displayed a type IV adsorption isotherm (Figure 2a) with an H2 hysteresis loop type, indicating a mesoporous structure with ink bottle-shaped pores [79]. Furthermore, this sample showed a monomodal pore size distribution (Figure 2b) with one intense peak at ∼4 nm, suggesting a higher presence of smaller mesopores, developed BET surface area (Table 1), and a small value of the calculated average pore diameter.
Textural analysis results: (a) adsorption/desorption isotherm and (b) pore size distribution (adsorptive N2, −196°C).
Upon calcination at temperatures of 300°C and higher, samples ZnCr 300, ZnCr 500, ZnCr 700, and ZnCr 900 showed a type II isotherm. Type II isotherm is characteristic of the non-porous or macroporous materials that exhibit unrestricted monolayer/multilayer adsorption. The isotherms of thermally treated samples displayed an H3 hysteresis loop type, indicating a mesoporous structure with wedge-shaped pores formed by the loose stacking of flaky particles [79]. However, the hysteresis loop for ZnCr 300 began forming at a relative pressure of 0.4, suggesting non-uniformed pores in this sample [17].
Pore size distribution for ZnCr 300 revealed a low-intensity peak at around 4 nm (similar to the ZnCr 100 sample) and a broad peak at larger pore diameters (20–60 nm). These results suggest incomplete LDH thermal decomposition at the lowest TTT of 300°C. As the TTT increased, smaller mesopores completely disappeared, and the pore size distribution shifted towards larger values of pore diameters, consistent with the decrease in the BET surface area of these samples.
The difference in the adsorption/desorption isotherm of the sample ZnCr 100 compared to thermally treated samples can be attributed to its layered structure, which disappeared at higher temperatures of thermal treatment. The collapse of the layered structure caused changes in the pore type (transformation from ink-bottle pores to wedge-shaped pores) and size (disappearance of smaller pores), affecting N2 gas adsorption [56]. During thermal treatment at 300°C, dihydroxylation occurred, and the spinel MO phase was formed, as confirmed by XRD analysis. With increasing temperature, the crystallinity of the spinel phase also increased, leading to a decrease in the BET surface area [80].
The results obtained from the t-plot are also provided in Table 1, offering better insight into the pore structure [81]. The calculated external surface area from the t-plot (S tplot) and the calculated BET surface area were similar, indicating that the surface area originated solely from the presence of mesopores. These results also confirmed the absence of micropores in all samples.
3.3 Photocatalytic experiments
Photocatalytic experiments were conducted using MB and BCB dye pollutants. In order to rule out possible direct photolysis of dyes when irradiated, test solutions of both pollutants (MB and BCB) without a photocatalyst were treated under the same conditions as photocatalytic mixtures, and their concentration was measured with time. After 120 min, no photolysis was observed, suggesting that the organic dye pollutants used in these experiments were photochemically stable and the photocatalytic reaction was solely responsible for the dye degradation [55].
It was observed that the photocatalytic efficiency for the MB removal (Figure 3a) increased with the temperature of thermal treatment. After 9 h of irradiation, the removal efficiency for ZnCr 300 and ZnCr 500 was approximately 40%, while a high removal efficiency (85%) was detected for the ZnCr 700 sample. However, complete MB decolourization was achieved after only 4 h for the ZnCr 900 sample. The superior efficiency of the ZnCr 900 sample could be attributed to its favourable phase composition, particularly the amount and heterojunctions between photocatalytic active phases (ZnO and ZnCr2O4). In contrast, ZnCr 100 exhibited negligible MB photodegradation efficiency, likely due to its unsuitable phase composition (low crystalline LDH phase).
![Figure 3
Photodegradation efficiency of (a) MB and (b) BCB removal (Experimental conditions: catalyst amount = 50 mg, [MB] = [BCB] = 10 mg·L−1, I (VIS) = 20.52 W·m−2; I (UVA) = 17.6 W·m−2).](/document/doi/10.1515/gps-2023-0269/asset/graphic/j_gps-2023-0269_fig_003.jpg)
Photodegradation efficiency of (a) MB and (b) BCB removal (Experimental conditions: catalyst amount = 50 mg, [MB] = [BCB] = 10 mg·L−1, I (VIS) = 20.52 W·m−2; I (UVA) = 17.6 W·m−2).
Subsequent investigation of BCB photodegradation efficiency (Figure 3b) revealed high removal efficiency ranging from 70% to 90% for all thermally treated samples, with ZnCr 900 exhibiting the highest efficiency. As expected, ZnCr 100 showed moderate BCB removal efficiency (10%). The favourable phase composition, as explained for MB removal, also contributed to the enhanced BCB photodegradation of thermally treated samples.
All of the thermally treated samples exhibited significant capability for the removal of both dye pollutants, with efficiencies ranging from approximately 40% to 100%. It can be concluded that the temperature of the thermal treatment had a significant impact on photocatalytic degradation efficiency by triggering the formation of photocatalytic active phases responsible for the dye removal reactions.
The differences in the photodegradation efficiency between BCB and MB removal could be attributed to a combination of factors related to the chemical structure of the dyes, impacting adsorption affinity, interaction with photocatalysts, and formation of intermediates during the photocatalytic reaction. Although both MB and BCB are azo dyes, BCB possesses a complex heterocyclic structure containing a central thiazine ring with various substituents [59,82], whereas MB has a simpler structure of a central thiazine ring with methyl groups as substituents [83].
Considering all the above factors, an overall potential photocatalytic degradation mechanism can be proposed regarding both dyes [69,84]:
When in contact with the surface of the ZnCr photocatalysts, MB and BCB molecules were adsorbed due to the interactions between dye molecules and active sites on the photocatalytic surface. Upon solar irradiation, the photocatalysts generated electron–hole pairs (Eq. 12) that participated in the redox reactions: (i) photogenerated hole (h+) reacted with the chemisorbed dye molecules, leading to the oxidation of dyes and forming cationic radical cations (Eq. 13), and other intermediate products, and (ii) photogenerated electrons (e−) reduced oxygen (Eq. 14) or other remaining species producing reactive oxygen species (ROS) [83,69]. Intermediate products, formed during oxidation and reduction, underwent further degradation, producing simpler and less harmful products (Eqs. (15)–(17)). In summary, the overall photocatalytic efficiency depends on a complex relationship of various factors: the chemical nature of the dyes, properties of the obtained photocatalysts, solar absorption, and charge separation [84].
A comparative table of results from numerous studies on photocatalytic dye degradation using various semiconductor photocatalysts is presented in Table 2. When compared to similar work in recent years, the results presented in our studies reveal that the application of ZnCr-LDH-based catalysts positively influences the photocatalytic performance in the photodegradation process.
Comparison of the photocatalytic dye degradation efficiency of ZnCr 900 with the other published results
| Catalyst | Synthesis | Cat. conc (g·L−1) | Light source | Dye | Dye conc (mg·L−1) | Duration, min | Efficiency (%) | Ref. |
|---|---|---|---|---|---|---|---|---|
| ZnO-NPa | Coprecipitation | 0.01 | Sunlight | RRc | 5 | 100 | 88 | [85] |
| 0.02 | 95 | |||||||
| Ag-doped ZnO | Modified coprecipitation | 0.02 | Halogen lamp | MB | 10 | 80 | 93 | [86] |
| ZnCoFe LDH | Coprecipitation | 0.1 | LED light | MB | 10 | 180 | 47 | [69] |
| NiAl LDH | Coprecipitation | 0.01 | Visible light | BCB | 11.6 | 170 | 20 | [51] |
| CdO/ZnFe2O4 NCb | Sonication/precipitation/thermal treatment | 0.01 | Tungsten halogen lamp | MB | 25 | 160 | 79.1 | [29] |
| ZnCr LDH | Coprecipitation | 0.40 | Ultra-Vitalux lamp | MOd | 50 | 180 | 90 | [55] |
| ZnAl-NPa | — | 1 | Visible light | BCB | 40 | 180 | 86.7 | [87] |
| Cr doped ZnO-NPa | Hydrothermal | 0.01 | Natural sunlight | MB | — | 120 | 52.23 | [88] |
| ZnO NCCb | Chemical precipitation | 0.01 | Mercury lamp | MB | 10 | 20 | 60 | [89] |
| Sr-doped ZnO NPa | Mechanical milling method | 0.01 | Xenon lamp | MB | 10 | 30 | 53 | [90] |
| ZnCr LDH-based photocatalysts | Coprecipitation | 0.05 | Osram Ultra Vitalux 300 W lamp | MB | 10 | 200 | 100 | Present work |
| ZnCr LDH-based photocatalysts | Coprecipitation | 0.05 | Osram Ultra Vitalux 300 W lamp | BCB | 10 | 400 | 90 | Present work |
aNP – nanoparticles. bNCC – nanoclusters. cReactive-red-114. dMethyl Orange.
The differences in the photodegradation efficiency of ZnCr 900 between MB and BCB removal could be elucidated by the surface charge of both the dye molecules and the photocatalyst. The pH-dependent changes in surface charge can influence the adsorption affinity of MB and BCB onto the photocatalyst surface. The surface charge of the photocatalyst can vary with pH due to alterations in protonation and deprotonation of the surface functional groups. The pK a and pH values of MB and BCB dye solutions and reaction mixtures are provided in Table 3. The pH value (6.08) of MB exceeded its pK a value (3.8), rendering the solution more alkaline than the solute’s pK a. Consequently, the MB solute contains basic functional groups capable of accepting protons, resulting in proton loss (H⁺ ion) and increased negative charge. On the contrary, the pH value of the BCB solution (4.6) was lower than its pK a (6), resulting in a positively charged surface due to acidic functional groups capable of donating protons. The interaction between the photocatalysts and the dye solution resulted in an increase in pH values for both dyes. Introducing the catalyst into the MB solution amplified the difference between the pK a value and pH value, enhancing the negative surface charge. In the case of positively charged BCB dye molecules, the introduction of the photocatalysts neutralized the positive charge, as the difference between the pK a value (6) and pH value (6.03) was negligible. The photocatalytic reaction initiated a significant elevation of pH values in both reaction mixtures, reaching an alkaline pH after the reaction. It can be concluded that a more alkaline pH of the MB solution (8.1) enhanced and strengthened the electrostatic attraction between MB and ZnCr 900, leading to stronger adsorption and higher photocatalytic activity compared to BCB, which had almost a neutral pH value (7.5).
Zeta potential, pK a, pH values of MB and BCB dye solutions and reaction mixtures
| Dye | pK a | pH pristine | pH0 a | pHt b | Zeta potential (mV) |
|---|---|---|---|---|---|
| MB | 3.8 | 6.1 | 6.96 | 8.1 | −21.6 |
| BCB | 6 | 4.6 | 6.03 | 7.5 | −19.7 |
aInitial pH of the reaction mixture. bpH of the reaction mixture after 600 min.
Furthermore, the zeta potential (Table 3), used to measure the surface charge, additionally explained the magnitude of the electrostatic catalyst–dye interactions, considering that higher positive or negative zeta potential magnitude points to stronger repulsion or attraction [91]. The measured zeta potential of ZnCr 900 was positive (12.2 mV), indicating a slightly positive surface charge under neutral pH conditions. The positive zeta potential of the ZnCr photocatalyst, combined with the negative zeta potential of both MB and BCB dyes, demonstrated strong electrostatic attraction between the photocatalyst and dye molecules, which is favourable for higher adsorption and potentially higher photocatalytic activity [92]. Comparatively, a higher photocatalyst/MB zeta potential magnitude could better explain the photocatalytic behaviour in MB photodegradation. Overall, the combination of pH-dependent changes in surface charge and the positive zeta potential of ZnCr 900 induced higher adsorption affinity, formation of surface reactive sites, and, consequently, higher photocatalytic MB degradation. A higher value of the photodegradation process turnover parameter, dTON, for MB (15.5 μmol·h−1·g−1), compared to BCB (6.7 μmol·h−1·g−1), additionally supports the previous observations regarding the better photocatalytic efficiency of the ZnCr 900 photocatalyst in the MB degradation reaction.
Determining heavy metal leaching from the obtained photocatalysts is an important step in providing information on any potential secondary pollution during water treatment. For the most efficient photocatalysts (ZnCr 900), the amount of metal leaching into the MB and CBC solution during the photocatalytic degradation was measured using the following instruments: ICP-OES Thermo Scientific icap 6500 series (for Zn2+ leaching detection) and Perkin Elmer spectrophotometer (for Cr6+ leaching detection). The concentration of Zn in the MB solution was 1.39 mg·L−1, and in the BCB solution was 2.09 mg·L−1, which is lower than the WHO drinking water standards [69]. Furthermore, results showed that Cr6+ leaching was not detected (below the detection limit of the instrument), which was expected considering that only Cr3+ was used in the synthesis process and is known to be non-toxic and non-carcinogenic [93]. Therefore, the leaching study suggests that the ZnCr photocatalysts used do not initiate secondary pollution during water treatment.
3.4 Kinetic studies and predictive model of the photocatalytic reaction
The results of the kinetic study revealed that the experimental data obtained from photocatalytic reaction experiments for both investigated dyes were best fitted with linear regression and followed pseudo-first-order kinetics (Figure 5). The kinetic parameters obtained from the pseudo-first-order kinetic model are presented in Table 4, where the linear coefficients for determination, R 2, for all photocatalytic active samples ranged between 0.83 and 0.98, indicating a good correlation with the suggested model.
Kinetic parameters for MB and CBC photodegradation reaction
| Samples | MB kinetic parameters | BCB kinetic parameters | ||||
|---|---|---|---|---|---|---|
| k app (min−1) | R 2 | t 1/2 (min) | k app (min−1) | R 2 | t 1/2 (min) | |
| ZnCr 300 | 0.0022 | 0.97 | 315.1 | 0.0043 | 0.93 | 161.2 |
| ZnCr 500 | 0.0011 | 0.98 | 630.1 | 0.0046 | 0.96 | 150.7 |
| ZnCr 700 | 0.0031 | 0.97 | 223.6 | 0.009 | 0.83 | 77.0 |
| ZnCr 900 | 0.0134 | 0.89 | 51.7 | 0.0086 | 0.96 | 80.6 |
The kinetic study of azo dye photodegradation confirmed that the mechanism of both photocatalytic reactions followed the Langmuir–Hinshelwood kinetic model, which was expected since photocatalytic reactions on single substrates typically adhere to this kinetic model [55]. The most efficient photocatalyst ZnCr 900 exhibited the highest value of the apparent rate constant and the shortest reaction half-time.
To compare the photodegradation efficiency of ZnCr 900 for different water treatment systems/dyes, a scale-up parameter, the electrical energy per order (E EO), was calculated. This parameter represents the electrical energy required for the 90% pollutant degradation order-of-magnitude in a particular volume of contaminated water [69]. The lower value of E EO for the MB removal (8.6 kW·h·L−1·order−1), compared to BCB removal (13.4 kW·h·L−1·order−1), indicated a lower amount of energy/lower cost needed for the pollutant removal treatment.
The results of the ANN approach for photodegradation rate constant showed that the accuracy of networks could be improved by adding additional hidden neurons, as evidenced by the increasing trend of correlation coefficient values with the decrease of mean squared values [94]. ANNs exhibit significant advantages compared to traditional mathematical modelling methods and are widely used in chemical engineering for process optimization and various predictions [94,95]. The correlation coefficient R 2 and mean squared error (MSE) for 1 neuron were 0.814 and 0.0115 (Figure 4a and b), respectively, while the best results, without over-fitting, were achieved after adding ten neurons to the hidden layer, and the correlation coefficient and MSE were 0.979 and 0.0039, with tansig activation function.
ANN results: relationship between (a) MSE and (b) correlation coefficient (R 2) and the number of hidden layer neurons for the degradation rate constant and (c) relative importance of input variables: TTT, ODT, CS, and MPPD.
The ANN trained for the prediction of important valuables for the photodegradation rate constant (Figure 4c) showed the highest relative influence of TTT (35.1%), followed by the CS, ODT, and pore diameter of the most present pores (MPPD).
3.5 Effect of pollutant concentration and catalyst dosage on photocatalytic performance
The effect of MB dye concentration on photodegradation efficiency was analysed, and the results are presented in Figure 5a. ZnCr 900 was selected for this test since it exhibited the best removal efficiency in previous photocatalytic tests. It was observed that as the dye concentration increased, the efficiency improved, but this trend was not pronounced for higher concentration values. Consistent with previous reports [67,96,97], the removal efficiency increased with the initial dye concentration up to a specific limit, followed by a decrease in photodegradation efficiency. This decrease can be attributed to the light absorption of dye molecules, which inhibits the activation of photocatalytic active sites on the catalyst surface.
The influence of (a) concentration of MB dye solution (2.5, 5, 7.5, 10 and 15 mg·L−1) and (b) ZnCr 900 catalyst mass (25, 50, 75, 100 mg) on the photodegradation efficiency of MB removal.
The dosage of photocatalyst and its influence on the photocatalytic efficiency of MB removal was also studied (Figure 5b). The results indicate that the increase of photocatalyst mass did not improve photodegradation, probably due to the decrease in light penetration throughout the reaction mixture caused by light scattering on photocatalyst particles [2].
3.6 Stability tests
The stability of photocatalysts is an important factor that should be investigated in order to provide valuable insights into the catalysts’ properties. Therefore, the stability of ZnCr 900 for MB photodegradation under solar light irradiation was assessed after consecutive cycles of use without any additional treatment between cycles (Figure 6). The obtained results revealed a gradual decrease in photodegradation efficiency after every cycle. This behaviour could be attributed to the limited availability of active sites, hindering the mass transfer of reactive species. Since no treatment of the photocatalyst was conducted between cycles, such as washing and drying, further experimental studies are needed to elucidate the reasons for the deactivation of the photocatalyst and to enhance its photocatalytic performance. Nevertheless, the results indicated a moderate stability of the ZnCr 900 photocatalyst.
Stability tests of ZnCr 900 for MB photodegradation induced by solar light.
3.7 Antibacterial activity
Antibacterial tests were conducted to evaluate the antibacterial properties of all prepared samples by determining the total cell number of Gram-negative E. coli and Gram-positive S. aureus bacteria (as indicator strains) over time during contact with the ZnCr photocatalyst under solar irradiation (Figures 7 and 8).
![Figure 7
Reduction of E. coli cell number under antibacterial influence of the synthesized samples (a) in absence of light/in dark and (b) under solar light (experimental conditions: I [VIS] = 20.52 W·m−2; I [UVA] = 17.6 W·m−2).](/document/doi/10.1515/gps-2023-0269/asset/graphic/j_gps-2023-0269_fig_007.jpg)
Reduction of E. coli cell number under antibacterial influence of the synthesized samples (a) in absence of light/in dark and (b) under solar light (experimental conditions: I [VIS] = 20.52 W·m−2; I [UVA] = 17.6 W·m−2).
![Figure 8
Reduction of S. aureus cell number under antibacterial influence of the synthesized samples in (a) in the absence of light/in dark and (b) under solar light (experimental conditions: I [VIS] = 20.52 W m−2; I [UVA] = 17.6 W m−2).](/document/doi/10.1515/gps-2023-0269/asset/graphic/j_gps-2023-0269_fig_008.jpg)
Reduction of S. aureus cell number under antibacterial influence of the synthesized samples in (a) in the absence of light/in dark and (b) under solar light (experimental conditions: I [VIS] = 20.52 W m−2; I [UVA] = 17.6 W m−2).
It was observed that, in the dark, the variation of the number of cells for E. coli and S. aureus did not exceed ±1 log unit, leading to the conclusion that ZnCr photocatalysts did not exhibit antibacterial properties under the defined conditions of these experiments, regardless of the applied thermal treatment during sample preparation (Figures 7a and 8a).
The consistent number of microorganisms in the dark throughout the experiment duration suggests that the environmental factors were convenient for the selected microorganisms and did not adversely affect microbial growth. Moreover, the constant number of microbial cells in the control samples exposed to the solar light indicated that the light source did not influence the number reduction of both tested microorganisms (Figures 7b and 8b).
Under solar irradiation, a decrease in the cell number of E. coli was observed for all ZnCr photocatalysts with the exception of the ZnCr 100 samples (Figure 6b). The lack of antibacterial activity of the ZnCr 100 sample could be attributed to its phase composition, with only the LDH phase present, which could not induce the inhibition of cell growth. Thermally treated ZnCr samples gradually reduced the number of cells, with the ZnCr 900 sample exhibiting the highest antibacterial activity, inhibiting almost complete cell growth after only 3 h of contact. ZnCr 500 and ZnCr 700 achieved similar cell count reductions after 6 h of irradiation. The variation in antibacterial activity among samples could be explained by the amount of ZnO and ZnCr2O4 phases detected by XRD analysis, wherein an increase in TTT corresponded to higher intensity and sharpness of peaks, indicating a higher amount and higher crystallinity of the active phases.
A different antibacterial behaviour was observed when investigating the growth inhibition of S. aureus under solar light irradiation (Figure 8b). Samples thermally treated at temperatures higher than 500°C (ZnCr 500, 700, and 900) induced antibacterial activity under solar light irradiation, achieving practically complete growth inhibition after only 6 h of contact, whereas samples thermally treated at 100°C and 300°C did not reduce the initial number of cells during the experiment. As previously mentioned, the absence of antibacterial activity in samples is strongly connected with their phase composition and the amount of active phases.
Crystallinity and phase composition can significantly influence the photocatalytic properties of samples, including the ability to generate ROS under solar irradiation [22,98], which plays a crucial role in antibacterial activity [99]. The variations in thermal treatment most probably influenced ROS generation, impacting the antibacterial effectiveness against both bacteria. Therefore, higher amounts of active phases (ZnO and ZnCr2O4) resulted in more efficient antibacterial properties. Consequently, ZnCr 900 achieved the highest antibacterial activity for both bacteria due to the higher concentration of these active phases.
Based on the results and literature obtained, an antibacterial mechanism can be proposed for ZnCr photocatalysts, involving several key processes triggered by their photocatalytic activity under light irradiation. These processes lead to the generation of ROS and other effects that directly attack bacterial cells, resulting in their inactivation or death through oxidative damage to the cells. Additionally, the ROS can target the lipid bilayer of bacterial cell membranes, causing lipid peroxidation, compromising the membrane integrity, increasing permeability, and ultimately leading to cell lysis [100,101]. While the primary antibacterial action of ZnCr photocatalysts is attributed to ROS generation, the presence of zinc (Zn) and chromium (Cr) ions may also contribute to their antibacterial activity. Zn ions, in particular, are known for their antimicrobial properties, which can include disrupting membrane integrity and interfering with nutrient uptake and enzyme function within bacterial cells [102,103].
Furthermore, the investigation revealed differences in antibacterial activity between investigated E. coli and S. aureus, with the overall greater activity observed against E. coli. This disparity can be attributed to variations in bacterial cell wall structures and overall susceptibility to photocatalytic activity [104]. While Gram-negative bacteria (E. coli) have a more complex cell wall structure, they also have a more permeable outer membrane compared to Gram-positive bacteria (S. aureus), allowing better penetration of antibacterial agents, including ROS generated by the ZnCr photocatalysts, into the bacterial cell [57,104]. Also, E. coli possesses lipopolysaccharides (LPS) in the outer membrane that can be sensitive to oxidative stress [105,106]. Hence, it can be suggested that the solar light irradiation initiated ROS generation that targeted and disrupted LPS integrity, contributing to the more effective antibacterial activity against Gram-negative bacteria than Gram-positive bacteria [107]. The sensitivity of Gram-negative bacteria towards ROS generated by photocatalysts, such as singlet oxygen and superoxide radicals, can have a more pronounced effect on the cellular components [104,108] and agrees with our findings. Thereby, from the results obtained and from the literature, it could be suggested that the penetration of the generated ROS inside S. aureus required a longer time due to a thicker membrane [109]. Additionally, Gram-negative bacteria typically have a larger surface area-to-volume ratio due to their smaller size and complex shapes, providing more sites for interaction with the photocatalyst, and consequently, increasing the antibacterial activity [85]. In conclusion, despite the more complex cell wall structure of E. coli, the combination of factors and unique properties such as membrane permeability, sensitivity to ROS, and specific interactions with active phases of the photocatalyst can result in more efficient antibacterial activity against E. coli compared to S. aureus.
Different catalyst materials and the main variables that influence both photocatalytic and antibacterial activity are presented in Table 5. Each study had different experimental setups, making comparison of the results challenging. Hallak et al. [110] reported that TiO2, ZnO, and Au/ZnO showed a progressive increase in antibacterial activity against E. coli with gold-doped ZnO exhibiting the highest log reduction after 2 h under UVA light, indicating that Au doping enhances photocatalytic activity. ZnO samples presented high antibacterial efficiency against S. aureus and E. coli, likely due to the catalyst’s modification and the intense xenon lamp light source used for the experiment [107]. Also, BiVO4 demonstrated broad-spectrum antibacterial properties across various strains, including MRSA, under visible light, with effectiveness indicated by the diameter of the inhibition zones [111]. Additionally, TiO2 loading onto ZnAl LDH facilitated the formation of favourable interactions among active phases, improving the photocatalytic and antibacterial efficiency [22]. However, the results presented in our study demonstrate that the application of our suggested antibacterial experimental setup, along with enhanced photocatalyst-bacteria cell contact, achieved high photoinduced antibacterial efficiency even with significantly lower amounts of used photocatalysts, compared to other studies.
Comparison of photoinduced antibacterial efficiency of ZnCr 900 with the other published results
| Catalyst material | Catalyst dosage (mg·L−1) | Light source | Bacterial strains | Time (h) | Antibacterial efficiency | Ref. |
|---|---|---|---|---|---|---|
| TiO2 | 10,000 | 5 W·m−2 UVA | E. coli | 2 | 2.58 log CFU·mL−1 reduction | [110] |
| ZnO | 10,000 | 5 W·m−2 UVA | E. coli | 2 | 3.43 log CFU·mL−1 reduction | [110] |
| Au/ZnO | 10,000 | 5 W·m−2 UVA | E. coli | 2 | 3.98 log CFU·mL−1 reduction | [110] |
| ZnO | 1,000 | 4.52 W·cm−2 | S. aureus | 3 | 96.43% | [107] |
| Xenon lamp | E. coli | 95.72% | ||||
| BiVO4 | — | Visible light | S.aureus | 3 | IZa = 18 mm | [111] |
| MRSA | IZ = 15 mm | |||||
| E.aerogenes | IZ = 18 mm | |||||
| M. luteus | IZ = 19 mm | |||||
| K. pneumonia | IZ = 14 mm | |||||
| S. typhi | IZ = 20 mm | |||||
| S. paratyphi B | IZ = 12 mm | |||||
| P. vulgaris | IZ = 17 mm | |||||
| TiO2-ZnAl LDH | — | UV light | E. coli | 48 | IZ = 52 mm | [22] |
| S. aureus | ||||||
| ZnCr 900 | 500 | 20.52 W·m−2 OSRAM lamp | E. coli | 6 | ∼4.5 log CFU·mL−1 reduction | Present work |
| S. aureus |
aInhibition zones.
4 Conclusions
The study of the impact of thermal treatment on LDH-based ZnCr mixed metal oxides revealed enhanced photocatalytic efficiency in the removal of MB and BCB dyes. Furthermore, the antibacterial activity against E. coli and S. aureus demonstrated slight variations among photocatalysts, with ZnCr 900 exhibiting exceptional high performance under solar irradiation. The formation of active phases during the thermal treatment played a pivotal role in the observed high efficiency in both antibacterial and photodegradation processes. Structural and textural analysis unveiled the active phases, specific surface area, and pore size distribution of all samples. Structural analysis indicated the formation of the layered structure for the sample ZnCr 100 and the development of ZnO and ZnCr2O4 phases after thermal treatment, enhancing not only the photocatalytic efficiency but also antibacterial efficiency through synergistic and heterojunction effects. Moreover, kinetic studies using Langmuir–Hinshelwood kinetic modelling confirmed that the experimental data obtained from photocatalytic reaction experiments for both investigated dyes best fit the linear fit, following pseudo-first-order dynamics. Future studies regarding a detailed investigation of photocatalytic and antibacterial mechanisms should provide guidelines for the modification of LDH-based ZnCr photocatalysts that will further improve efficiency and stability. This study contributes valuable insights into the structure-dependent photocatalytic behaviour of ZnCr photocatalysts, paving the way for environmentally friendly applications of ZnCr photocatalysts in water purification and environmental remediation.
-
Funding information: This research was supported by the Science Fund of the Republic of Serbia, no. 7737365, ZERO-WASTE CONCEPT FOR FLOOD RESILIENT CITIES – Ø-Waste-Water and by the Ministry of Science, Technological Development and Innovation of the Republic of Serbia (Grant No. 451-03-47/2023-01/200134).
-
Author contributions: Djurdjica Karanovic: writing – original draft, methodology, investigation, formal analysis, data curation, and validation; Milica Hadnadjev-Kostic: writing – original draft, writing – review & editing, conceptualization, methodology, formal analysis, and validation; Tatjana Vulic: writing – review & editing, conceptualization, and validation; Sinisa Markov: formal analysis and data curation; Ana Tomic: formal analysis and data curation; Bojan Miljevic: formal analysis and data curation; Vladana Rajakovic-Ognjanovic: resources and validation. All authors have read and agreed to the published version of the manuscript.
-
Conflict of interest: Authors state no conflict of interest.
-
Data availability statement: All data generated or analysed during this study are included in this published article.
References
[1] Meng Z, Wu M, Yu Y, Meng F, Liu A, Komarneni S, et al. Selective removal of methyl orange and Cr anionic contaminants from mixed wastewater by in-situ formation of Zn-Al layered double hydroxides. Appl Clay Sci. 2018;161:1–5. 10.1016/j.clay.2018.04.008.Suche in Google Scholar
[2] Mohapatra L, Parida K. Zn-Cr layered double hydroxide: Visible light responsive photocatalyst for photocatalytic degradation of organic pollutants. Sep Purif Technol. 2012;91:73–80. 10.1016/j.seppur.2011.10.028.Suche in Google Scholar
[3] Hintsho N, Petrik L, Nechaev A, Titinchi S, Ndungu P. Photo-catalytic activity ofnanocompositesde carbon nanotube nanocomposites modified with silver and palladium nanoparticles. Appl Catal B-Environ. 2014;156-157:273–83. 10.1016/j.apcatb.2014.03.021.Suche in Google Scholar
[4] Pandey S, Do J, Kim J, Kang M. Fast and highly efficient removal of dye from aqueous solution using natural locust bean gum based hydrogels as adsorbent. Int J Biol Macromol. 2020;143:60–75. 10.1016/j.ijbiomac.2019.12.002.Suche in Google Scholar PubMed
[5] Srinivas C, Nagamani C, Gangadhar M, Raja Sekhar M. Spectrophotometric studies on removal of brilliant cresyl blue from aqueous solution by using lead sulphide. Asian J Chem. 2010;22(7):5045–8. https://asianpubs.org/index.php/ajchem/article/view/11711.Suche in Google Scholar
[6] Zhang O, Wang D, Yu R, Luo L, Li W, Cheng J, et al. Excellent photocatalytic degradation of rhodamine B over Bi2O3 supported on Zn-MOF nanocomposites under visible light. Green Process Synth. 2023;12(1):20228123. 10.1515/gps-2022-8123.Suche in Google Scholar
[7] Al-Tohamy R, Ali SS, Li F, Okasha KM, Mahmoud YAG, Elsamahy T, et al. A critical review on the treatment of dye-containing wastewater: Ecotoxicological and health concerns of textile dyes and Ref. 21: Please provide the publisher location.possible remediation approaches for environmental safety. Ecotox Environ Safe. 2022;231:113160. 10.1016/j.ecoenv.2021.113160.Suche in Google Scholar PubMed
[8] Thangaraj S, Bankole PO, Sadasivam SK. Microbial degradation of azo dyes by textile effluent adapted, Enterobacter hormaechei under microaerophilic condition. Microbiol Res. 2021;250:126805. 10.1016/j.micres.2021.126805.Suche in Google Scholar PubMed
[9] Pare B, Raghuvanshi D, Dixit R, Swami D. Decolorization and mineralization of hazardous brilliant cresyl blue dye using visible light and TiO2 as photocatalyst. Int J Chem Sci. 2013;11(4):1876–90.Suche in Google Scholar
[10] Tounsadi H, Metarfi Y, Taleb M, El Rhazi K, Rais Z. Impact of chemical substances used in textile industry on the employee’s health: epidemiological study. Ecotox Environ Safe. 2020;197:110594. 10.1016/j.ecoenv.2020.110594.Suche in Google Scholar PubMed
[11] Morais DL, Primo FL, Gobo GG, da Costa CRV, Tedesco AC, de Oliveira DP. Genotoxicity Assessment of reactive and disperse textile dyes using human dermal equivalent (3D cell culture system). J Toxicol Environ Heal A. 2015;78(7):466–80. 10.1080/15287394.2014.999296.Suche in Google Scholar PubMed
[12] Motene K, Mahlaule-Glory LM, Ngoepe NM, Mathipa MM, Hintsho-Mbita NC. Photocatalytic degradation of dyes and removal of bacteria using biosynthesised flowerlike NiO nanoparticles. Int J Environ Anal Chem. 2023;103(5):1107–22. 10.1080/03067319.2020.1869730.Suche in Google Scholar
[13] Regmi C, Joshi B, Ray SK, Gyawali G, Pandey RP. Understanding mechanism of photocatalytic microbial decontamination of environmental wastewater. Front Chem. 2018;6:33. 10.3389/fchem.2018.00033.Suche in Google Scholar PubMed PubMed Central
[14] O’Dowd K, Nair KM, Pillai SC. Photocatalytic degradation of antibiotic-resistant genes and bacteria using 2D nanomaterials: What is known and what are the challenges? Curr Opin Green Sustainable. 2021;30:100471. 10.1016/j.cogsc.2021.100471.Suche in Google Scholar
[15] Hadnadjev-Kostic M, Vulic T, Karanovic D, Milanovic M. Advanced dye removal by multifunctional layered double hydroxide based materials: Adsorption and kinetic studies. J Serb Chem Soc. 2022;87:1011–24. 10.2298/JSC220228034H.Suche in Google Scholar
[16] Sarkar M. Light-responsive biodegradation of wastewater pollutants: New developments and potential perspectives. J Hazard Mater Adv. 2023;10:100281. 10.1016/j.hazadv.2023.100281.Suche in Google Scholar
[17] Hadnadjev-Kostic M, Karanovic Dj, Vulic T, Dostanić J, Lončarević D. Photocatalytic properties of ZnFe-mixed oxides synthesized via a simple route for water remediation. Green Process Synth. 2023;12:20228153. 10.1515/gps-2022-8153.Suche in Google Scholar
[18] Abderrazek K, Najoua F, Srasra E. Synthesis and characterization of [Zn-Al] LDH: Study of the effect of calcination on the photocatalytic activity. Appl Clay Sci. 2016;119:229–35. 10.1016/j.clay.2015.10.014.Suche in Google Scholar
[19] Ahmad I, Khan SB, Kamal T, Asiri AM. Visible light activated degradation of organic pollutants using zinc–iron selenide. J Mol Liq. 2017;229:429–35. 10.1016/j.molliq.2016.12.061.Suche in Google Scholar
[20] Belver C, Bedia J, Gomez-Aviles A, Penas-Garzon M, Rodriguez JJ. Semiconductor photocatalysis for water purification. In: Thomas S, Pasquini D, Leu SZ, Gopakumar DA, editors. Nanoscale Materials in Water Purification. The Netherlands: Elsevier; 2019. p. 581–651.10.1016/B978-0-12-813926-4.00028-8Suche in Google Scholar
[21] Hadnadjev-Kostic M, Vulic T, Dostanic J, Loncarevic D. Design and application of various visible light responsive metal oxide photocatalysts. In: Hussain CM, Mishra AK, editors. Handbook of Smart Photocatalytic Materials: Fundamentals, Fabrications & Water Resources Applications. The Netherlands: Elsevier; 2020. p. 65–99.10.1016/B978-0-12-819051-7.00003-8Suche in Google Scholar
[22] Hadnadjev-Kostic M, Vulic T, Marinkovic-Neducin R, Lončarević D, Dostanić J, Markov S, et al. Photoinduced properties of photocatalysts: A study on the modified structural, optical and textural properties of TiO2–ZnAl layered double hydroxide based materials. J Clean Prod. 2017;164:1–18. 10.1016/j.jclepro.2017.06.091.Suche in Google Scholar
[23] Han C, Yang MQ, Weng B, Xu Y. Improving the photocatalytic activity and anti-photocorrosion of semiconductor ZnO by coupling with versatile carbon. Phys Chem Chem Phys. 2014;16:16891. 10.1039/c4cp02189d.Suche in Google Scholar PubMed
[24] Jaffri S, Ahmad K. Foliar-mediated Ag:ZnO nanophotocatalysts: green synthesis, characterization, pollutants degradation, and in vitro biocidal activity. Green Process Synth. 2019;8(1):172–82. 10.1515/gps-2018-0058.Suche in Google Scholar
[25] Ong CB, Ng LY, Mohammad AW. A review of ZnO nanoparticles as solar photocatalysts: Synthesis, mechanisms and applications. Renew Sustainable Energ Rev. 2018;81:536–51. 10.1016/j.rser.2017.08.020.Suche in Google Scholar
[26] Azam A, Ahmed AS, Oves M, Khan M, Memic A. Size-dependent antimicrobial properties of CuO nanoparticles against Gram-positive and -negative bacterial strains. Int J Nanomedicine. 2012;7:3527–35. 10.2147/IJN.S29020.Suche in Google Scholar PubMed PubMed Central
[27] Kamari HM, Al-Hada NM, Baqer AA, Shaari AH, Saion E. Comprehensive study on morphological, structural and optical properties of Cr2O3 nanoparticle and its antibacterial activities. J Mater Sci: Mater Electron. 2019;30:8035–46. 10.1007/s10854-019-01125-2.Suche in Google Scholar
[28] Arrabito G, Bonasera A, Prestopino G, Orsini A, Mattoccia A, Martinelli E, et al. Layered double hydroxides: a toolbox for chemistry and biology. Crystals. 2019;9(7):361. 10.3390/cryst9070361.Suche in Google Scholar
[29] Janani B, Syed A, Sruthi L, Sivaranjani PR, Elgorban AM, Bahkali AH, et al. Visible light driven photocatalytic activity and efficient antibacterial activity of ZnFe2O4 decorated CdO nanohybrid heterostructures synthesized by ultrasonic-assisted method. Colloid Surface A. 2021;628:12730. 10.1016/j.colsurfa.2021.127307.Suche in Google Scholar
[30] Li M, Li L, Lin S. Efficient antimicrobial properties of layered double hydroxide assembled with transition metals via a facile preparation method. Chinese Chem Lett. 2020;31(6):1511–15. 10.1016/j.cclet.2019.09.047.Suche in Google Scholar
[31] Mishra G, Dash B, Pandey S, Mohanty PP. Antibacterial actions of silver nanoparticles incorporated Zn–Al layered double hydroxide and its spinel. J Environ Chem. 2013;1(4):1124–30. 10.1016/j.jece.2013.08.031.Suche in Google Scholar
[32] Kumar A, Singla Y, Sharma M, Bhardwaj A, Krishnan V. Two dimensional S-scheme Bi2WO6–TiO2–Ti3C2 nanocomposites for efficient degradation of organic pollutants under natural sunlight. Chemosphere. 2022;308:136212. 10.1016/j.chemosphere.2022.136212.Suche in Google Scholar PubMed
[33] Sharma V, Kumar A, Kumar A, Kirshnan V. Enhanced photocatalytic activity of two dimensional ternary nanocomposites of ZnO–Bi2WO6–Ti3C2 MXene under natural sunlight irradiation. Chemosphere. 2022;287:132119. 10.1016/j.chemosphere.2021.132119.Suche in Google Scholar PubMed
[34] Mohanty S, Sharma M, Kumar A, Krishnan V. Hot electron-mediated photocatalytic degradation of ciprofloxacin using Au-decorated SrTiO3- and Ti3C2 MXene-based interfacial heterostructure nanoarchitectonics. J Phys Chem C. 2023;127(36):17711–22. 10.1021/acs.jpcc.3c03573.Suche in Google Scholar
[35] Choudhary S, Sharma M, Krishnan V, Mohapatra S. Facile synthesis, structural, morphological, photocatalytic and optical properties of CoFe2O4/ZnO hybrid nanostructures. Ceram Int. 2022;48(22):34043–45. 10.1016/j.ceramint.2022.08.003.Suche in Google Scholar
[36] Choudhary S, Sharma M, Krishnan V, Mohapatra S. Facile synthesis of Ce doped ZnO nanowires for efficient photocatalytic removal of organic pollutants from water. Mater Today Commun. 2023;34:105361. 10.1016/j.mtcomm.2023.105361. Suche in Google Scholar
[37] da Silva ES, Prevot V, Forano C, Wong-Wah-Chung P, Burrows HD, Sarakha M. Heterogeneous photocatalytic degradation of pesticides using decatungstate intercalated odelling s layered double hydroxides. Environ Sci Pollut R. 2014;21:11218. 10.1007/s11356-014-2971-z.Suche in Google Scholar PubMed
[38] Yang Z, Li X, Huang Y, Chen Y, Wang A, Wang Y, et al. Facile synthesis of cobalt-iron layered double hydroxides nanosheets for direct activation of peroxymonosulfate (PMS) during degradation of fluoroquinolones antibiotics. J Clean Prod. 2021;310:127584. 10.1016/j.jclepro.2021.127584.Suche in Google Scholar
[39] Balcik C, Ozbey-Unal B, Sahin B, Aydin EB, Cifcioglu-Gozuacik B, Keyikoglu R, et al. Development of ZnFeCe layered double hydroxide incorporated thin film nanocomposite membrane with enhanced separation performance and antibacterial properties. Water. 2023;15(2):264. 10.3390/w15020264. Suche in Google Scholar
[40] Cardinale AM, Alberti S, Pietri Reverberi A, Catauro M, Ghibaudo N, Fortunato M. Antibacterial and photocatalytic activities of LDH-based sorbents of different compositions. Microorganisms. 2023;11(4):1045. 10.3390/microorganisms11041045. Suche in Google Scholar
[41] Vaccari A. Clays and catalysis: a promising future. Appl Clay Sci. 1999;14(4):161–98. 10.1016/S0169-1317(98)00058-1.Suche in Google Scholar
[42] Cavani F, Trifiro F, Vaccari A. Hydrotalcite-type anionic clays: Preparation, properties and applications. Catal Today. 1991;11:173–301. 10.1016/0920-5861(91)80068-K.Suche in Google Scholar
[43] Braterman PS, Xu ZP, Yarberry F. Layered double hydroxides (LDHs). In: Auerbach SM, Carrado KA, Dutta PK, editors. Handbook of layered materials. New York: Marcel Dekker Inc; 2004. p. 420–49.10.1002/chin.200516229Suche in Google Scholar
[44] Fang L, Xue D. Applications of layered double hydroxides. In: Duan X, Evans DG, editors. Layered Double Hydroxides. Structure and Bonding. Berlin: Springer; 2009. p. 193–223.Suche in Google Scholar
[45] Vaccari A. Preparation and catalytic properties of cationic and anionic clays. Catal Today. 1998;41(1–3):53–71. 10.1016/S0920-5861(98)00038-8.Suche in Google Scholar
[46] Serwicka EM, Bahranowski K. Environmental catalysis by tailored materials derived from layered minerals. Catal Today. 2004;90:85–92. 10.1016/j.cattod.2004.04.012.Suche in Google Scholar
[47] Xu ZP, Zhang J, Adebajo MO, Zhang H, Zhou C. Catalytic applications of layered double hydroxides and derivatives. Appl Clay Sci. 2011;53:139–50. 10.1016/j.clay.2011.02.007.Suche in Google Scholar
[48] Vulic T, Reitzmann A, Lázár K. Thermally activated iron containing layered double hydroxides as potential catalyst for N2O abatement. Chem Eng J. 2012;207-208:913–22. 10.1016/j.cej.2012.06.152.Suche in Google Scholar
[49] Vulic T, Hadnadjev M, Marinkovic-Neducin R. Structure and morphology of Mg–Al–Fe-mixed oxides derived from layered double hydroxides. J Microsc Oxford. 2008;232(3):634–38. 10.1111/j.1365-2818.2008.02130.x.Suche in Google Scholar PubMed
[50] Bencherif S, Gallardo J, Carillo-Berdugo I, Bahmani A. Navas J. Synthesis, characterization and photocatalytic performance of calcined ZnCr‐layered double hydroxides. Nanomaterials. 2021;11(11):3051. 10.3390/nano11113051.Suche in Google Scholar PubMed PubMed Central
[51] Ahmed M, Khan M, Khan S, Akhtar K, Bakhsh E, Khan S, et al. Ni–Al-layered double-hydroxide photocatalyst for the visible light-assisted photodegradation of organic dye pollutants. Appl Nanosci. 2022;12(11):3597–606. 10.1007/s13204-022-02350.Suche in Google Scholar
[52] Takei T, Miura A, Kumada N. Soft-chemical synthesis and catalytic activity of Ni-Al and Co-Al layered double hydroxides (LDHs) intercalated with anions with different charge density. Journal Asian Ceram Soc. 2014;2(3):289–96. 10.1016/j.jascer.2014.06.002.Suche in Google Scholar
[53] Gajendiran J, Rajendran V. Synthesis and characterization of coupled semiconductor metal oxide (ZnO/CuO) nanocomposite. Mater Lett. 2014;116:311–13. 10.1016/j.matlet.2013.11.063.Suche in Google Scholar
[54] Torbati S, Motlagh PY, Khataee A. Toxicity of ZnFe-SO4 layered double hydroxide in Tetradesmus obliquus and evaluation of some physiological responses of the microalgae for stress management. Sci Rep. 2024;14:975. 10.1038/s41598-023-51042-y.Suche in Google Scholar PubMed PubMed Central
[55] El Mersly L, El Mouchtari M, El Moujahid M, Forano C, El Haddad M, Briche S, et al. ZnCr-LDHs with dual adsorption and photocatalysis capability for the removal of acid orange 7 dye in aqueous solution. J Sci-Adv Mater Dev. 2021;6(1):118–26. 10.1016/j.jsamd.2020.08.002.Suche in Google Scholar
[56] Paušová Š, Krýsa J, Jirkovský J, Forano C, Mailhot G, Prevot V. Insight into the photocatalytic activity of ZnCr–CO3 LDH and derived mixed oxides. Appl Catal B-Environ. 2015;170–171:25–33. 10.1016/j.apcatb.2015.01.029.Suche in Google Scholar
[57] Sadeghi Rad T, Khataee A, Arefi-Oskoui S, Sadeghi Rad S, Orooji Y, Gengec E, et al. Graphene-based ZnCr layered double hydroxide nanocomposites as bactericidal agents with high sonophotocatalytic performances for degradation of rifampicin. Chemosphere. 2022;286:131740. 10.1016/j.chemosphere.2021.131740.Suche in Google Scholar PubMed
[58] Keerthiraj N, Byrappa K, Deepthi B. Photocatalytic decolorization of brilliant blue dye using Zinc oxide in the presence of sunlight. IJRR. 2016;3(11):43–50. 10.13140/RG.2.2.30765.38888.Suche in Google Scholar
[59] Al-Gubury HY. Al – Murshidy SG. Photocatalytic decolorization of brilliant cresyl blue using zinc oxide. Int J PharmTech Res. 2015;8(2):289–97.Suche in Google Scholar
[60] Vulic T, Hadnadjev-Kostic M, Rudic O, Radeka M, Marinkovic-Neducin R, Ranogajec J. Improvement of cement-based mortars by application of photocatalytic active Ti–Zn–Al nanocomposites. Cement Concrete Comp. 2013;36:121–27. 10.1016/j.cemconcomp.2012.07.005.Suche in Google Scholar
[61] Vulic T, Reitzmann A, Ranogajec J, Marinkovic-Neducin R. The influence of synthesis method and Mg-Al-Fe content on the thermal stability of layered double hydroxides. J Therm Anal Calorim. 2012;110(1):227–33. 10.1007/s10973-012-2230-9.Suche in Google Scholar
[62] Hadnadjev-Kostic M, Vulic T, Marinkovic-Neducin R. Thermal activation of layered hydroxide-based catalysts. In: Tiwari A, Raj B, editors. Reactions and Mechanisms in Thermal Analysis of Advanced Materials. Wiley-Scrivener; 2015. p. 483–514.10.1002/9781119117711.ch20Suche in Google Scholar
[63] Hadnadjev-Kostic M, Vulic T, Ranogajec J, Marinkovic-Neducin R, Radosavljevic-Mihajlovic A. Thermal and photocatalytic behaviour of Ti/LDH nanocomposites. J Therm Anal Calorim. 2013;111(2):1155–62. 10.1007/s10973-012-2226-5.Suche in Google Scholar
[64] Karanovic D, Hadnadjev-Kostic M, Vulic T, Milanovic M, Rajakovic-Ognjanovic V, Marinkovic-Neducin R. The influence of the coprecipitation synthesis methods on photodegradation efficiency of ZnFe based photocatalysts. J Serb Chem Soc. 2024:1–12. 10.2298/JSC231106005K.Suche in Google Scholar
[65] Ahmed AAA, Talib ZA, bin Hussein MZ. Thermal, optical and dielectric properties of Zn–Al layered double hydroxide. Appl Clay Sci. 2012;56:68–76. 10.1016/j.clay.2011.11.024.Suche in Google Scholar
[66] Ahmed AAA, Talib ZA, bin Hussein MZ, Zakaria A. Improvement of the crystallinity and photocatalytic property of zinc oxide as calcination product of Zn–Al layered double hydroxide. J Alloy Compd. 2012;539:154–60. 10.1016/j.jallcom.2012.05.093.Suche in Google Scholar
[67] Raheb I, Manlla MS. Kinetic and thermodynamic studies of the degradation of Methylene blue by photo-Fenton reaction. Heliyon. 2021;7(6):e07427. 10.1016/j.heliyon.2021.e07427.Suche in Google Scholar PubMed PubMed Central
[68] Hassandoost R, Kotb A, Movafagh Z, Esmat M, Guegan R, Endo S, et al. Nanoarchitecturing bimetallic manganese cobaltite spinels for sonocatalytic degradation of oxytetracycline. Chem Eng J. 2022;431:133581. 10.1016/j.cej.2021.133851.Suche in Google Scholar
[69] Keyikoğlu R, Doğan IN, Khataee A, Orooji Y, Kobya M, Yoon Y. Synthesis of visible light responsive ZnCoFe layered double hydroxide towards enhanced photocatalytic activity in water treatment. Chemosphere. 2022;309:136534. 10.1016/j.chemosphere.2022.136534.Suche in Google Scholar PubMed
[70] Bolton J, Bircher K, Tumas W, Tolman C. Figures-of-merit for the technical development and application of advanced oxidation technologies for both electric- and solar-driven systems (IUPAC Technical Report. Pure Appl Chem. 2001;73(4):627–37. 10.1351/pac200173040627.Suche in Google Scholar
[71] Carbone M, Briancesco R, Bonadonna L. Antimicrobial power of Cu/Zn mixed oxide nanoparticles to Escherichia coli. Environ Nanotechnol Monit Manag. 2017;7:97–102. 10.1016/j.enmm.2017.01.005.Suche in Google Scholar
[72] Kokulnathan T, Wang T, Ahmed F, Alshahrani T. Hydrothermal synthesis of ZnCr-LDH/Tungsten carbide composite: A disposable electrochemical strip for mesalazine analysis. Chem Eng J. 2023;451:138884. 10.1016/j.cej.2022.138884.Suche in Google Scholar
[73] Sohail M, Kim H, Kim T. Enhanced photocatalytic performance of a Ti-based metal-organic framework for hydrogen production: Hybridization with ZnCr-LDH nanosheets. Sci Rep. 2019;9:7584. 10.1038/s41598-019-44008-6.Suche in Google Scholar PubMed PubMed Central
[74] Dutta K, Das S, Pramanik A. Concomitant synthesis of highly crystalline Zn–Al layered double hydroxide and ZnO: Phase interconversion and enhanced photocatalytic activity. J Colloid Interf Sci. 2012;366(1):28–36. 10.1016/j.jcis.2011.09.081.Suche in Google Scholar PubMed
[75] Morimoto K, Tamura K, Iyi N, Ye J, Yamada H. Adsorption and photodegradation properties of anionic dyes by layered double hydroxides. J Phys Chem Solids. 2011;72(9):1037–45. 10.1016/j.jpcs.2011.05.018.Suche in Google Scholar
[76] Zhu Y, Wu P, Yang S, Lu Y, Li W, Zhu N. Synergetic effect of functionalized carbon nanotubes on ZnCr–mixed metal oxides for enhanced solar light-driven photocatalytic performance. RSC Adv. 2016;6:37689–700.10.1039/C6RA05291FSuche in Google Scholar
[77] Saravanan R, Thirumal E, Gupta VK, Narayanan V, Stephen K. The photocatalytic activity of ZnO prepared by simple thermal decomposition method at various temperatures. J Mol Liq. 2013;177:394–401. 10.1016/j.molliq.2012.10.018.Suche in Google Scholar
[78] Hadnadjev Kostic M, Vulic T, Zoric D, Marinkovic-Neducin R. The influence of the UV irradiation intensity on photocatalytic activity of ZnAl layered double hydroxides and derived mixed oxides. Chem Ind Chem Eng Q. 2012;18:295–303. 10.2298/CICEQ110923006H.Suche in Google Scholar
[79] Wang Z, Jiang X, Pan M, Shi Y. Nano-scale pore structure and its multi-fractal characteristics of tight sandstone by N2 adsorption/desorption analyses: a case study of shihezi formation from the sulige gas filed, Ordos Basin, China. Minerals. 2020;10(4):377. 10.3390/min10040377.Suche in Google Scholar
[80] Lee SB, Ko EH, Park JY, Oh JM. Mixed metal oxide by calcination of layered double hydroxide: parameteres affecting surface area. Nanomaterials. 2021;11(5):1153. 10.3390/nano11051153.Suche in Google Scholar PubMed PubMed Central
[81] Galarneau A, Villemot F, Rodriguez J, Fajula F, Coasne B. Validity of the t-plot Method to Assess Microporosity in Hierarchical Micro/Mesoporous Materials. Langmuir. 2014;30:13266. 10.1021/la5026679.Suche in Google Scholar PubMed
[82] Singh P, Abdullah M, Sagadevan S, Kaur C, Ikram S. Highly sensitive ethanol sensor based on TiO2 nanoparticles and its photocatalyst activity. Optik. 2019;182:512–8. 10.1016/j.ijleo.2019.01.077.Suche in Google Scholar
[83] Waghchaure RH, Adole VA, Jagdale BS. Photocatalytic degradation of methylene blue, rhodamine B, methyl orange and Eriochrome black T dyes by modified ZnO nanocatalysts: A concise review. Inorg Chem Commun. 2022;143:109764. 10.1016/j.inoche.2022.109764.Suche in Google Scholar
[84] Yang C, Dong W, Cui G, Zhao Y, Shi X, Xia X, et al. Highly-efficient photocatalytic degradation of methylene blue by PoPD-modified TiO 2 nanocomposites due to photosensitization-synergetic effect of TiO2 with PoPD. Sci Rep. 2017;7:3973. 10.1038/s41598-017-04398-x.Suche in Google Scholar PubMed PubMed Central
[85] Singh K, Bhattu M, Singh G, Mubarak NM, Singh J. Light-absorption-driven photocatalysis and antimicrobial potential of PVP-capped zinc oxide nanoparticles. Sci Rep. 2023;13:13886. 10.1038/s41598-023-41103-7.Suche in Google Scholar PubMed PubMed Central
[86] Sabry RS, Rahmah MI, Aziz WJ. A systematic study to evaluate effects of stearic acid on superhydrophobicity and photocatalytic properties of Ag-doped ZnO nanostructures. J Mater Sci: Mater Electron. 2020;31:13382–91. 10.1007/s10854-020-03893-8.Suche in Google Scholar
[87] Abd-Allah AAA, Ahmed Y, El-sheikh S, Youssef A, Amin A. Synthesis of Zinc aluminate nanoparticles from aluminum/zinc sludge for degradation of brilliant cresyl blue under visible light irradiation. J Water Environ Nanotech. 2022;7(3):288–305. 10.22090/jwent.2022.03.005.Suche in Google Scholar
[88] Mathai J, Anjana MP, Aleena PA, Thomas SA, Jose AK, Kunjumon J, et al. Cr doped ZnO nanoparticles as photocatalyst for the degradation of methylene blue dye. J Indian Chem Soc. 2023;100(9):101067. 10.1016/j.jics.2023.101067.Suche in Google Scholar
[89] Rashid M, Ikram M, Hiader A, Naz S, Haider J, Ul-Hamid A, et al. Photocatalytic, dye degradation, and bactericidal behavior of Cu-doped ZnO nanorods and their molecular docking analysis. Dalton Trans. 2020;49:8314–30. 10.1039/D0DT01397H.Suche in Google Scholar
[90] Yarahmadi M, Maleki-Ghaleh H, Mehr ME, Dargahi Z, Rasouli F, Siadati MH. Synthesis and characterization of Sr-doped ZnO nanoparticles for photocatalytic applications. 2021;853:157000. 10.1016/j.jallcom.2020.157000.Suche in Google Scholar
[91] Fouda SR, Yahia IS, Hussein MSA. Photocatalytic degradation of methylene blue and rhodamine B using one-pot synthesized nickel oxide grafted glycine (NiO @GLY) nanostructured: Oxygen vacancies effect. J Photoch Photobio A. 2023;439:114622. 10.1016/j.jphotochem.2023.114622.Suche in Google Scholar
[92] Wang Z, Wang J, Pan Y, Liu F, Lai Y, Li J, et al. Preparation and characterization of a novel and recyclable InVO4/ZnFe2O4 composite for methylene blue removal by adsorption and visible-light photocatalytic degradation. Appl Surf Sci. 2020;501:144006. 10.1016/j.apsusc.2019.144006.Suche in Google Scholar
[93] Zhitkovich A. Chromium in Drinking Water: Sources, Metabolism, and Cancer Risks. Chem Res Toxicol. 2011;24(10):1617–29. 10.1021/tx200251t.Suche in Google Scholar PubMed PubMed Central
[94] Hadnadjev-Kostic M, Vulić T, Lukić N, Jokić A, Karanovic D. Photocatalytic performance of TiO2-ZnAl LDH based materials: kinetics and neural networks approach. Pol J Environ Stud. 2022;31(5):4117–25. 10.15244/pjoes/147023.Suche in Google Scholar
[95] Bharadwaj A, Singh M, Niju S, Anantharaman KN. Biodiesel production from rubber seed oil using calcium oxide derived from eggshell as catalyst – optimization and odelling studies. Green Process Synth. 2019;8(1):430–42. 10.1515/gps-2019-0011.Suche in Google Scholar
[96] Khan I, Saeed K, Zekker I, Zhang B, Hendi AH, Ahmad A, et al. Review on methylene blue: its properties, uses, toxicity and photodegradation. Water. 2022;14(2):242. 10.3390/w14020242.Suche in Google Scholar
[97] Blažeka D, Car J, Klobučar N, Jurov A, Zavašnik J, Jagodar A, Kovačević E, Krstulović N. Photodegradation of methylene blue and rhodamine B using laser-synthesized ZnO nanoparticles. Materials. 2020;13(19):4357. 10.3390/ma13194357.Suche in Google Scholar PubMed PubMed Central
[98] Chuaicham C, Inoue T, Balakumar V, Tian Q, Sasaki K. Fabrication of visible-light-active ZnCr mixed metal oxide/fly ash for photocatalytic activity toward pharmaceutical waste ciprofloxacin. J Ind Eng Chem. 2022;108:263–73. 10.1016/j.jiec.2022.01.006.Suche in Google Scholar
[99] Janani FZ, Taoufik N, Khiar H, Boumya W, Elhalil A, Sadiq M, et al. Nanostructured layered double hydroxides based photocatalysts: Insight on synthesis methods, application in water decontamination/splitting and antibacterial activity. Surf Interfaces. 2021;25:101263. 10.1016/j.surfin.2021.101263.Suche in Google Scholar
[100] Dadakhani S, Dehghan G, Khataee A, Erfanparast A. Design and application of histidine-functionalized ZnCr-LDH nanozyme for promoting bacteria-infected wound healing. RSC Adv. 2024;14:1195–206. 10.1039/D3RA07364E.Suche in Google Scholar
[101] Markov S, Vidakovic A. Testing methods for antimicrobial activity of TiO2 photocatalyst. Acta Period Technol. 2014;45:141–52. 10.2298/APT1445141M.Suche in Google Scholar
[102] Pasquet J, Chevalier Y, Pelletier J, Couval E, Bouvier D, Bolzinger MA. The contribution of zinc ions to the antimicrobial activity of zinc oxide. Colloid Surf A. 2014;457:263–74. 10.1016/j.colsurfa.2014.05.057.Suche in Google Scholar
[103] Almoudi MM, Hussein AS, Abu Hassan MI, Zain NM. A systematic review on antibacterial activity of zinc against Streptococcus mutans. Saudi Dent J. 2018;30(4):283–91. 10.1016/j.sdentj.2018.06.003.Suche in Google Scholar PubMed PubMed Central
[104] Raghupathi K, Koodali RT, Manna AC. Size-dependent bacterial growth inhibition and mechanism of antibacterial activity of zinc oxide nanoparticles. Langmuir. 2011;27(7):4020–8. 10.1021/la104825u.Suche in Google Scholar PubMed
[105] Sharma R, Arizaga, Saini AK, Shandilya P. Layered double hydroxide as multifunctional materials for environmental remediation: from chemical pollutants to microorganisms. Sustain Mater Technol. 2021;29:e00319. 10.1016/j.susmat.2021.e00319.Suche in Google Scholar
[106] Li J, Xie B, Xia K, Li Y, Han J, Zhao C. Enhanced antibacterial activity of silver doped titanium dioxide-chitosan composites under visible light. Materials. 2018;11(8):1403. 10.3390/ma11081403.Suche in Google Scholar PubMed PubMed Central
[107] Kim S, Park H, Pandey S, Jeong D, Lee C-T, Do JY, et al. Effective antibacterial/photocatalytic activity of zno nanomaterials synthesized under low temperature and alkaline conditions. Nanomaterials. 2022;12(24):4417. 10.3390/nano12244417.Suche in Google Scholar PubMed PubMed Central
[108] Rutherford D, Jíra J, Kolářová K, Matolínová I, Mičová J, Remeš Z, et al. Growth inhibition of gram-positive and gram-negative bacteria by zinc oxide hedgehog particles. Int J Nanomed. 2021;16:3541–54. 10.2147/IJN.S300428.Suche in Google Scholar PubMed PubMed Central
[109] Pan F, Altenried S, Zuber F, Wagner RS, Su YH, Rottmar M, et al. Photo-activated titanium surface confers time dependent bactericidal activity towards Gram positive and negative bacteria. Colloid Surf B. 2021;206:111940.10.1016/j.colsurfb.2021.111940Suche in Google Scholar PubMed
[110] Hallak MA, Verdier T, Bertron A, Castello Lux K, El Atti O, Fajerwerg K, et al. Comparison of photocatalytic biocidal activity of TiO2, ZnO and Au/ZnO on escherichia coli and on aspergillus niger under light intensity close to real-life conditions. Catalysts. 2023;13(7):1139. 10.3390/catal13071139.Suche in Google Scholar
[111] Pramila S, Nagaraju G, Mallikarjunaswamy C, Latha KC, Chandan S, Ramu R, et al. Green synthesis of BiVO4 nanoparticles by microwave method using aegle marmelos juice as a fuel: photocatalytic and antimicrobial study. Anal Chem Lett. 2020;10(3):298–306. 10.1080/22297928.2020.1785935.Suche in Google Scholar
© 2024 the author(s), published by De Gruyter
This work is licensed under the Creative Commons Attribution 4.0 International License.
Artikel in diesem Heft
- Research Articles
- Green polymer electrolyte and activated charcoal-based supercapacitor for energy harvesting application: Electrochemical characteristics
- Research on the adsorption of Co2+ ions using halloysite clay and the ability to recover them by electrodeposition method
- Simultaneous estimation of ibuprofen, caffeine, and paracetamol in commercial products using a green reverse-phase HPTLC method
- Isolation, screening and optimization of alkaliphilic cellulolytic fungi for production of cellulase
- Functionalized gold nanoparticles coated with bacterial alginate and their antibacterial and anticancer activities
- Comparative analysis of bio-based amino acid surfactants obtained via Diels–Alder reaction of cyclic anhydrides
- Biosynthesis of silver nanoparticles on yellow phosphorus slag and its application in organic coatings
- Exploring antioxidant potential and phenolic compound extraction from Vitis vinifera L. using ultrasound-assisted extraction
- Manganese and copper-coated nickel oxide nanoparticles synthesized from Carica papaya leaf extract induce antimicrobial activity and breast cancer cell death by triggering mitochondrial caspases and p53
- Insight into heating method and Mozafari method as green processing techniques for the synthesis of micro- and nano-drug carriers
- Silicotungstic acid supported on Bi-based MOF-derived metal oxide for photodegradation of organic dyes
- Synthesis and characterization of capsaicin nanoparticles: An attempt to enhance its bioavailability and pharmacological actions
- Synthesis of Lawsonia inermis-encased silver–copper bimetallic nanoparticles with antioxidant, antibacterial, and cytotoxic activity
- Facile, polyherbal drug-mediated green synthesis of CuO nanoparticles and their potent biological applications
- Zinc oxide-manganese oxide/carboxymethyl cellulose-folic acid-sesamol hybrid nanomaterials: A molecularly targeted strategy for advanced triple-negative breast cancer therapy
- Exploring the antimicrobial potential of biogenically synthesized graphene oxide nanoparticles against targeted bacterial and fungal pathogens
- Biofabrication of silver nanoparticles using Uncaria tomentosa L.: Insight into characterization, antibacterial activities combined with antibiotics, and effect on Triticum aestivum germination
- Membrane distillation of synthetic urine for use in space structural habitat systems
- Investigation on mechanical properties of the green synthesis bamboo fiber/eggshell/coconut shell powder-based hybrid biocomposites under NaOH conditions
- Green synthesis of magnesium oxide nanoparticles using endophytic fungal strain to improve the growth, metabolic activities, yield traits, and phenolic compounds content of Nigella sativa L.
- Estimation of greenhouse gas emissions from rice and annual upland crops in Red River Delta of Vietnam using the denitrification–decomposition model
- Synthesis of humic acid with the obtaining of potassium humate based on coal waste from the Lenger deposit, Kazakhstan
- Ascorbic acid-mediated selenium nanoparticles as potential antihyperuricemic, antioxidant, anticoagulant, and thrombolytic agents
- Green synthesis of silver nanoparticles using Illicium verum extract: Optimization and characterization for biomedical applications
- Antibacterial and dynamical behaviour of silicon nanoparticles influenced sustainable waste flax fibre-reinforced epoxy composite for biomedical application
- Optimising coagulation/flocculation using response surface methodology and application of floc in biofertilisation
- Green synthesis and multifaceted characterization of iron oxide nanoparticles derived from Senna bicapsularis for enhanced in vitro and in vivo biological investigation
- Potent antibacterial nanocomposites from okra mucilage/chitosan/silver nanoparticles for multidrug-resistant Salmonella Typhimurium eradication
- Trachyspermum copticum aqueous seed extract-derived silver nanoparticles: Exploration of their structural characterization and comparative antibacterial performance against gram-positive and gram-negative bacteria
- Microwave-assisted ultrafine silver nanoparticle synthesis using Mitragyna speciosa for antimalarial applications
- Green synthesis and characterisation of spherical structure Ag/Fe2O3/TiO2 nanocomposite using acacia in the presence of neem and tulsi oils
- Green quantitative methods for linagliptin and empagliflozin in dosage forms
- Enhancement efficacy of omeprazole by conjugation with silver nanoparticles as a urease inhibitor
- Residual, sequential extraction, and ecological risk assessment of some metals in ash from municipal solid waste incineration, Vietnam
- Green synthesis of ZnO nanoparticles using the mangosteen (Garcinia mangostana L.) leaf extract: Comparative preliminary in vitro antibacterial study
- Simultaneous determination of lesinurad and febuxostat in commercial fixed-dose combinations using a greener normal-phase HPTLC method
- A greener RP-HPLC method for quaternary estimation of caffeine, paracetamol, levocetirizine, and phenylephrine acquiring AQbD with stability studies
- Optimization of biomass durian peel as a heterogeneous catalyst in biodiesel production using microwave irradiation
- Thermal treatment impact on the evolution of active phases in layered double hydroxide-based ZnCr photocatalysts: Photodegradation and antibacterial performance
- Preparation of silymarin-loaded zein polysaccharide core–shell nanostructures and evaluation of their biological potentials
- Preparation and characterization of composite-modified PA6 fiber for spectral heating and heat storage applications
- Preparation and electrocatalytic oxygen evolution of bimetallic phosphates (NiFe)2P/NF
- Rod-shaped Mo(vi) trichalcogenide–Mo(vi) oxide decorated on poly(1-H pyrrole) as a promising nanocomposite photoelectrode for green hydrogen generation from sewage water with high efficiency
- Green synthesis and studies on citrus medica leaf extract-mediated Au–ZnO nanocomposites: A sustainable approach for efficient photocatalytic degradation of rhodamine B dye in aqueous media
- Cellulosic materials for the removal of ciprofloxacin from aqueous environments
- The analytical assessment of metal contamination in industrial soils of Saudi Arabia using the inductively coupled plasma technology
- The effect of modified oily sludge on the slurry ability and combustion performance of coal water slurry
- Eggshell waste transformation to calcium chloride anhydride as food-grade additive and eggshell membranes as enzyme immobilization carrier
- Synthesis of EPAN and applications in the encapsulation of potassium humate
- Biosynthesis and characterization of silver nanoparticles from Cedrela toona leaf extracts: An exploration into their antibacterial, anticancer, and antioxidant potential
- Enhancing mechanical and rheological properties of HDPE films through annealing for eco-friendly agricultural applications
- Immobilisation of catalase purified from mushroom (Hydnum repandum) onto glutaraldehyde-activated chitosan and characterisation: Its application for the removal of hydrogen peroxide from artificial wastewater
- Sodium titanium oxide/zinc oxide (STO/ZnO) photocomposites for efficient dye degradation applications
- Effect of ex situ, eco-friendly ZnONPs incorporating green synthesised Moringa oleifera leaf extract in enhancing biochemical and molecular aspects of Vicia faba L. under salt stress
- Biosynthesis and characterization of selenium and silver nanoparticles using Trichoderma viride filtrate and their impact on Culex pipiens
- Photocatalytic degradation of organic dyes and biological potentials of biogenic zinc oxide nanoparticles synthesized using the polar extract of Cyperus scariosus R.Br. (Cyperaceae)
- Assessment of antiproliferative activity of green-synthesized nickel oxide nanoparticles against glioblastoma cells using Terminalia chebula
- Chlorine-free synthesis of phosphinic derivatives by change in the P-function
- Anticancer, antioxidant, and antimicrobial activities of nanoemulsions based on water-in-olive oil and loaded on biogenic silver nanoparticles
- Study and mechanism of formation of phosphorus production waste in Kazakhstan
- Synthesis and stabilization of anatase form of biomimetic TiO2 nanoparticles for enhancing anti-tumor potential
- Microwave-supported one-pot reaction for the synthesis of 5-alkyl/arylidene-2-(morpholin/thiomorpholin-4-yl)-1,3-thiazol-4(5H)-one derivatives over MgO solid base
- Screening the phytochemicals in Perilla leaves and phytosynthesis of bioactive silver nanoparticles for potential antioxidant and wound-healing application
- Graphene oxide/chitosan/manganese/folic acid-brucine functionalized nanocomposites show anticancer activity against liver cancer cells
- Nature of serpentinite interactions with low-concentration sulfuric acid solutions
- Multi-objective statistical optimisation utilising response surface methodology to predict engine performance using biofuels from waste plastic oil in CRDi engines
- Microwave-assisted extraction of acetosolv lignin from sugarcane bagasse and electrospinning of lignin/PEO nanofibres for carbon fibre production
- Biosynthesis, characterization, and investigation of cytotoxic activities of selenium nanoparticles utilizing Limosilactobacillus fermentum
- Highly photocatalytic materials based on the decoration of poly(O-chloroaniline) with molybdenum trichalcogenide oxide for green hydrogen generation from Red Sea water
- Highly efficient oil–water separation using superhydrophobic cellulose aerogels derived from corn straw
- Beta-cyclodextrin–Phyllanthus emblica emulsion for zinc oxide nanoparticles: Characteristics and photocatalysis
- Assessment of antimicrobial activity and methyl orange dye removal by Klebsiella pneumoniae-mediated silver nanoparticles
- Influential eradication of resistant Salmonella Typhimurium using bioactive nanocomposites from chitosan and radish seed-synthesized nanoselenium
- Antimicrobial activities and neuroprotective potential for Alzheimer’s disease of pure, Mn, Co, and Al-doped ZnO ultra-small nanoparticles
- Green synthesis of silver nanoparticles from Bauhinia variegata and their biological applications
- Synthesis and optimization of long-chain fatty acids via the oxidation of long-chain fatty alcohols
- Eminent Red Sea water hydrogen generation via a Pb(ii)-iodide/poly(1H-pyrrole) nanocomposite photocathode
- Green synthesis and effective genistein production by fungal β-glucosidase immobilized on Al2O3 nanocrystals synthesized in Cajanus cajan L. (Millsp.) leaf extracts
- Green stability-indicating RP-HPTLC technique for determining croconazole hydrochloride
- Green synthesis of La2O3–LaPO4 nanocomposites using Charybdis natator for DNA binding, cytotoxic, catalytic, and luminescence applications
- Eco-friendly drugs induce cellular changes in colistin-resistant bacteria
- Tangerine fruit peel extract mediated biogenic synthesized silver nanoparticles and their potential antimicrobial, antioxidant, and cytotoxic assessments
- Green synthesis on performance characteristics of a direct injection diesel engine using sandbox seed oil
- A highly sensitive β-AKBA-Ag-based fluorescent “turn off” chemosensor for rapid detection of abamectin in tomatoes
- Green synthesis and physical characterization of zinc oxide nanoparticles (ZnO NPs) derived from the methanol extract of Euphorbia dracunculoides Lam. (Euphorbiaceae) with enhanced biosafe applications
- Detection of morphine and data processing using surface plasmon resonance imaging sensor
- Effects of nanoparticles on the anaerobic digestion properties of sulfamethoxazole-containing chicken manure and analysis of bio-enzymes
- Bromic acid-thiourea synergistic leaching of sulfide gold ore
- Green chemistry approach to synthesize titanium dioxide nanoparticles using Fagonia Cretica extract, novel strategy for developing antimicrobial and antidiabetic therapies
- Green synthesis and effective utilization of biogenic Al2O3-nanocoupled fungal lipase in the resolution of active homochiral 2-octanol and its immobilization via aluminium oxide nanoparticles
- Eco-friendly RP-HPLC approach for simultaneously estimating the promising combination of pentoxifylline and simvastatin in therapeutic potential for breast cancer: Appraisal of greenness, whiteness, and Box–Behnken design
- Use of a humidity adsorbent derived from cockleshell waste in Thai fried fish crackers (Keropok)
- One-pot green synthesis, biological evaluation, and in silico study of pyrazole derivatives obtained from chalcones
- Bio-sorption of methylene blue and production of biofuel by brown alga Cystoseira sp. collected from Neom region, Kingdom of Saudi Arabia
- Synthesis of motexafin gadolinium: A promising radiosensitizer and imaging agent for cancer therapy
- The impact of varying sizes of silver nanoparticles on the induction of cellular damage in Klebsiella pneumoniae involving diverse mechanisms
- Microwave-assisted green synthesis, characterization, and in vitro antibacterial activity of NiO nanoparticles obtained from lemon peel extract
- Rhus microphylla-mediated biosynthesis of copper oxide nanoparticles for enhanced antibacterial and antibiofilm efficacy
- Harnessing trichalcogenide–molybdenum(vi) sulfide and molybdenum(vi) oxide within poly(1-amino-2-mercaptobenzene) frameworks as a photocathode for sustainable green hydrogen production from seawater without sacrificial agents
- Magnetically recyclable Fe3O4@SiO2 supported phosphonium ionic liquids for efficient and sustainable transformation of CO2 into oxazolidinones
- A comparative study of Fagonia arabica fabricated silver sulfide nanoparticles (Ag2S) and silver nanoparticles (AgNPs) with distinct antimicrobial, anticancer, and antioxidant properties
- Visible light photocatalytic degradation and biological activities of Aegle marmelos-mediated cerium oxide nanoparticles
- Physical intrinsic characteristics of spheroidal particles in coal gasification fine slag
- Exploring the effect of tea dust magnetic biochar on agricultural crops grown in polycyclic aromatic hydrocarbon contaminated soil
- Crosslinked chitosan-modified ultrafiltration membranes for efficient surface water treatment and enhanced anti-fouling performances
- Study on adsorption characteristics of biochars and their modified biochars for removal of organic dyes from aqueous solution
- Zein polymer nanocarrier for Ocimum basilicum var. purpurascens extract: Potential biomedical use
- Green synthesis, characterization, and in vitro and in vivo biological screening of iron oxide nanoparticles (Fe3O4) generated with hydroalcoholic extract of aerial parts of Euphorbia milii
- Novel microwave-based green approach for the synthesis of dual-loaded cyclodextrin nanosponges: Characterization, pharmacodynamics, and pharmacokinetics evaluation
- Bi2O3–BiOCl/poly-m-methyl aniline nanocomposite thin film for broad-spectrum light-sensing
- Green synthesis and characterization of CuO/ZnO nanocomposite using Musa acuminata leaf extract for cytotoxic studies on colorectal cancer cells (HCC2998)
- Review Articles
- Materials-based drug delivery approaches: Recent advances and future perspectives
- A review of thermal treatment for bamboo and its composites
- An overview of the role of nanoherbicides in tackling challenges of weed management in wheat: A novel approach
- An updated review on carbon nanomaterials: Types, synthesis, functionalization and applications, degradation and toxicity
- Special Issue: Emerging green nanomaterials for sustainable waste management and biomedical applications
- Green synthesis of silver nanoparticles using mature-pseudostem extracts of Alpinia nigra and their bioactivities
- Special Issue: New insights into nanopythotechnology: current trends and future prospects
- Green synthesis of FeO nanoparticles from coffee and its application for antibacterial, antifungal, and anti-oxidation activity
- Dye degradation activity of biogenically synthesized Cu/Fe/Ag trimetallic nanoparticles
- Special Issue: Composites and green composites
- Recent trends and advancements in the utilization of green composites and polymeric nanocarriers for enhancing food quality and sustainable processing
- Retraction
- Retraction of “Biosynthesis and characterization of silver nanoparticles from Cedrela toona leaf extracts: An exploration into their antibacterial, anticancer, and antioxidant potential”
- Retraction of “Photocatalytic degradation of organic dyes and biological potentials of biogenic zinc oxide nanoparticles synthesized using the polar extract of Cyperus scariosus R.Br. (Cyperaceae)”
- Retraction to “Green synthesis on performance characteristics of a direct injection diesel engine using sandbox seed oil”
Artikel in diesem Heft
- Research Articles
- Green polymer electrolyte and activated charcoal-based supercapacitor for energy harvesting application: Electrochemical characteristics
- Research on the adsorption of Co2+ ions using halloysite clay and the ability to recover them by electrodeposition method
- Simultaneous estimation of ibuprofen, caffeine, and paracetamol in commercial products using a green reverse-phase HPTLC method
- Isolation, screening and optimization of alkaliphilic cellulolytic fungi for production of cellulase
- Functionalized gold nanoparticles coated with bacterial alginate and their antibacterial and anticancer activities
- Comparative analysis of bio-based amino acid surfactants obtained via Diels–Alder reaction of cyclic anhydrides
- Biosynthesis of silver nanoparticles on yellow phosphorus slag and its application in organic coatings
- Exploring antioxidant potential and phenolic compound extraction from Vitis vinifera L. using ultrasound-assisted extraction
- Manganese and copper-coated nickel oxide nanoparticles synthesized from Carica papaya leaf extract induce antimicrobial activity and breast cancer cell death by triggering mitochondrial caspases and p53
- Insight into heating method and Mozafari method as green processing techniques for the synthesis of micro- and nano-drug carriers
- Silicotungstic acid supported on Bi-based MOF-derived metal oxide for photodegradation of organic dyes
- Synthesis and characterization of capsaicin nanoparticles: An attempt to enhance its bioavailability and pharmacological actions
- Synthesis of Lawsonia inermis-encased silver–copper bimetallic nanoparticles with antioxidant, antibacterial, and cytotoxic activity
- Facile, polyherbal drug-mediated green synthesis of CuO nanoparticles and their potent biological applications
- Zinc oxide-manganese oxide/carboxymethyl cellulose-folic acid-sesamol hybrid nanomaterials: A molecularly targeted strategy for advanced triple-negative breast cancer therapy
- Exploring the antimicrobial potential of biogenically synthesized graphene oxide nanoparticles against targeted bacterial and fungal pathogens
- Biofabrication of silver nanoparticles using Uncaria tomentosa L.: Insight into characterization, antibacterial activities combined with antibiotics, and effect on Triticum aestivum germination
- Membrane distillation of synthetic urine for use in space structural habitat systems
- Investigation on mechanical properties of the green synthesis bamboo fiber/eggshell/coconut shell powder-based hybrid biocomposites under NaOH conditions
- Green synthesis of magnesium oxide nanoparticles using endophytic fungal strain to improve the growth, metabolic activities, yield traits, and phenolic compounds content of Nigella sativa L.
- Estimation of greenhouse gas emissions from rice and annual upland crops in Red River Delta of Vietnam using the denitrification–decomposition model
- Synthesis of humic acid with the obtaining of potassium humate based on coal waste from the Lenger deposit, Kazakhstan
- Ascorbic acid-mediated selenium nanoparticles as potential antihyperuricemic, antioxidant, anticoagulant, and thrombolytic agents
- Green synthesis of silver nanoparticles using Illicium verum extract: Optimization and characterization for biomedical applications
- Antibacterial and dynamical behaviour of silicon nanoparticles influenced sustainable waste flax fibre-reinforced epoxy composite for biomedical application
- Optimising coagulation/flocculation using response surface methodology and application of floc in biofertilisation
- Green synthesis and multifaceted characterization of iron oxide nanoparticles derived from Senna bicapsularis for enhanced in vitro and in vivo biological investigation
- Potent antibacterial nanocomposites from okra mucilage/chitosan/silver nanoparticles for multidrug-resistant Salmonella Typhimurium eradication
- Trachyspermum copticum aqueous seed extract-derived silver nanoparticles: Exploration of their structural characterization and comparative antibacterial performance against gram-positive and gram-negative bacteria
- Microwave-assisted ultrafine silver nanoparticle synthesis using Mitragyna speciosa for antimalarial applications
- Green synthesis and characterisation of spherical structure Ag/Fe2O3/TiO2 nanocomposite using acacia in the presence of neem and tulsi oils
- Green quantitative methods for linagliptin and empagliflozin in dosage forms
- Enhancement efficacy of omeprazole by conjugation with silver nanoparticles as a urease inhibitor
- Residual, sequential extraction, and ecological risk assessment of some metals in ash from municipal solid waste incineration, Vietnam
- Green synthesis of ZnO nanoparticles using the mangosteen (Garcinia mangostana L.) leaf extract: Comparative preliminary in vitro antibacterial study
- Simultaneous determination of lesinurad and febuxostat in commercial fixed-dose combinations using a greener normal-phase HPTLC method
- A greener RP-HPLC method for quaternary estimation of caffeine, paracetamol, levocetirizine, and phenylephrine acquiring AQbD with stability studies
- Optimization of biomass durian peel as a heterogeneous catalyst in biodiesel production using microwave irradiation
- Thermal treatment impact on the evolution of active phases in layered double hydroxide-based ZnCr photocatalysts: Photodegradation and antibacterial performance
- Preparation of silymarin-loaded zein polysaccharide core–shell nanostructures and evaluation of their biological potentials
- Preparation and characterization of composite-modified PA6 fiber for spectral heating and heat storage applications
- Preparation and electrocatalytic oxygen evolution of bimetallic phosphates (NiFe)2P/NF
- Rod-shaped Mo(vi) trichalcogenide–Mo(vi) oxide decorated on poly(1-H pyrrole) as a promising nanocomposite photoelectrode for green hydrogen generation from sewage water with high efficiency
- Green synthesis and studies on citrus medica leaf extract-mediated Au–ZnO nanocomposites: A sustainable approach for efficient photocatalytic degradation of rhodamine B dye in aqueous media
- Cellulosic materials for the removal of ciprofloxacin from aqueous environments
- The analytical assessment of metal contamination in industrial soils of Saudi Arabia using the inductively coupled plasma technology
- The effect of modified oily sludge on the slurry ability and combustion performance of coal water slurry
- Eggshell waste transformation to calcium chloride anhydride as food-grade additive and eggshell membranes as enzyme immobilization carrier
- Synthesis of EPAN and applications in the encapsulation of potassium humate
- Biosynthesis and characterization of silver nanoparticles from Cedrela toona leaf extracts: An exploration into their antibacterial, anticancer, and antioxidant potential
- Enhancing mechanical and rheological properties of HDPE films through annealing for eco-friendly agricultural applications
- Immobilisation of catalase purified from mushroom (Hydnum repandum) onto glutaraldehyde-activated chitosan and characterisation: Its application for the removal of hydrogen peroxide from artificial wastewater
- Sodium titanium oxide/zinc oxide (STO/ZnO) photocomposites for efficient dye degradation applications
- Effect of ex situ, eco-friendly ZnONPs incorporating green synthesised Moringa oleifera leaf extract in enhancing biochemical and molecular aspects of Vicia faba L. under salt stress
- Biosynthesis and characterization of selenium and silver nanoparticles using Trichoderma viride filtrate and their impact on Culex pipiens
- Photocatalytic degradation of organic dyes and biological potentials of biogenic zinc oxide nanoparticles synthesized using the polar extract of Cyperus scariosus R.Br. (Cyperaceae)
- Assessment of antiproliferative activity of green-synthesized nickel oxide nanoparticles against glioblastoma cells using Terminalia chebula
- Chlorine-free synthesis of phosphinic derivatives by change in the P-function
- Anticancer, antioxidant, and antimicrobial activities of nanoemulsions based on water-in-olive oil and loaded on biogenic silver nanoparticles
- Study and mechanism of formation of phosphorus production waste in Kazakhstan
- Synthesis and stabilization of anatase form of biomimetic TiO2 nanoparticles for enhancing anti-tumor potential
- Microwave-supported one-pot reaction for the synthesis of 5-alkyl/arylidene-2-(morpholin/thiomorpholin-4-yl)-1,3-thiazol-4(5H)-one derivatives over MgO solid base
- Screening the phytochemicals in Perilla leaves and phytosynthesis of bioactive silver nanoparticles for potential antioxidant and wound-healing application
- Graphene oxide/chitosan/manganese/folic acid-brucine functionalized nanocomposites show anticancer activity against liver cancer cells
- Nature of serpentinite interactions with low-concentration sulfuric acid solutions
- Multi-objective statistical optimisation utilising response surface methodology to predict engine performance using biofuels from waste plastic oil in CRDi engines
- Microwave-assisted extraction of acetosolv lignin from sugarcane bagasse and electrospinning of lignin/PEO nanofibres for carbon fibre production
- Biosynthesis, characterization, and investigation of cytotoxic activities of selenium nanoparticles utilizing Limosilactobacillus fermentum
- Highly photocatalytic materials based on the decoration of poly(O-chloroaniline) with molybdenum trichalcogenide oxide for green hydrogen generation from Red Sea water
- Highly efficient oil–water separation using superhydrophobic cellulose aerogels derived from corn straw
- Beta-cyclodextrin–Phyllanthus emblica emulsion for zinc oxide nanoparticles: Characteristics and photocatalysis
- Assessment of antimicrobial activity and methyl orange dye removal by Klebsiella pneumoniae-mediated silver nanoparticles
- Influential eradication of resistant Salmonella Typhimurium using bioactive nanocomposites from chitosan and radish seed-synthesized nanoselenium
- Antimicrobial activities and neuroprotective potential for Alzheimer’s disease of pure, Mn, Co, and Al-doped ZnO ultra-small nanoparticles
- Green synthesis of silver nanoparticles from Bauhinia variegata and their biological applications
- Synthesis and optimization of long-chain fatty acids via the oxidation of long-chain fatty alcohols
- Eminent Red Sea water hydrogen generation via a Pb(ii)-iodide/poly(1H-pyrrole) nanocomposite photocathode
- Green synthesis and effective genistein production by fungal β-glucosidase immobilized on Al2O3 nanocrystals synthesized in Cajanus cajan L. (Millsp.) leaf extracts
- Green stability-indicating RP-HPTLC technique for determining croconazole hydrochloride
- Green synthesis of La2O3–LaPO4 nanocomposites using Charybdis natator for DNA binding, cytotoxic, catalytic, and luminescence applications
- Eco-friendly drugs induce cellular changes in colistin-resistant bacteria
- Tangerine fruit peel extract mediated biogenic synthesized silver nanoparticles and their potential antimicrobial, antioxidant, and cytotoxic assessments
- Green synthesis on performance characteristics of a direct injection diesel engine using sandbox seed oil
- A highly sensitive β-AKBA-Ag-based fluorescent “turn off” chemosensor for rapid detection of abamectin in tomatoes
- Green synthesis and physical characterization of zinc oxide nanoparticles (ZnO NPs) derived from the methanol extract of Euphorbia dracunculoides Lam. (Euphorbiaceae) with enhanced biosafe applications
- Detection of morphine and data processing using surface plasmon resonance imaging sensor
- Effects of nanoparticles on the anaerobic digestion properties of sulfamethoxazole-containing chicken manure and analysis of bio-enzymes
- Bromic acid-thiourea synergistic leaching of sulfide gold ore
- Green chemistry approach to synthesize titanium dioxide nanoparticles using Fagonia Cretica extract, novel strategy for developing antimicrobial and antidiabetic therapies
- Green synthesis and effective utilization of biogenic Al2O3-nanocoupled fungal lipase in the resolution of active homochiral 2-octanol and its immobilization via aluminium oxide nanoparticles
- Eco-friendly RP-HPLC approach for simultaneously estimating the promising combination of pentoxifylline and simvastatin in therapeutic potential for breast cancer: Appraisal of greenness, whiteness, and Box–Behnken design
- Use of a humidity adsorbent derived from cockleshell waste in Thai fried fish crackers (Keropok)
- One-pot green synthesis, biological evaluation, and in silico study of pyrazole derivatives obtained from chalcones
- Bio-sorption of methylene blue and production of biofuel by brown alga Cystoseira sp. collected from Neom region, Kingdom of Saudi Arabia
- Synthesis of motexafin gadolinium: A promising radiosensitizer and imaging agent for cancer therapy
- The impact of varying sizes of silver nanoparticles on the induction of cellular damage in Klebsiella pneumoniae involving diverse mechanisms
- Microwave-assisted green synthesis, characterization, and in vitro antibacterial activity of NiO nanoparticles obtained from lemon peel extract
- Rhus microphylla-mediated biosynthesis of copper oxide nanoparticles for enhanced antibacterial and antibiofilm efficacy
- Harnessing trichalcogenide–molybdenum(vi) sulfide and molybdenum(vi) oxide within poly(1-amino-2-mercaptobenzene) frameworks as a photocathode for sustainable green hydrogen production from seawater without sacrificial agents
- Magnetically recyclable Fe3O4@SiO2 supported phosphonium ionic liquids for efficient and sustainable transformation of CO2 into oxazolidinones
- A comparative study of Fagonia arabica fabricated silver sulfide nanoparticles (Ag2S) and silver nanoparticles (AgNPs) with distinct antimicrobial, anticancer, and antioxidant properties
- Visible light photocatalytic degradation and biological activities of Aegle marmelos-mediated cerium oxide nanoparticles
- Physical intrinsic characteristics of spheroidal particles in coal gasification fine slag
- Exploring the effect of tea dust magnetic biochar on agricultural crops grown in polycyclic aromatic hydrocarbon contaminated soil
- Crosslinked chitosan-modified ultrafiltration membranes for efficient surface water treatment and enhanced anti-fouling performances
- Study on adsorption characteristics of biochars and their modified biochars for removal of organic dyes from aqueous solution
- Zein polymer nanocarrier for Ocimum basilicum var. purpurascens extract: Potential biomedical use
- Green synthesis, characterization, and in vitro and in vivo biological screening of iron oxide nanoparticles (Fe3O4) generated with hydroalcoholic extract of aerial parts of Euphorbia milii
- Novel microwave-based green approach for the synthesis of dual-loaded cyclodextrin nanosponges: Characterization, pharmacodynamics, and pharmacokinetics evaluation
- Bi2O3–BiOCl/poly-m-methyl aniline nanocomposite thin film for broad-spectrum light-sensing
- Green synthesis and characterization of CuO/ZnO nanocomposite using Musa acuminata leaf extract for cytotoxic studies on colorectal cancer cells (HCC2998)
- Review Articles
- Materials-based drug delivery approaches: Recent advances and future perspectives
- A review of thermal treatment for bamboo and its composites
- An overview of the role of nanoherbicides in tackling challenges of weed management in wheat: A novel approach
- An updated review on carbon nanomaterials: Types, synthesis, functionalization and applications, degradation and toxicity
- Special Issue: Emerging green nanomaterials for sustainable waste management and biomedical applications
- Green synthesis of silver nanoparticles using mature-pseudostem extracts of Alpinia nigra and their bioactivities
- Special Issue: New insights into nanopythotechnology: current trends and future prospects
- Green synthesis of FeO nanoparticles from coffee and its application for antibacterial, antifungal, and anti-oxidation activity
- Dye degradation activity of biogenically synthesized Cu/Fe/Ag trimetallic nanoparticles
- Special Issue: Composites and green composites
- Recent trends and advancements in the utilization of green composites and polymeric nanocarriers for enhancing food quality and sustainable processing
- Retraction
- Retraction of “Biosynthesis and characterization of silver nanoparticles from Cedrela toona leaf extracts: An exploration into their antibacterial, anticancer, and antioxidant potential”
- Retraction of “Photocatalytic degradation of organic dyes and biological potentials of biogenic zinc oxide nanoparticles synthesized using the polar extract of Cyperus scariosus R.Br. (Cyperaceae)”
- Retraction to “Green synthesis on performance characteristics of a direct injection diesel engine using sandbox seed oil”
