Startseite Combating paraben pollution in surface waters with a variety of photocatalyzed systems: Looking for the most efficient technology
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Combating paraben pollution in surface waters with a variety of photocatalyzed systems: Looking for the most efficient technology

  • Joaquin R. Dominguez EMAIL logo , Teresa Gonzalez , Eduardo M. Cuerda-Correa und Maria J. Muñoz-Peña
Veröffentlicht/Copyright: 31. Dezember 2019
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Open Chemistry
Aus der Zeitschrift Open Chemistry Band 17 Heft 1

Abstract

The constant presence of parabens in natural surface waters has raised a growing concern of the potential long-term toxic effects that parabens may have in wildlife, mainly as endocrine disruptors. The present report describes the results of a study in which different photocatalyzed systems, such as photo-Fenton, Fenton, UV-H2O2, UV-TiO2 and UV-TiO2-H2O2, were applied to the removal of these recalcitrant pollutants in some surface waters, including natural (e.g. rivers) and man-made (e.g. reservoirs and wastewater treatment plants). Degradation of four widely-used parabens (methyl-paraben, ethyl-paraben, propyl-paraben and butyl-paraben) was analyzed. Experimental results reveal that the most efficient method to combat these emerging pollutants was photo-Fenton. When this process was optimized, optimal removal efficiency was attained using doses of H2O2 and Fe(II) equal to 2.92·10−4 mol dm-3 and 1.85·10−5 mol dm-3, respectively. It is also worth noting that the removal rate of these contaminants is slower in natural waters. The results suggest that the photo-Fenton process is promising and maybe an adequate technology for the treatment of these persistent contaminants.

Keywords: Water Treatment; Surface-waters; Parabens pollution; photo-assisted Fenton; Remediation Systems

1 Introduction

The detection of emerging contaminants (ECs) in the environment has been of increasing interest [1, 2]. This group of pollutants includes personal care products, hormones, disinfectants, surfactant, and gasoline additives, among others [3]. One of the most important characteristics of ECs that makes them such critical threats to the environment is that many of them cannot be completely degraded through conventional treatments. Therefore, the development of new technologies is needed. Among emerging technologies, advanced oxidation processes (AOPs) provide a promising option for the treatment of ECs [4].

The impact on human and animal health of many substances that are present in the environment is not yet fully known [5]. Such is especially the case with parabens, a seemingly innocuous family of preservatives whose relationships with certain allergies [6], irritation of skin and eyes [7], a decrease of male fertility [8] and even breast cancer [9] have been reported over the past few years. Furthermore, parabens are among the most commonly found of the emerging pollutants, and their presence in ground- and surface water has been increasingly detected.

The most common parabens detected in natural waters are methyl-paraben (MP), ethyl-paraben (EP), propyl-paraben (PP) and butyl-paraben (BP). Currently, parabens are most commonly used as preservatives in the cosmetic industry [10], and they have also been used in pharmaceuticals, foodstuffs and other industrial products. Until the late 1990s, only a few studies had reported on the potentially harmful effects of parabens on both human health and the environment. Nowadays, however, the number of scientific studies warning about the effects of parabens on human health and the environment is increasing remarkably. The toxicity of parabens is closely related to their activity as hormone disruptors: for example, several recent studies have demonstrated relationships between breast cancer and the presence of parabens in tumour tissues [11, 12, 13]. Researchers studying the causes of breast cancer [12] confirmed that parabens are readily absorbed into the body.

The detection of parabens in human tissues from environmental exposures has also been recently reported [11]. Parabens have also been detected in human urine, in human milk, human serum, and human seminal fluid [14, 15, 16, 17, 18, 19, 20, 21]. Parabens may be present in different types of water, including swimming pool water or seawater, albeit there are very few data on the presence of parabens in drinking water. In the United States, a study from four sources of treated drinking water reported that MP was undetectable [22]. On the contrary, in Spain, the presence of MP in tap water has been reported [23, 24]; however, these authors did not investigate the presence of other parabens, such as EP, PP and BP. More recently, the presence of MP, PP and BP was found in tap water, although in this case, EP was undetectable [25].

The presence of parabens in inland waters can be largely attributed to discharges from sewage treatment plants and factories. Different areas of several rivers have been sampled, and large variations in the concentrations of parabens depending on the zone were demonstrated. Such concentrations have been linked to the presence of effluent discharge or industrial activities [25, 26, 27, 28, 29].

In summary, it can be stated that parabens are ubiquitous pollutants in surface waters. Since parabens were detected in wastewater treatment plants (WWTP) effluents, rivers and reservoirs, and even in drinking water, the implementation of more efficient degradation processes is a topic of current interest. Due to their cost efficiency and simplicity, AOPs appear to be excellent choices for the complete degradation of this kind of pollutant in aqueous media. Among them, chemical advanced oxidation processes are particularly useful for the removal of toxic or biologically non-degradable pollutants, such as aromatic compounds, dyes, pesticides, and volatile organic compounds present in wastewater [4, 30, 31, 32, 33, 34] and surface waters [34, 35, 36], although their widespread application is limited and depends on operation costs.

In particular, photo-assisted AOPs have been used for the removal of persistent pollutants from aqueous matrices. Among these photo-assisted AOPs, the photo-Fenton process constitutes an excellent choice due to its high effectiveness and relatively low cost. Furthermore, this kind of process makes it possible to achieve complete destruction of pollutants to harmless compounds, such as carbon dioxide and water [37]. All of these processes are based on the generation of reactive species (such as hydroxyl radical), which oxidize a wide variety of contaminants in a rapid and non-selective manner.

The basis of the photo-assisted Fenton process consists of hydrogen peroxide decomposition in acidic medium, catalyzed by iron (II) ions, giving rise to the strongly oxidizing ·OH radical. This system consists of three steps:

  1. Photolysis of hydrogen peroxide [38]:

(1)H2O2+hv→2⋅OH

  1. The reaction of Fe(II) ions with hydrogen peroxide:

(2)Fe2++H2O2→FeOH2++⋅OH

  1. Reduction of Fe(III) ions to Fe(II) ions:

(3)FeOH2++hv→Fe2++⋅OH

Therefore, the UV radiation accelerates the cycle Fe(II)-Fe(III)-Fe(II), thus facilitating the production of hydroxyl radicals. Hydroperoxyl radicals are also generated according to the following reaction:

(4)H2O2+⋅OH→HO2⋅+H2O

Bossmann et al. [39] proposed that the ferric ion in the presence of UV radiation evolves to an excited state (Fe3+*) that reacts faster with the hydrogen peroxide to form Fe2+ (Eq. (5)), or with organic compounds in its elemental state.

(5)Fe3++H2O2→Fe2++H++HO2⋅

Analysis of the process described above suggests that the photo-Fenton process is adequate to be applied in water purification treatments since strongly oxidizing hydroxyl radicals are generated without the formation of potentially harmful chlorinated secondary oxidation products. This is an important advantage when compared with other traditional chemical oxidation processes that involve the use of chlorine or chlorine dioxide.

2 Materials

2.1 Chemicals

Methyl-paraben (CAS Number 99-76-3), ethyl-paraben (120-47-8), propyl-paraben (94-13-3), and butyl-paraben (94-26-8) were of the highest purity (>98%) and were purchased from Sigma (Spain). A stock solution of the four parabens (5 mg dm-3) was created with high purity water (from a Millipore Milli-QTM system). This initial concentration of parabens was selected in order to conform with a previous literature survey, which studied several experimental works that had the aim of removing parabens from WWTP influents or effluents [14]. The exact concentration of hydrogen peroxide (nominally 33% w/v, analytical grade, Sigma-Aldrich) was determined by a photometric method using Titanium (IV) oxysulfate-sulfuric acid solution (Fluka 89532) as reactant. FeSO4·7 H2O (99.9% analytical grade Sigma-Aldrich) was purchased from Merck (Spain), and the Fe2+ concentration was determined by permanganometry. TiO2 (Degussa P25) was purchased from Degussa Portugal (AEROXIDE®-P25).

Surface water aqueous matrices were obtained from the Guadiana River (Badajoz, SW Spain) (type I), the reservoir of Peña del Águila (Villar del Rey, Badajoz, SW Spain) (type II), and secondary WWTP-Badajoz effluent (type III). Table 1 shows the physicochemical characterization of these surface -aqueous matrices.

Table 1

Characterization of the different used surface-water aqueous matrices. Guadiana River (Badajoz, SW Spain), type I, reservoir of Peña del Águila (Villar del Rey, Badajoz, SW Spain), type II, and secondary WWTP-Badajoz effluent, type III.

Surface Water
Type IType IIType III
pH8.17.08.3
Conductivity, μS/cm415.0126.2550
Hardness, mg CaCO3/L180.038.0236.0
Alcalinity, mg/L84.024.0222.0
Ammonium, mg/L0.050.025.8
COD, mg/L27.518.037.0
TOC, mg/L8.06.713.0

2.2 Experimental

The reactor was filled with an aqueous solution containing the four parabens (5 mg dm-3). A total volume of 0.350 dm3 of the solution was used for all experiments, excepting Fenton (250 ml). Finally, in all cases, the reaction was stopped by addition of bisulfite at time intervals. In every experience involving UV radiation, the experiments were performed in a cylindrical glass and the reactor was equipped with an axial radiation source (Heraeus TNN 15/32 lamp, 15W, λ = 254 nm). The constant operating conditions for all the systems under study (based in our previous studies) were: [H2O2]=2.7·10-4 mol dm-3, [Fe2+]=2.7·10-5 mol dm-3 and [TiO2]=3.83·10-4 mol dm-3.

2.3 Analytical

MP, EP, PP and BP were determined by HPLC using a Waters HPLC chromatograph, equipped with a photodiode Array 996 detector and a Phenomenex-Pak C-18 column (5 μm, 150 mm x 3.9 mm). Well-defined peaks were obtained at 2.2, 2.8, 4.2 and 6.8 min for MP, EP, PP and BP, respectively. The mobile phase was a 60:40 methanol:water mixture (10−2 mol dm-3 orthophosphoric acid) in isocratic operation mode.

2.4 Design of experiments (DoE)

The removal efficiency of parabens after 30 minutes was considered as the response variable (Y). The operating levels of the statistical design of experiments (DoE) for the photo-Fenton process were: [H2O2]0 codified values (-1, +1) corresponds to (4.31·10-5 mol dm-3, 2.51·10-4 mol dm-3), respectively; in the case of [Fe2+]0 these codified values were (4.31·10-6 mol dm-3, 2.5·10-5 mol dm-3) respectively.

Ethical approval: The conducted research is not related to either human or animal use.

3 Results and discussion

3.1 Preliminary experiments

The generation of hydroxyl radicals in Fenton processes is strongly influenced by several factors, including pH and initial concentrations of the reagents (namely, H2O2 and Fe2+). Due to the scarce solubility of iron hydroxides, the pH range to be used in Fenton processes is restricted to values of 4.5 and below. Furthermore, according to the experience of the authors, optimum results are attained in terms of removal efficiency of this kind of compounds by using a [H2O2 ]0 : [F e2+]0 ratio equal to 10 [40, 41]. However, the selection of an adequate initial concentration of hydrogen peroxide is far from easy. Hence, in order to optimize the initial H2O2 concentration, a set of preliminary experiments were performed with [H2O2]0 ranging from 1.25·10−5 mol dm-3 to 2.50 ·10−4 mol dm-3.

The results of the preliminary trials with MP are shown in Figure 1. According to these results, it can be concluded that, as a rule, the removal efficiencies after 60 min of treatment are relatively low (at most, 54.9, 58.0 and 67.0%) for MP, EP and PP, respectively. For BP, on the contrary, up to 76.9% of removal is attained even using low initial concentrations of H2O2. For higher initial concentrations of this reagent, namely 1.25 and 2.50·10−5 mol dm-3, complete abatement of the parabens is achieved after 45-60 minutes of treatment. It is worth noting that above a given concentration of hydrogen peroxide no remarkable effect is observed in terms of removal efficiency of the pollutants with an increase in hydrogen peroxide concentration. This saturating effect is in good agreement with the fact that H2O2 may serve as a radical scavenger as suggested by Eq. (4) and the formation of hydroperoxyl radicals (HO2·), a chemical species with a lower oxidation potential than HO·.

Figure 1 MP removal efficiency (%) vs. time as at different initial concentrations of hydrogen peroxide. [MP]0=5 mgdm-3, [H2O2 ]0 : [F e2+]0 = 10. T=25 ⍛C.
Figure 1

MP removal efficiency (%) vs. time as at different initial concentrations of hydrogen peroxide. [MP]0=5 mgdm-3, [H2O2 ]0 : [F e2+]0 = 10. T=25 ⍛C.

Taking into consideration these results, an experimental design was planned using an initial H2O2 concentration of 1.25·10−5 mol dm-3 as the central point (0) and 2.50·10−5 mol dm-3 as the factorial point (+1).

3.2 Parabens abatement by several AOPs

The oxidation of the four pollutants, simultaneously in ultrapure water, was first performed with Fenton’s reagent (H2O2/Fe2+) and with the following AOPs that employ UV radiation: UV/ H2O2, UV/Fe2+/ H2O2 (photo-Fenton system), UV/TiO2 and UV/TiO2/H2O2. In order to perform a comparison of all of the AOPs here studied, the experimental conditions indicated in Section 3.1 were considered as optimal and consistently used in all cases.

The removal efficiencies for MP by all of the examined AOPs are shown in Figure 2. Similar results were obtained for EP, PP and BP (data not shown). It can be readily concluded that the photo-Fenton (UV/Fe2+/H2O2) ternary system yields the most effective process. The other ternary system (i.e., UV/TiO2/ H2O2) also exhibits removal efficiencies that are larger than those of the binary systems, i.e., Fenton (Fe2+/ H2O2), UV/ H2O2 and UV/TiO2, but in this case, the efficiencies are more similar to those of the binary systems. The sequence shown in Figure 2 suggests that, in combination with H2O2, Fe2+ is somewhat more efficient than TiO2. The synergistic effect observed for the photo-Fenton system is consistent with results obtained in the 1990s [42, 43, 44] and more recently by Serna-Galvis et al. [45]. Figure 2 confirms that UV radiation accelerates the Fenton process, thus improving the degradation of the parabens. A reasonable explanation for this result is the fact that during the reaction, Fe2+ oxidizes to Fe3+ (Eq. (2)) and that the regeneration of the ferrous ions occurs in a process that is mediated by UV radiation (Eq. (3)), thus facilitating the production of hydroxyl radicals (Eq. (4) and Eq. (5)).

Figure 2 Methylparaben removal efficiency (%) for the different AOPs. [MP]0=5 mg dm-3, [H2O2]0=2,7·10-4 mol dm-3, [Fe2+]=2,7·10-5 mol dm-3, [TiO2]0=0,38 ·10-3 mol dm-3, T=25 ⍛C. UV radiation source = Heraeus TNN 15/32 (15W).
Figure 2

Methylparaben removal efficiency (%) for the different AOPs. [MP]0=5 mg dm-3, [H2O2]0=2,7·10-4 mol dm-3, [Fe2+]=2,7·10-5 mol dm-3, [TiO2]0=0,38 ·10-3 mol dm-3, T=25 ⍛C. UV radiation source = Heraeus TNN 15/32 (15W).

Moreover, the Fenton system is more effective than UV/H2O2 because the hydroxyl radicals generated in this latter system by the photocatalytic degradation of H2O2 (Eq. (1)) are consumed during the reaction [46]. In the Fenton system, the rate of degradation of the contaminant increases, since the reaction of hydroxyl radical generation may still occur in the medium by the reduction of ferric ions to ferrous ions (Eq. (5)) in the presence of H2O2. Furthermore, titania catalyzes the reaction of the organic contaminant by photodegradation due to the intrinsic nature of its electrical structure [47] so that it facilitates the ·OH radical generation. However, the presence of H2O2 exerts an important influence on the photodegradation process of the organic compounds, because H2O2 acts as a powerful oxidant, generating large amounts of ·OH radicals [48]. In the UV/TiO2 process, the contribution of radical oxidation is very low, like that of the photooxidation process. However, in the UV/H2O2 process, oxidation by free radicals (especially ·OH) is much more remarkable due to the presence of H2O2 [49].

These results allow us to conclude that the photo-Fenton system is clearly the most effective process for the destruction of these pollutants. Therefore, this system was studied in more detail.

3.3 Photo-Fenton Experimental Design

Two operational variables (namely, A: [H2O2]0 and B: [Fe2+]0), their mutual interaction (AB), and their respective quadratic effects (A2 and B2) are considered in the ANOVA test. A nonlinear equation regression was performed (Eq. (6)) for each paraben compound.

(6)Y(%)=bo+a⋅[H2O2]o+b⋅[Fe2+]o+c⋅([H2O2]o)2+             +d⋅[H2O2]0⋅[Fe2+]o+e⋅([Fe2+]o)2

Table 2 shows the fitting coefficients obtained for the removal of the different parabens. The positive influences of [H2O2]0 and [Fe2+] are due to the fact that these variables positively impact the generation of ·OH radicals. The value of the correlation factor (R2) reaches 0.959, which is consistent with adequate modelling of the process.

Table 2

Fitting coefficients of eqn (6) obtained for each compound. Reaction time=30 min. Target variable = paraben removal percentage (%).

Compoundb0abcde
Methyl-paraben62.121.97.1-1.13-6.8-10.8
Ethyl-paraben67.922.45.32-2.27-0.58-10.1
Propyl-paraben7220.913-5.4-5.02-1.85
Buthyl-paraben8018.95.03-4.27-4.45-8.29

Table 3 lists the values of [H2O2]0 and [Fe2+]0 that optimize the removal of each contaminant separately. It can be clearly appreciated that, for all parabens, with respect to [Fe2+]0 an optimum for the separate removal has been found in the range of coded values comprised between 0.683 and 0.776 (excepting for propyl-paraben, 1.410). This corresponds to initial concentrations of 2.17·10−5 - 2.27·10−5 mol dm-3. However, for [H2O2]0, no optimum is predicted in this range. Nevertheless, the initial concentration of hydrogen peroxide should not be excessively increased due to the aforesaid scavenging effect. Table 3 also shows the coded and natural values of [H2O2]0 and [Fe2+]0 that optimize the removal of all contaminants simultaneously [50]. Operating under these conditions (i.e., [H2O2]0 = 2.92·10−4 mol dm-3 and [Fe2+]0 = 1.85·10−5 mol dm-3), total removal of the four compounds should be obtained.

Table 3

Optimal conditions. Coded and natural values. Reaction time=30 min. Target variable = paraben removal percentage.

Separateoptimization
CodedvaluesNaturalvalues, mol. L-1
Optimum Removal (%)[H2O2]0[Fe2+]0[H2O2]0[Fe2+]0
Methyl-paraben97.251.4140.7762.93x10-42.27x10-5
Ethyl-paraben100.001.4140.7262.93x10-42.22x10-5
Propyl-paraben100.001.4141.4102.93x10-42.92x10-5
Butyl-paraben100.001.4140.6832.93x10-42.17x10-5
Jointoptimization
100.001.3950.3632.92x10-41.85x10-5

3.3.1 Graphical analysis

A model was developed according to five factors, which correspond to Eq. (6). The so-called Pareto plot (Figure 5) may be considered as a plot of the results of the ANOVA test. Grey bars represent negative factors, and white bars correspond to positive factors.

The main effect plots allow us to conclude that [H2O2]0 represents a positive influence in this range of study. This fact is consistent with an increase in the formation of ·OH radicals. With respect to [Fe2+]0, in all cases except for PP, the curve shows a maximum. This suggests that the presence of ferrous ions favours the oxidation process due to the catalytic role of Fe2+, but only up to a coded value around 0.5-0.7. Larger coded values exert a negative effect on the removal of all compounds except for PP.

Figure 3 displays these results regarding BP degradation. The response surface is remarkably convex along with the whole operational range. Both variables (namely, [H2O2]0 and [Fe2+]0) affect the compound removal in a similar manner but only for [Fe2+]0 can an optimum be determined.

Figure 3 Response surface and contour plot for the removal of BP by photo-Fenton system. Influence of initial concentration of hydrogen peroxide and ferrous salt. T=25 ⍛C. [BP]0=5 mg dm-3
Figure 3

Response surface and contour plot for the removal of BP by photo-Fenton system. Influence of initial concentration of hydrogen peroxide and ferrous salt. T=25 ⍛C. [BP]0=5 mg dm-3

3.4 Influence of the aqueous matrix on the photo-Fenton system

With regard to the influence of the aqueous matrix, three different aqueous surface waters type I (Guadiana River), type II (Peña del Águila reservoir) and type III (Badajoz-WWTP effluent) were tested. Experiments were carried out at the previously determined optimal conditions for the Photo-Fenton process. Figure 4 shows the evolution of the EP removal vs. time in the four aqueous matrices (including Milli-Q ultrapure water). Similar results were obtained for MP, PP and BP. As can be seen, the removal efficiency follows the trend ultrapure water ≈ river water > WWTP effluent ≈ reservoir water. It can be stated that the removal is faster when ultrapure water is used, followed by river water and WWTP effluent. The removal of the parabens from reservoir water is very slow in all cases.

Figure 4 Ethyl-paraben removal in different aqueous matrices by the photo-Fenton process in optimal conditions [EP]0=5 mg dm-3, [H2O2]0 = 2.92·10−4 M and [Fe2+]0 = 1.85·10−5 M, T=25 ⍛C, Heraeus TNN 15/32 lamp, 15W, λ = 254 nm.
Figure 4

Ethyl-paraben removal in different aqueous matrices by the photo-Fenton process in optimal conditions [EP]0=5 mg dm-3, [H2O2]0 = 2.92·10−4 M and [Fe2+]0 = 1.85·10−5 M, T=25 ⍛C, Heraeus TNN 15/32 lamp, 15W, λ = 254 nm.

The removal rate of pollutants in different aqueous matrices by Fenton process -- or its derivatives -- has been investigated in recent years, and some controversies have arisen. For instance, Derbalah et al. [51] reported that the degradation of fenitrothion in river water by Fenton and photo-Fenton processes was slightly faster than in pure water and attributed this fact to the presence of Fe2+ and Fe3+ in natural water, which caused a higher rate of .OH radicals generation. Similarly, Moncayo-Lasso et al. [52] attribute the faster mineralization of dihydroxy-benzene by a photo-Fenton process in river-water compared to ultrapure water to the concurrence of three facts, namely i) the formation of photoactive intermediaries that contribute to mineralization by photoassisted electron transfers; ii) the presence of Fe3+ ions in river waters, that results in the generation of singlet oxygen, H2O2 and ·OH radicals that attack the dihydroxy-benzene compounds, and iii) the presence of humic acids that, at adequate pH (3-5) can form complexes with the Fe3+, increasing the amount of photoactive Fe3+ and therefore the efficiency of the process. Also, Jacobs et al. [53] reported that the presence of fulvic acids in river waters accelerates the degradation rate of caffeine approximately threefold.

However, more recently, Veloutsou et al. [54] reported a delay in the mineralization rate of atenolol and metoprolol in river waters by the photo-Fenton process with respect to an ultrapure aqueous matrix. An increase in the total consumption of H2O2 was reported, too. These authors indicate that hydroxyl radicals and other oxidizing species are neutralized by attacking other organic molecules naturally present in river waters. Also, ·OH radicals may be involved in reactions with inorganic ions such as chloride, nitrate, sulphate or phosphate. Nevertheless, the total disappearance of the initial compounds was also achieved after 10 min of illumination in river water as it is the case in the present study.

Likewise, Benitez et al. [55] reported a higher removal rate in ultrapure water when compared to other surface-water matrices. These authors asserted that the dissolved organic matter that naturally occurs in real water matrices may deplete at least part of the oxidizing species and, hence, the total amount of oxidizing agents available for the degradation of the target pollutants decreases. Obviously, in the case of ultrapure water, the emitted radiation and the oxidizing agents generated in situ are almost totally devoted to the degradation of the pollutants, which results in higher removal rates. The detrimental effect of the presence of non-dissolved organic matter in the aqueous media has also been reported by Polo-Lopez et al. [56] when investigating the removal of phytopathogen fungi spores in natural effluents.

On the other hand, Neamtu et al. [57] indicated that the presence of inorganic anions dissolved in the real water matrices could exert a coordination effect over the Fe2+ and, mostly, Fe3+ ions that are involved in the photo-Fenton process. For instance, the presence of chloride ion in real waters favours the formation of thermodynamically stable Fe3+ complexes as, for instance, FeCl2+ or FeCl2+. Furthermore, sulphate ions may also form complexes such as Fe[(SO4)]2+. Consequently, the regeneration of Fe2+ ions is handicapped and the process efficiency decreases markedly. In addition, Fe2+ and Fe3+ ions may also form stable complexes with certain organic compounds that naturally occur in real waters, which also contribute to lower the amount of oxidizing species available to react with the pollutant. The same conclusion was reached by De Luna et al. [58] when investigating the degradation of dimethyl sulfoxide by different Fenton processes.

Finally, but not less important, it must be taken into consideration that the presence of organic matter in real water matrices may hinder the penetration of light due to increased turbidity. Table 4 summarizes the operational conditions that lead to optimum removal of different pollutants using the photo-Fenton process. It is worth noting that the experimental conditions that resulted in an optimized removal of the target molecules are, as a rule, similar to those reported in this work (i.e., [H2O2]0 to [Fe2+]0 ratio equal to 15.8 and pH = 3.5).

Table 4

Optimal conditions reported for the removal of different pollutants by photo-Fenton processes.

Target pollutantInitial ConcentrationOptimal [H2O2]0 /[Fe2+]0Optimal pHRemoval efficiency (%)pH rangeT(⍛C)Reference
λ-cyhalothrin10 ppm12.83n.a.1002.5n.a.[59]
6 common pharmaceuticals5 ppm each155503-730-35[60]
Carmoisine20 ppm203.5952-625[37]
Sucralose15 ppm173962-738[49]
Azure-B30 ppm13.22.21001.5-2.725[61]

4 Conclusions

Removal rates of parabens (methyl-paraben (MP), ethyl-paraben (EP), propyl-paraben (PP), and butyl-paraben (BP)) in ultrapure water using different photocatalyzed processes (photo-Fenton, Fenton, UV-H2O2, UV-TiO2 and UV-TiO2-H2O2) have been studied.

  1. The photo-Fenton process is the most efficient photocatalyzed technology to remove these contaminants.

  2. With regard to the influence of experimental conditions on the photo-Fenton system, [H2O2]0 is the variable that most strongly influences the removal of parabens, followed by [Fe2+]0. After 30 minutes, the removal of these pollutants reached 100%.

  3. Total removal of parabens is achieved using initial concentrations of H2O2 and Fe2+ equal to 2.92·10-4 and 1.85·10-4 mol dm-3, respectively.

  4. Experimental confirmation of these results in other surface aqueous matrices (river water, reservoir water and WWTP effluent) was carried out. The removal efficiency of photo-Fenton process in ultrapure water and river water reaches 100%, decreasing to approximately 80% for WWTP effluent and reservoir water. In all cases, the removal rate of parabens was slower when natural waters were used.

Acknowledgements

The authors gratefully acknowledge national financial support via the CICYT-CTM 2016-75873-R project, as well as through Gobierno de Extremadura GR15067 and IB16016 projects.

  1. Conflict of interest

    Conflicts of interest: There are no conflicts to declare.

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Received: 2018-11-28
Accepted: 2019-09-29
Published Online: 2019-12-31

© 2019 Joaquin R. Dominguez et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 Public License.

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  118. Liquid−Liquid Extraction of Linalool from Methyl Eugenol with 1-Ethyl-3-methylimidazolium Hydrogen Sulfate [EMIM][HSO4] Ionic Liquid
  119. Synthesis of Graphene Oxide Through Ultrasonic Assisted Electrochemical Exfoliation
  120. Special Issue on ISCMP 2018
  121. Synthesis and antiproliferative evaluation of some 1,4-naphthoquinone derivatives against human cervical cancer cells
  122. The influence of the grafted aryl groups on the solvation properties of the graphyne and graphdiyne - a MD study
  123. Electrochemical modification of platinum and glassy carbon surfaces with pyridine layers and their use as complexing agents for copper (II) ions
  124. Effect of Electrospinning Process on Total Antioxidant Activity of Electrospun Nanofibers Containing Grape Seed Extract
  125. Effect Of Thermal Treatment Of Trepel At Temperature Range 800-1200˚C
  126. Topical Issue on Agriculture
  127. The effect of Cladophora glomerata exudates on the amino acid composition of Cladophora fracta and Rhizoclonium sp.
  128. Influence of the Static Magnetic Field and Algal Extract on the Germination of Soybean Seeds
  129. The use of UV-induced fluorescence for the assessment of homogeneity of granular mixtures
  130. The use of microorganisms as bio-fertilizers in the cultivation of white lupine
  131. Lyophilized apples on flax oil and ethyl esters of flax oil - stability and antioxidant evaluation
  132. Production of phosphorus biofertilizer based on the renewable materials in large laboratory scale
  133. Human health risk assessment of potential toxic elements in paddy soil and rice (Oryza sativa) from Ugbawka fields, Enugu, Nigeria
  134. Recovery of phosphates(V) from wastewaters of different chemical composition
  135. Special Issue on the 4th Green Chemistry 2018
  136. Dead zone for hydrogenation of propylene reaction carried out on commercial catalyst pellets
  137. Improved thermally stable oligoetherols from 6-aminouracil, ethylene carbonate and boric acid
  138. The role of a chemical loop in removal of hazardous contaminants from coke oven wastewater during its treatment
  139. Combating paraben pollution in surface waters with a variety of photocatalyzed systems: Looking for the most efficient technology
  140. Special Issue on Chemistry Today for Tomorrow 2019
  141. Applying Discriminant and Cluster Analyses to Separate Allergenic from Non-allergenic Proteins
  142. Chemometric Expertise Of Clinical Monitoring Data Of Prolactinoma Patients
  143. Chemomertic Risk Assessment of Soil Pollution
  144. New composite sorbent for speciation analysis of soluble chromium in textiles
  145. Photocatalytic activity of NiFe2O4 and Zn0.5Ni0.5Fe2O4 modified by Eu(III) and Tb(III) for decomposition of Malachite Green
  146. Photophysical and antibacterial activity of light-activated quaternary eosin Y
  147. Spectral properties and biological activity of La(III) and Nd(III) Monensinates
  148. Special Issue on Monitoring, Risk Assessment and Sustainable Management for the Exposure to Environmental Toxins
  149. Soil organic carbon mineralization in relation to microbial dynamics in subtropical red soils dominated by differently sized aggregates
  150. A potential reusable fluorescent aptasensor based on magnetic nanoparticles for ochratoxin A analysis
  151. Special Issue on 13th JCC 2018
  152. Fluorescence study of 5-nitroisatin Schiff base immobilized on SBA-15 for sensing Fe3+
  153. Thermal and Morphology Properties of Cellulose Nanofiber from TEMPO-oxidized Lower part of Empty Fruit Bunches (LEFB)
  154. Encapsulation of Vitamin C in Sesame Liposomes: Computational and Experimental Studies
  155. A comparative study of the utilization of synthetic foaming agent and aluminum powder as pore-forming agents in lightweight geopolymer synthesis
  156. Synthesis of high surface area mesoporous silica SBA-15 by adjusting hydrothermal treatment time and the amount of polyvinyl alcohol
  157. Review of large-pore mesostructured cellular foam (MCF) silica and its applications
  158. Ion Exchange of Benzoate in Ni-Al-Benzoate Layered Double Hydroxide by Amoxicillin
  159. Synthesis And Characterization Of CoMo/Mordenite Catalyst For Hydrotreatment Of Lignin Compound Models
  160. Production of Biodiesel from Nyamplung (Calophyllum inophyllum L.) using Microwave with CaO Catalyst from Eggshell Waste: Optimization of Transesterification Process Parameters
  161. The Study of the Optical Properties of C60 Fullerene in Different Organic Solvents
  162. Composite Material Consisting of HKUST-1 and Indonesian Activated Natural Zeolite and its Application in CO2 Capture
  163. Topical Issue on Environmental Chemistry
  164. Ionic liquids modified cobalt/ZSM-5 as a highly efficient catalyst for enhancing the selectivity towards KA oil in the aerobic oxidation of cyclohexane
  165. Application of Thermal Resistant Gemini Surfactants in Highly Thixotropic Water-in-oil Drilling Fluid System
  166. Screening Study on Rheological Behavior and Phase Transition Point of Polymer-containing Fluids produced under the Oil Freezing Point Temperature
  167. The Chemical Softening Effect and Mechanism of Low Rank Coal Soaked in Alkaline Solution
  168. The Influence Of NO/O2 On The NOx Storage Properties Over A Pt-Ba-Ce/γ-Al2O3 Catalyst
  169. Special Issue on the International conference CosCI 2018
  170. Design of SiO2/TiO2 that Synergistically Increases The Hydrophobicity of Methyltrimethoxysilane Coated Glass
  171. Antidiabetes and Antioxidant agents from Clausena excavata root as medicinal plant of Myanmar
  172. Development of a Gold Immunochromatographic Assay Method Using Candida Biofilm Antigen as a Bioreceptor for Candidiasis in Rats
  173. Special Issue on Applied Biochemistry and Biotechnology 2019
  174. Adsorption of copper ions on Magnolia officinalis residues after solid-phase fermentation with Phanerochaete chrysosporium
  175. Erratum
  176. Erratum to: Sand Dune Characterization For Preparing Metallurgical Grade Silicon
https://doi.org/10.1515/chem-2019-0133
Schlagwörter für diesen Artikel
Water Treatment; Surface-waters; Parabens pollution; photo-assisted Fenton; Remediation Systems
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Artikel in diesem Heft

  1. Regular Articles
  2. Research on correlation of compositions with oestrogenic activity of Cistanche based on LC/Q-TOF-MS/MS technology
  3. Efficacy of Pyrus elaeagnifolia subsp. elaeagnifolia in acetic acid–induced colitis model
  4. Anti-inflammatory and antinociceptive features of Bryonia alba L.: As a possible alternative in treating rheumatism
  5. High efficiency liposome fusion induced by reducing undesired membrane peptides interaction
  6. Prediction of the Blood-Brain Barrier Permeability Using RP-18 Thin Layer Chromatography
  7. Phytic Acid Extracted from Rice Bran as a Growth Promoter for Euglena gracilis
  8. Development of a validated spectrofluorimetric method for assay of sotalol hydrochloride in tablets and human plasma: application for stability-indicating studies
  9. Topological Indices of Hyaluronic Acid-Paclitaxel Conjugates’ Molecular Structure in Cancer Treatment
  10. Thermodynamic properties of the bubble growth process in a pool boiling of water-ethanol mixture two-component system
  11. Critical Roles of the PI3K-Akt-mTOR Signaling Pathway in Apoptosis and Autophagy of Astrocytes Induced by Methamphetamine
  12. Characteristics of Stable Hydrogen and Oxygen Isotopes of Soil Moisture under Different Land Use in Dry Hot Valley of Yuanmou
  13. Specific, highly sensitive and simple spectrofluorimetric method for quantification of daclatasvir in HCV human plasma patients and in tablets dosage form
  14. Chromium-modified cobalt molybdenum nitrides as catalysts for ammonia synthesis
  15. Langerhans cell-like dendritic cells treated with ginsenoside Rh2 regulate the differentiation of Th1 and Th2 cells in vivo
  16. Identification of Powdery Mildew Blumeria graminis f. sp. tritici Resistance Genes in Selected Wheat Varieties and Development of Multiplex PCR
  17. Computational Analysis of new Degree-based descriptors of oxide networks
  18. The Use Of Chemical Composition And Additives To Classify Petrol And Diesel Using Gas Chromatography–Mass Spectrometry And Chemometric Analysis: A Uk Study
  19. Minimal Energy Tree with 4 Branched Vertices
  20. Jatropha seed oil derived poly(esteramide-urethane)/ fumed silica nanocomposite coatings for corrosion protection
  21. Calculating topological indices of certain OTIS interconnection networks
  22. Energy storage analysis of R125 in UIO-66 and MOF-5 nanoparticles: A molecular simulation study
  23. Velvet Antler compounds targeting major cell signaling pathways in osteosarcoma - a new insight into mediating the process of invasion and metastasis in OS
  24. Effects of Azadirachta Indica Leaf Extract, Capping Agents, on the Synthesis of Pure And Cu Doped ZnO-Nanoparticles: A Green Approach and Microbial Activity
  25. Aqueous Micro-hydration of Na+(H2O)n=1-7 Clusters: DFT Study
  26. A proposed image-based detection of methamidophos pesticide using peroxyoxalate chemiluminescence system
  27. Phytochemical screening and estrogenic activity of total glycosides of Cistanche deserticola
  28. Biological evaluation of a series of benzothiazole derivatives as mosquitocidal agents
  29. Chemical pretreatments of Trapa bispinosa's peel (TBP) biosorbent to enhance adsorption capacity for Pb(ll)
  30. Dynamic Changes in MMP1 and TIMP1 in the Antifibrotic Process of Dahuang Zhechong Pill in Rats with Liver Fibrosis
  31. The Optimization and Production of Ginkgolide B Lipid Microemulsion
  32. Photodynamic Therapy Enhanced the Antitumor Effects of Berberine on HeLa Cells
  33. Chiral and Achiral Enantiomeric Separation of (±)-Alprenolol
  34. Correlation of Water Fluoride with Body Fluids, Dental Fluorosis and FT4, FT3 –TSH Disruption among Children in an Endemic Fluorosis area in Pakistan
  35. A one-step incubation ELISA kit for rapid determination of dibutyl phthalate in water, beverage and liquor
  36. Free Radical Scavenging Activity of Essential Oil of Eugenia caryophylata from Amboina Island and Derivatives of Eugenol
  37. Effects of Blue and Red Light On Growth And Nitrate Metabolism In Pakchoi
  38. miRNA-199a-5p functions as a tumor suppressor in prolactinomas
  39. Solar photodegradation of carbamazepine from aqueous solutions using a compound parabolic concentrator equipped with a sun tracking system
  40. Influence of sub-inhibitory concentration of selected plant essential oils on the physical and biochemical properties of Pseudomonas orientalis
  41. Preparation and spectroscopic studies of Fe(II), Ru(II), Pd(II) and Zn(II) complexes of Schiff base containing terephthalaldehyde and their transfer hydrogenation and Suzuki-Miyaura coupling reaction
  42. Complex formation in a liquid-liquid extraction-chromogenic system for vanadium(IV)
  43. Synthesis, characterization (IR, 1H, 13C & 31P NMR), fungicidal, herbicidal and molecular docking evaluation of steroid phosphorus compounds
  44. Analysis and Biological Evaluation of Arisaema Amuremse Maxim Essential Oil
  45. A preliminary assessment of potential ecological risk and soil contamination by heavy metals around a cement factory, western Saudi Arabia
  46. Anti- inflammatory effect of Prunus tomentosa Thunb total flavones in LPS-induced RAW264.7 cells
  47. Collaborative Influence of Elevated CO2 Concentration and High Temperature on Potato Biomass Accumulation and Characteristics
  48. Methods of extraction, physicochemical properties of alginates and their applications in biomedical field – a review
  49. Characteristics of liposomes derived from egg yolk
  50. Preparation of ternary ZnO/Ag/cellulose and its enhanced photocatalytic degradation property on phenol and benzene in VOCs
  51. Influence of Human Serum Albumin Glycation on the Binding Affinities for Natural Flavonoids
  52. Synthesis and antioxidant activity of 2-methylthio-pyrido[3,2-e][1,2,4] triazolo[1,5-a]pyrimidines
  53. Comparative study on the antioxidant activities of ten common flower teas from China
  54. Molecular Properties of Symmetrical Networks Using Topological Polynomials
  55. Synthesis of Co3O4 Nano Aggregates by Co-precipitation Method and its Catalytic and Fuel Additive Applications
  56. Phytochemical analysis, Antioxidant and Antiprotoscolices potential of ethanol extracts of selected plants species against Echinococcus granulosus: In-vitro study
  57. Silver nanoparticles enhanced fluorescence for sensitive determination of fluoroquinolones in water solutions
  58. Simultaneous Quantification of the New Psychoactive Substances 3-FMC, 3-FPM, 4-CEC, and 4-BMC in Human Blood using GC-MS
  59. Biodiesel Production by Lipids From Indonesian strain of Microalgae Chlorella vulgaris
  60. Miscibility studies of polystyrene/polyvinyl chloride blend in presence of organoclay
  61. Antibacterial Activities of Transition Metal complexes of Mesocyclic Amidine 1,4-diazacycloheptane (DACH)
  62. Novel 1,8-Naphthyridine Derivatives: Design, Synthesis and in vitro screening of their cytotoxic activity against MCF7 cell line
  63. Investigation of Stress Corrosion Cracking Behaviour of Mg-Al-Zn Alloys in Different pH Environments by SSRT Method
  64. Various Combinations of Flame Retardants for Poly (vinyl chloride)
  65. Phenolic compounds and biological activities of rye (Secale cereale L.) grains
  66. Oxidative degradation of gentamicin present in water by an electro-Fenton process and biodegradability improvement
  67. Optimizing Suitable Conditions for the Removal of Ammonium Nitrogen by a Microbe Isolated from Chicken Manure
  68. Anti-inflammatory, antipyretic, analgesic, and antioxidant activities of Haloxylon salicornicum aqueous fraction
  69. The anti-corrosion behaviour of Satureja montana L. extract on iron in NaCl solution
  70. Interleukin-4, hemopexin, and lipoprotein-associated phospholipase A2 are significantly increased in patients with unstable carotid plaque
  71. A comparative study of the crystal structures of 2-(4-(2-(4-(3-chlorophenyl)pipera -zinyl)ethyl) benzyl)isoindoline-1,3-dione by synchrotron radiation X-ray powder diffraction and single-crystal X-ray diffraction
  72. Conceptual DFT as a Novel Chemoinformatics Tool for Studying the Chemical Reactivity Properties of the Amatoxin Family of Fungal Peptides
  73. Occurrence of Aflatoxin M1 in Milk-based Mithae samples from Pakistan
  74. Kinetics of Iron Removal From Ti-Extraction Blast Furnace Slag by Chlorination Calcination
  75. Increasing the activity of DNAzyme based on the telomeric sequence: 2’-OMe-RNA and LNA modifications
  76. Exploring the optoelectronic properties of a chromene-appended pyrimidone derivative for photovoltaic applications
  77. Effect of He Qi San on DNA Methylation in Type 2 Diabetes Mellitus Patients with Phlegm-blood Stasis Syndrome
  78. Cyclodextrin potentiometric sensors based on selective recognition sites for procainamide: Comparative and theoretical study
  79. Greener synthesis of dimethyl carbonate from carbon dioxide and methanol using a tunable ionic liquid catalyst
  80. Nonisothermal Cold Crystallization Kinetics of Poly(lactic acid)/Bacterial Poly(hydroxyoctanoate) (PHO)/Talc
  81. Enhanced adsorption of sulfonamide antibiotics in water by modified biochar derived from bagasse
  82. Study on the Mechanism of Shugan Xiaozhi Fang on Cells with Non-alcoholic Fatty Liver Disease
  83. Comparative Effects of Salt and Alkali Stress on Antioxidant System in Cotton (Gossypium Hirsutum L.) Leaves
  84. Optimization of chromatographic systems for analysis of selected psychotropic drugs and their metabolites in serum and saliva by HPLC in order to monitor therapeutic drugs
  85. Electrocatalytic Properties of Ni-Doped BaFe12O19 for Oxygen Evolution in Alkaline Solution
  86. Study on the removal of high contents of ammonium from piggery wastewater by clinoptilolite and the corresponding mechanisms
  87. Phytochemistry and toxicological assessment of Bryonia dioica roots used in north-African alternative medicine
  88. The essential oil composition of selected Hemerocallis cultivars and their biological activity
  89. Mechanical Properties of Carbon Fiber Reinforced Nanocrystalline Nickel Composite Electroforming Deposit
  90. Anti-c-myc efficacy block EGFL7 induced prolactinoma tumorigenesis
  91. Topical Issue on Applications of Mathematics in Chemistry
  92. Zagreb Connection Number Index of Nanotubes and Regular Hexagonal Lattice
  93. The Sanskruti index of trees and unicyclic graphs
  94. Valency-based molecular descriptors of Bakelite network BNmn
  95. Computing Topological Indices for Para-Line Graphs of Anthracene
  96. Zagreb Polynomials and redefined Zagreb indices of Dendrimers and Polyomino Chains
  97. Topological Descriptor of 2-Dimensional Silicon Carbons and Their Applications
  98. Topological invariants for the line graphs of some classes of graphs
  99. Words for maximal Subgroups of Fi24‘
  100. Generators of Maximal Subgroups of Harada-Norton and some Linear Groups
  101. Special Issue on POKOCHA 2018
  102. Influence of Production Parameters on the Content of Polyphenolic Compounds in Extruded Porridge Enriched with Chokeberry Fruit (Aronia melanocarpa (Michx.) Elliott)
  103. Effects of Supercritical Carbon Dioxide Extraction (SC-CO2) on the content of tiliroside in the extracts from Tilia L. flowers
  104. Impact of xanthan gum addition on phenolic acids composition and selected properties of new gluten-free maize-field bean pasta
  105. Impact of storage temperature and time on Moldavian dragonhead oil – spectroscopic and chemometric analysis
  106. The effect of selected substances on the stability of standard solutions in voltammetric analysis of ascorbic acid in fruit juices
  107. Determination of the content of Pb, Cd, Cu, Zn in dairy products from various regions of Poland
  108. Special Issue on IC3PE 2018 Conference
  109. The Photocatalytic Activity of Zns-TiO2 on a Carbon Fiber Prepared by Chemical Bath Deposition
  110. N-octyl chitosan derivatives as amphiphilic carrier agents for herbicide formulations
  111. Kinetics and Mechanistic Study of Hydrolysis of Adenosine Monophosphate Disodium Salt (AMPNa2) in Acidic and Alkaline Media
  112. Antimalarial Activity of Andrographis Paniculata Ness‘s N-hexane Extract and Its Major Compounds
  113. Special Issue on ABB2018 Conference
  114. Special Issue on ICCESEN 2017
  115. Theoretical Diagnostics of Second and Third-order Hyperpolarizabilities of Several Acid Derivatives
  116. Determination of Gamma Rays Efficiency Against Rhizoctonia solani in Potatoes
  117. Studies On Compatibilization Of Recycled Polyethylene/Thermoplastic Starch Blends By Using Different Compatibilizer
  118. Liquid−Liquid Extraction of Linalool from Methyl Eugenol with 1-Ethyl-3-methylimidazolium Hydrogen Sulfate [EMIM][HSO4] Ionic Liquid
  119. Synthesis of Graphene Oxide Through Ultrasonic Assisted Electrochemical Exfoliation
  120. Special Issue on ISCMP 2018
  121. Synthesis and antiproliferative evaluation of some 1,4-naphthoquinone derivatives against human cervical cancer cells
  122. The influence of the grafted aryl groups on the solvation properties of the graphyne and graphdiyne - a MD study
  123. Electrochemical modification of platinum and glassy carbon surfaces with pyridine layers and their use as complexing agents for copper (II) ions
  124. Effect of Electrospinning Process on Total Antioxidant Activity of Electrospun Nanofibers Containing Grape Seed Extract
  125. Effect Of Thermal Treatment Of Trepel At Temperature Range 800-1200˚C
  126. Topical Issue on Agriculture
  127. The effect of Cladophora glomerata exudates on the amino acid composition of Cladophora fracta and Rhizoclonium sp.
  128. Influence of the Static Magnetic Field and Algal Extract on the Germination of Soybean Seeds
  129. The use of UV-induced fluorescence for the assessment of homogeneity of granular mixtures
  130. The use of microorganisms as bio-fertilizers in the cultivation of white lupine
  131. Lyophilized apples on flax oil and ethyl esters of flax oil - stability and antioxidant evaluation
  132. Production of phosphorus biofertilizer based on the renewable materials in large laboratory scale
  133. Human health risk assessment of potential toxic elements in paddy soil and rice (Oryza sativa) from Ugbawka fields, Enugu, Nigeria
  134. Recovery of phosphates(V) from wastewaters of different chemical composition
  135. Special Issue on the 4th Green Chemistry 2018
  136. Dead zone for hydrogenation of propylene reaction carried out on commercial catalyst pellets
  137. Improved thermally stable oligoetherols from 6-aminouracil, ethylene carbonate and boric acid
  138. The role of a chemical loop in removal of hazardous contaminants from coke oven wastewater during its treatment
  139. Combating paraben pollution in surface waters with a variety of photocatalyzed systems: Looking for the most efficient technology
  140. Special Issue on Chemistry Today for Tomorrow 2019
  141. Applying Discriminant and Cluster Analyses to Separate Allergenic from Non-allergenic Proteins
  142. Chemometric Expertise Of Clinical Monitoring Data Of Prolactinoma Patients
  143. Chemomertic Risk Assessment of Soil Pollution
  144. New composite sorbent for speciation analysis of soluble chromium in textiles
  145. Photocatalytic activity of NiFe2O4 and Zn0.5Ni0.5Fe2O4 modified by Eu(III) and Tb(III) for decomposition of Malachite Green
  146. Photophysical and antibacterial activity of light-activated quaternary eosin Y
  147. Spectral properties and biological activity of La(III) and Nd(III) Monensinates
  148. Special Issue on Monitoring, Risk Assessment and Sustainable Management for the Exposure to Environmental Toxins
  149. Soil organic carbon mineralization in relation to microbial dynamics in subtropical red soils dominated by differently sized aggregates
  150. A potential reusable fluorescent aptasensor based on magnetic nanoparticles for ochratoxin A analysis
  151. Special Issue on 13th JCC 2018
  152. Fluorescence study of 5-nitroisatin Schiff base immobilized on SBA-15 for sensing Fe3+
  153. Thermal and Morphology Properties of Cellulose Nanofiber from TEMPO-oxidized Lower part of Empty Fruit Bunches (LEFB)
  154. Encapsulation of Vitamin C in Sesame Liposomes: Computational and Experimental Studies
  155. A comparative study of the utilization of synthetic foaming agent and aluminum powder as pore-forming agents in lightweight geopolymer synthesis
  156. Synthesis of high surface area mesoporous silica SBA-15 by adjusting hydrothermal treatment time and the amount of polyvinyl alcohol
  157. Review of large-pore mesostructured cellular foam (MCF) silica and its applications
  158. Ion Exchange of Benzoate in Ni-Al-Benzoate Layered Double Hydroxide by Amoxicillin
  159. Synthesis And Characterization Of CoMo/Mordenite Catalyst For Hydrotreatment Of Lignin Compound Models
  160. Production of Biodiesel from Nyamplung (Calophyllum inophyllum L.) using Microwave with CaO Catalyst from Eggshell Waste: Optimization of Transesterification Process Parameters
  161. The Study of the Optical Properties of C60 Fullerene in Different Organic Solvents
  162. Composite Material Consisting of HKUST-1 and Indonesian Activated Natural Zeolite and its Application in CO2 Capture
  163. Topical Issue on Environmental Chemistry
  164. Ionic liquids modified cobalt/ZSM-5 as a highly efficient catalyst for enhancing the selectivity towards KA oil in the aerobic oxidation of cyclohexane
  165. Application of Thermal Resistant Gemini Surfactants in Highly Thixotropic Water-in-oil Drilling Fluid System
  166. Screening Study on Rheological Behavior and Phase Transition Point of Polymer-containing Fluids produced under the Oil Freezing Point Temperature
  167. The Chemical Softening Effect and Mechanism of Low Rank Coal Soaked in Alkaline Solution
  168. The Influence Of NO/O2 On The NOx Storage Properties Over A Pt-Ba-Ce/γ-Al2O3 Catalyst
  169. Special Issue on the International conference CosCI 2018
  170. Design of SiO2/TiO2 that Synergistically Increases The Hydrophobicity of Methyltrimethoxysilane Coated Glass
  171. Antidiabetes and Antioxidant agents from Clausena excavata root as medicinal plant of Myanmar
  172. Development of a Gold Immunochromatographic Assay Method Using Candida Biofilm Antigen as a Bioreceptor for Candidiasis in Rats
  173. Special Issue on Applied Biochemistry and Biotechnology 2019
  174. Adsorption of copper ions on Magnolia officinalis residues after solid-phase fermentation with Phanerochaete chrysosporium
  175. Erratum
  176. Erratum to: Sand Dune Characterization For Preparing Metallurgical Grade Silicon
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