Volume 238, Issue 12

The present study is about the effect of gamma radiations on the degradation of Acid Violet 49 (AV49) in the presence of H 2 O 2 (γ/H 2 O 2 ). The Cs-137 radiation source was calibrated to irradiate the aqueous solution of AV49 within the 1 kGy, 5 kGy & 10 kGy dose range. The results showed that 50–150 mg/L of AV49 was effectively degraded by γ radiation (85 %), however, the concentration of H 2 O 2 in the range of 0.2–0.6 mL promoted degradation to 90 % and 98 %, respectively. It was observed that all absorption bands declined with rising irradiation dose and disappeared completely after 10 kGy applied dose. pH conditions (3, 5,7, and 9) were used in the radio-lytic degradation of AV49, the results showed that the best degradation efficiency has been found for pH 9. The optimum degradation rate is higher (98 %) with a 50 mg/L concentration of AV49, 0.6 mL H 2 O 2, and pH 9 at a 10 kGy absorbed dose. In addition, the influence of various parameters on the rate of degradation such as the effect of irradiation dose, pH, H 2 O 2 , and dye (AV49) concentration was also studied. Furthermore, the removal of total organic carbon TOC was not as effective as that of the AV 49. Total nitrogen TN was not completely removed even at high dosage. Radio-lytic degradation of AV49 was analyzed by using Fourier transform infrared spectroscopy (FTIR) and liquid chromatography coupled to mass spectrometry (LC-MS) as an analytical technique. Results revealed that the proposed methodology for degradation of dyes is effective and probably could be applied for the removal of other toxic pollutants.

Herein, we fabricated a highly efficient oxygen-doped graphitic carbon nitride (O–CN) and layered double hydroxide (LDH) nanocomposite photocatalyst and utilized it in the degradation of organic dyes in wastewater. The composite’s structure, morphology, and different optical features were examined using different techniques such as FT-IR spectroscopy, UV-visible spectroscopy, scanning electron microscopy (SEM), SEM-EDX, energy dispersive X-ray (EDX), and X-ray diffraction (XRD). The composite has shown a crystalline structure, in contrast to the amorphous nature of oxygen-doped g-C 3 N 4 . Using a wide range of experimental parameters, including dye concentration, visible light, irradiation time, catalyst dose, contact time, and pH, the increase in the reaction performance of the catalyst was observed. The results reveal that 98.5 % adsorption degradation efficiency increased with the increase in catalyst dosage, contact time, and pH. The as-fabricated photocatalyst generated reactive species that were involved in the degradation of methylene blue (MB) dye upon exposure to visible light irradiation.

This study could present the size and morphology of two synthesized nanoparticles (NPs) by observing their smallest possible dimensions. Lanthanum carbonate nanoparticles were synthesized by sonochemical method through the interaction of lanthanum acetate hydrate and sodium carbonate in an aqueous medium with a probe sonicator. After rigorous washing followed by drying, the La 2 (CO 3 ) 3 ·8H 2 O(S1) NPs were calcined at a temperature of 600 °C to obtain lanthanum oxide nanoparticles (S2). Both NPs were characterised through various instrumental techniques. PXRD study showed orthorhombic with space group of Pccn (56) and hexagonal phases with space group of P 3 ‾ m 1 $P\overline{3}m1$ (164) for S1 and S2 respectively whose morphology and elemental analysis were studied through FESEM and EDX. High resolution TEM image of La 2 (CO 3 ) 3 ·8H 2 O and La 2 O 3 showed spherical shapes of the nanoparticles. Further study of XPS and FTIR conveyed detailed information of both nanoparticles whose TGA-DSC showed three step decomposition curves. The size and morphology of the synthesized nanoparticles have been found to have a distinct morphology and are found comparatively smaller in size than those observed in the earlier reported works (Table 1 Table 1: Comparative study of synthesized lanthanum carbonate and lanthanum oxide NPs with various techniques applied by other researchers. Sl. no. Name of NPs Methods Conditions Size of NP Reference 1 La 2 (CO 3 ) 3 ·8H 2 O Sonochemical method Time: 25 min XRD: Pccn (56) a  = 8.9840 Å b  = 9.5800 Å c  = 17.0000 Å This work Temperature: 301 K Size : 24.102 nm Starting materials: (a) La(CH 3 COO) 2 : 0.050 M (b) Na 2 CO 3 :0.050 M TEM : Size : 4–30 nm La 2 (CO 3 ) 3 Reverse micelles Time: 1 h XRD : Size : nanoparticles absent [20] Temperature: 303 K Starting materials: (a) Triton X-100 (b) Cyclohexane (c) n-butylalcohol (d) La(NO 3 ) 3(aq) e) NaCO 3(aq) La 2 (CO 3 ) 3 ·8H 2 O Hydrothermal Time: 2–5 days XRD : Pccn a  = 8.984 Å b  = 9.580 Å c  = 17.00 Å [21] Temperature: 773 K Size : nanoparticles absent Prepared by slow hydrolysis of La(CCl 3 COO) 3 La 2 (CO 3 ) 3 ·1.4H 2 O Hydrothermal Time: 1 h 30 min Structure unknown [22] Temperature: 368 K Starting material: (a) La 2 O 3 (b) HNO 3 (c) Urea La 2 (CO 3 ) 3 ·1.7H 2 O Sonochemical Time: 30 min XRD: a  = 8.990 Å c  = 9.675 Å [23] Temperature: not specified Size : not specified (a) La(OAC) 3 (b) Na 2 CO 3 TEM : Size: 25–35 nm Concentration: (a) La(OAC) 3 : 0.051 M (b) Na 2 CO 3 : 0.251 M La 2 (CO 3 ) 3 ·5H 2 O Hydrothermal Time: XRD: Pbca a  = 9.0167 Å b  = 12.842 Å c  = 9.6331 Å [24] Temperature: Size : not specified Starting materials: (a) La 2 O 3 (b) HCl (c) Na 2 CO 3 La 2 (CO 3 ) 3 ·3.4H 2 O Hydrothermal Time: 3–4 h XRD: P 2 1 2 1 2 a  = 9.57 Å b  = 12.65 Å c  = 8.94 Å [25] Temperature: 298–308 K Size : not specified Starting materials: (a) LaCl 3 (b) NH 4 HCO 3 2 La 2 O 3 Thermal decomposition Time: 2 h P 3 m 1 a  = 3.973 Å b  = 3.9373 Å c  = 6.129 Å [26] Temperature: 1073 K Size : 15 nm Starting material: La(OH) 3 nanorods TEM : Size : 23 nm La 2 O 3 Thermal decomposition Time: 2 h XRD : a  = 11.347 Å [23] Temperature: 873 K Size: 30 nm Starting material: La 2 (CO 3 ) 3 ·1.7H 2 O TEM : Size : 30 nm La 2 O 3 Thermal decomposition Time: not specified Not specified [27] Temperature: 1198 K Starting material: (a) La(NO 3 ) 3 ·9H 2 O (b) NH 4 HCO 3 La 2 O 3 Thermal decomposition Time: 4 h Not specified [28] Temperature: 1073 K Starting material: La(OH) 3 La 2 O 3 Thermal decomposition Time: 2 h P 3 ‾ m 1 $P\overline{3}m1$ a  = 3.973 Å b  = 3.9373 Å c  = 6.129 Å This work Temperature: 873 K XRD : Size : 43.26 nm Starting material: La 2 (CO 3 ) 3 ·8H 2 O TEM: Size : 17–34 nm ).

This paper addresses the combined effects of varying C/H and C/O ratios as well as of the molecular structure of the fuels selected on the normalized soot volume fraction f V . For the simulations, an already existing and validated reaction mechanism for the pyrolysis of C 2 H 2 in argon, Aghsaee et al. ( Combust. Flame 2014, 161 , 2263–2269), was used in the current work. It was extended with PAH reactions from coronene (C 24 H 12 ) up to ovalene (C 32 H 14 ), whereas general principles for the rapid build-up of large PAHs were presented. Soot formation was modeled according to Appel et al. ( Combust. Flame 2000, 121 , 122–136) by applying the method of moments. A validation of the extended reaction model was carried out for shock-wave-induced O 2 /C 2 H 2 mixtures from literature. In the following, the influence of blends of methane (CH 4 ), formaldehyde (CH 2 O), methanol (CH 3 OH), and dimethyl ether (CH 3 ) 2 O on soot formation during C 2 H 2 pyrolysis diluted in Ar was studied. Special emphasis was laid on the inception chemistry of soot formation. The role of intermediates, such as the propargyl radical (C 3 H 3 ), leading towards benzene and polyaromatic hydrocarbon (PAH) formation and their interplay with hydrogen molecules (H 2 ) to H atoms (H) ratio was examined. All blends increased the ratio of the concentrations of H 2 and H leading thus to reduced soot inception and soot formation. However, soot suppressing effects were overrun by supporting ones when the additives provided suitable molecular groups, such as methyl radicals (CH 3 ), in sufficient high concentrations for early aromatic ring formation. Thus, a prominent synergistic effect on soot formation was found for the CH 4 /C 2 H 2 mixture only. Besides, species able to mirror characteristics of the soot formation process, such as the peak value of the normalized soot volume fraction, are presented. The findings of this work indicate the synergistic effect of H 2 /H and C/O ratios as well as of methyl radicals on the PAHs’ production of appropriate size able to initiate soot inception process in an aliphatic fuel.

The significance of greenhouse gases for climate change is assessed in the case of carbon dioxide on the basis of thermodynamic data. According to the values of the molar heat capacity, no increased heat-storing property of this greenhouse gas can be determined. The absorption and desorption of infrared radiation by the greenhouse gases is seen as a reversible dynamic process, which on the one hand reduces the IR radiation from the Sun, and on the other hand, delays the re-radiation from the Earth. As converters of heat into IR photons and vice versa, the greenhouse gases play an important role in balancing the radiation. The direction of heat transport in the atmosphere is determined by the 2nd Law of Thermodynamics. The range of IR radiation is determined according to the gradation of air pressure in the atmosphere.

Hybrid perovskite materials, known for their potential in cost-effective optoelectronic applications, face a knowledge gap in crucial areas, particularly the atomic-level properties of the surface. This study addresses this challenge by refining ab initio methods for characterizing surface structures of cubic methylammonium lead bromide and methylammonium tin bromide (MAMeBr 3 with Me = Sn, Pb), avoiding superficial restrictions in atomic movement during geometry optimization. The resulting structures confirmed nearly random MA + molecule alignment, comparable to real-world experimental conditions. Calculating surface energies for these structures with crystal orientations {100} and {110}, each with different terminations, provides valuable insights into structural properties. Using a carefully chosen thermodynamic reference state, mimicking experimental conditions enables a thermodynamic discussion and facilitates the modulation of the MeBr 2 component’s chemical potential. This modulation, in turn, allows for the prediction of crystal morphologies, as illustrated by Wulff’s construction. This approach establishes a crucial link between theoretical predictions and experimental conditions, shedding light on the complexities of hybrid perovskite materials.

The modern world is moving towards electric vehicles (EV) due to the increment in greenhouse gas (GHG) emissions, global warming, and the lack of fossil fuels. EVs can overcome these issues by using batteries instead of fuel. But increasing and maintaining the batteries is a major challenge in EVs because of the large heat emissions from the batteries. In order to overcome these issues and increase the performance of the batteries, a heat pipe (HP) is attached to the passive cooling system. This study aims to improve the performance of batteries and the thermal conductivity of HP with a combination of refrigerant and nanofluid (nanorefrigerant) as working fluids. Copper HP with R-134a or SWCNT is selected for this study. The thermal resistance and thermal conductivity of HP with R-134a and SWCNT were observed for several heat conditions. From the study, it was well observed that changing the working fluid inside the HP affects the thermal performance and the cooling capacity of batteries. Fixing an HP to a battery would decrease the battery’s temperature effectively. Furthermore, increasing the heat power in an evaporator section decreases the thermal resistance and enhances thermal conductivity with the shortest time limit because of Brownian motion.

Water contamination by toxic organic dyes represents a significant global challenge necessitating effective remediation strategies. Due to their high catalytic activity, considerable attention has been gained to metal-based nanocatalysts. Cellulose acetate sheets supported by gold nanoparticles through a reduction method were synthesized. The composite synthesized material presents a compelling platform for catalytic reduction in the remediation of toxic organic pollutants, ensuring controlled particle size and stability. In this study, the prepared cellulose acetate sheet (CA sheet ) was dipped in a 0.001 M aqueous chloroauric acid (HAuCl 4 ) solution and reduced by immersion in a 0.1 M sodium borohydride (NaBH 4 ) aqueous solution. After the successful preparation of virgin cellulose acetate sheet (CA sheet ) and gold-supported cellulose acetate sheet (Au-CA sheet ) samples were assessed by scanning electron microscopy (SEM), X-ray crystallography (XRD), energy dispersive X-rays spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) analysis. The catalytic reduction reaction of toxic compounds i.e. reduction of 4-nitroaniline (4-NA), Congo red (CR), and reactive yellow (RY-42) by using NaBH 4 . The catalytic activity of the Au-CA sheet was exhibited by the reaction rate constant ( k app ) values 0.3189, 0.1596, and 0.1593 min −1 for CR, 4-NA, and RY-42 respectively. This kind of procedure for Au-CA sheet synthesis may be valid for different applications in catalysis, sensing, and environmental application.