Oxidation Method Research Articles

Effect of purification methods on the quality and morphology of plastic waste-derived carbon nanotubes

Recent innovative research efforts on the usage of plastic wastes as a cheap carbon source for carbon nanotubes (CNTs) production have emerged as a low-cost and sustainable means of producing CNTs. However, plastic waste-derived CNTs are rarely used in some purity-sensitive and high-alignment needed applications due to the poor quality of CNTs resulting from the abundance of impurities such as non-crystalline amorphous carbon, metallic nanoparticles, and other impurities. Therefore, purification is a crucial issue to be addressed to fully harness all potential applications of CNTs derived from waste plastic materials. Here, the effect of employing different purification methods on the morphology and purity of waste plastic-derived CNTs was investigated. CNTs were synthesized using waste polypropylene plastic as carbon feedstock via a single-stage catalytic chemical vapour deposition (CVD) technique. As-produced CNTs were purified using liquid-phase oxidation (chemical oxidation in nitric acid), gas-phase oxidation in air, and a combination of both liquid- and gas-phase oxidation methods. The synthesized and purified CNTs were characterized for morphology, purity, surface functional groups, thermal stability, and crystallinity using Transmission electron microscopy (TEM), Raman spectroscopy, Fourier Transform Infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and X-ray diffraction (XRD), respectively. Results obtained showed that a combination of both liquid and gas phase oxidation purification techniques resulted in purer, better quality, and less defective CNTs with an IG’/IG value of 0.89 and ID/IG value of 0.86, while chemically treated CNTs (CNT-PC) presented more structurally defective CNTs and shortened nanotubes compared to other investigated treatment methods with an ID/IG value of 0.96. CNTs purified by a multi-step protocol (CNT-PAC) showed the highest weight loss of 72.3% indicating the highest quality and the presence of filamentous carbon. This study confirms that the choice of purification techniques influences the morphology and quality of plastic-derived CNTs.

PRODUCTIVE METHODS FOR INCREASING THE EFFICIENCY OF INTERMEDIATE REACTIONS IN THE SYNTHESIS OF FUNCTIONAL CERAMICS

This study focuses on investigating the potential of modified ceramic technology methods for producing composition materials with nano-level heterogeneity, approximating the properties of functional ceramics (FC) obtained through helio-technology. Three different powder synthesis methods were utilized: oxide method, ceramic technology, and sol-gel technology. X-ray diffraction and electron microscopy analyses were employed to compare the microstructure of powders obtained by these methods with samples synthesized using helio-technology. The results revealed that powders obtained through modified ceramic technology methods exhibited a more homogeneous structure and smaller particle size compared to those obtained through helio-technology. Nano-sized, metastable, and amorphous phases formed at the boundaries of such powders are considered responsible for the generation of pulsed infrared radiation. These findings have significant practical implications in various fields that require composition materials with controlled properties and the ability to generate pulsed infrared radiation.

In English

Atmospheric air pollution is determined by the functioning of both technogenic and natural sources of pollution. The main anthropogenic sources of pollution are: transport, industrial enterprises, energy facilities and agriculture. In order to select a rational and effective method of atmospheric emissions purification from harmful components, systematic study was carried out to identify the potential of natural zeolites of Georgia. In particular, four samples of zeolite-containing rocks were investigated: analcime, clinoptilolite, phillipsite, mordenite and their modified forms. By means of the chromatographic method of researching the adsorption properties of natural zeolites, the best adsorption capability of mordenite and its modified hydrogen form obtained by two methods towards nitrogen oxides has been revealed. The perspective and profitability of using the hydrogen form of mordenite treated with ammonium in the processes of purification of nitrous gases from exhaust gases is shown, as well as the possibility of using the recovered products (aqueous solutions of ammonium salts) obtained from its regeneration as a nitrogen fertilizer in agriculture. The experimental adsorption purification of the sample (H-mordenite) was carried out in the process of research. The sample was taken from the outlet pipe of the contact apparatus in the ammonia oxidation shop of the nitric acid production enterprise of LLC “Rustavi Azoti”. It has been found that the modified mordenites can be proposed as an environmentally friendly, highly efficient sorbent in the processes of air purification from toxic impurities. Of the two forms of H-mordenite investigated, the adsorption data obtained for NH4+-ion-modified mordenite is approximately 20 % better than the acid-modified form. It should be noted that the use of granulated zeolites (mordenite) in adsorbers with dense packing is very effective. It is also important from the economic point of view that it is possible to reuse spent high-silica sorbents after their regeneration by oxidation method, since such zeolites are resistant to oxidants, such as hydroxyl radicals, ozone, etc., and it is possible to regenerate them without removing them from adsorber.

Cobalt(II) mediated electro-oxidation of toluene and its derivatives

The oxidation of toluene and its derivatives is crucial for the chemical industry. Traditional liquid-phase oxidation technologies require high-temperature and high-pressure conditions, which causes high safety risks and urgently requires alternatives. This article reports an electrochemical oxidation method using cobalt acetate as a mediator, which successfully realizes the mild oxidation of toluene. The method turns toluene into highly active radicals by the electrochemically generated Co(III) from cobalt acetate, which significantly reduces the anodic potential in contrast to the direct electro-oxidation and the other reported mediated oxidation processes. The target products, benzaldehyde and benzoic acid, exhibit high yields at 85 °C as the ratio of AcO- to Co(II) is close to 2 in the homogeneous anhydrous electrolyte. A benzyl radical-centered mechanism for the Co(II) mediated electro-oxidation of toluene is proposed based on the cyclic voltammetry tests and a radical inhibiting experiment. The method has also been successfully applied to the derivatives of toluene.

Kinetic Study of Manganese Oxidative Precipitation Reaction by Using SO2/Air Gas Mixture

Removing manganese from zinc electrolytes is necessary to pave the way for replacing lead-based anodes with mixed metal oxide (MMO) anodes. MMO anodes offer significantly lower overpotential towards oxygen evolution reactions, thus are attractive from an energy consumption viewpoint. Previous studies had shown that, thanks to the catalytic effect of cobalt, manganese can be removed successfully from the zinc purification solution through the oxidative precipitation method using a simulated roasting off-gas plant. This study focuses on understanding the primary mechanism behind manganese oxidation precipitation and investigating the influence of various operating parameters such as temperature, dissolved oxygen (DO), and solution potential on the reaction kinetics. The results revealed that the kinetics of the reaction was highly dependent on the temperature and catalyst activity rather than on the reactant concentration. Additives, with radical scavenging effects, were added to identify the radicals responsible for the oxidation of Mn. The manganese oxidation reaction was dramatically suppressed when methanol was added. However, in the presence of tert-butyl alcohol (TBA), a sensible reduction in manganese removal was not observed, suggesting sulfate radical as the predominant species for oxidizing manganese. The physical and chemical characteristics of the sediments were also presented.

Integrative leaf anatomy structure, physiology, and metabolome analyses revealed the response to drought stress in sainfoin at the seedling stage.

Sainfoin (Onobrychis viciaefolia) is a vital legume forage, and drought is the primary element impeding sainfoin growth. The anatomical structure, physiological indexes, and metabolites of the leaves of sainfoin seedlings with a drought-resistant line of P1 (DRL) and a drought-sensitive material of 2049 (DSM) were analyzed under drought (-1.0 MPa) with polyethylene glycol-6000 (PEG-6000). The leaf anatomy was studied by the paraffin section method. The related physiological indexes were measured by the hydroxylamine oxidation method, titanium sulfate colorimetric method, thiobarbituric acid method, acidic ninhydrin colorimetric method, and Coomassie brilliant blue method. The metabolomics analysis was composed of liquid chromatography tandem high-resolution mass spectrometry (LC-MS/MS). The results revealed that the thickness of the epidermis, palisade tissue, and sponge tissue of DRL were significantly greater than those of DSM. The leaves of DRL exhibited lower levels of superoxide anion (O2 •-) production rate, hydrogen peroxide (H2O2) content, and malondialdehyde (MDA) content compared with DSM, while proline (Pro) content and soluble protein (SP) content were significantly higher than those of DSM. A total of 391 differential metabolites were identified in two samples. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed that the primary differential metabolites were concentrated into the tyrosine metabolism; isoquinoline alkaloid biosynthesis; ubiquinone and other terpenoid quinone biosynthesis; neomycin, kanamycin, and gentamicin biosynthesis; and anthocyanin biosynthesis metabolic pathways. Compared with DSM, DRL had more complete anatomical structure, lower active oxygen content, and higher antioxidant level. The results improved our insights into the drought-resistant mechanisms in sainfoin.

Current Advances in the Enzyme Engineering of O2‐Dependent Enzymes – Boosting the Versatility and Applicability of Oxygenases and Oxidases

AbstractOxidation reactions catalysed by O2‐dependent enzymes are gaining increasing interest in the chemical industry due to their potential to provide a more selective and sustainable alternative to conventional chemical oxidation methods. O2‐dependent enzymes, like oxidases and oxygenases, catalyse a versatile range of oxidative reactions using only molecular oxygen as an oxidant. However, their practical application on a larger scale has been limited up to this point, primarily due to factors like their low catalytic rates combined with a narrow substrate spectrum and low stability. Nonetheless, enzyme engineering studies have significantly addressed these challenges in recent years and moved O2‐dependent enzymes closer towards industrial utilisation. This review aims to concisely overview the most recent engineering approaches to O2‐dependent enzymes. We will highlight recent studies that have targeted various aspects of O2‐dependent enzymes, including activity, selectivity, stability, and substrate spectrum, focusing on engineering studies where the engineered enzymes catalysed synthetically valuable reactions.

CuO-ZnO nanocomposite for photocatalytic application

The rising levels of water pollution and climate change contribute to water shortages. These factors influence the loss of the environment’s biodiversity and threaten human health. Toxic dye pigments from industries are a significant source of pollution. In this article, we present the synthesis method, characteristics, and photocatalytic properties of the CuO-ZnO nanocomposite, which may affect the degree of decomposition of dyes found in water. The nanocomposite consisting of copper oxide nanowires with zinc oxide nanostructures (CuO-ZnO nanocomposite) was prepared by physical vapor deposition and thermal oxidation methods. The crystalline structure, surface topographies and morphologies, elemental composition, and optical properties of the obtained samples were studied with various techniques such as x-ray diffraction analysis, high-resolution transmission electron microscopy, field emission scanning electron microscopy, energy dispersive x-ray analysis, and UV-vis spectroscopy. The photocatalytic activity of the nanocomposite was measured by testing the degradation of methylene blue under visible irradiation. An increase in the photocatalytic activity of the nanocomposite was observed compared to pure CuO and ZnO. The CuO-ZnO nanocomposite demonstrated a high dye degradation of about 94% during 120 min.

Unlocking the Therapeutic Potential of Freshwater Sapropel Extracts: In Vitro Analysis and Antioxidant Profiling for Skincare Applications.

Background and Objective: Sapropel, a biologically active sedimentary deposit, is high in organic matter and minerals and has been shown to offer health benefits. Its constituents, humic acid (HA) and fulvic acid (FA), have been found to have some therapeutic applications. The aim of this study was to determine the potential therapeutically significant properties of freshwater sapropel extracts: their polyacid content, antioxidative (AO) status, and biological activity in cell culture. Materials and Methods: Freshwater lakes from the southeast region of Latvia were investigated layer by layer. The total organic carbon (TOC) was determined through combustion using the catalytic oxidation method, HA and FA were measured via acid perspiration, and the total polyphenol content (TPC) and total antioxidant status (TAS) was analysed spectrophotometrically. Sapropel extracts' regenerative abilities were tested in vitro using a Cell-IQ real-time monitoring system on mouse BALB/c 3T3 fibroblasts and human keratinocyte HaCaT cell lines. Cytotoxicity was measured through neutral red uptake assessment as a concentration-dependent reduction in the uptake of neutral red dye relative to a vehicle control or untreated cells. Results: The highest AO activity was observed in sapropel extracts with elevated concentrations of HA and TPC from Audzelu Lake (1.08 ± 0.03 mmol/L), and the lowest activity was found in extracts from Ivusku Lake (0.31 ± 0.01 mmol/L). Correspondingly, the concentrations of HA in Audzelu and Ivusku Lakes were recorded as 45.2 and 27.4 mg/g, respectively. High concentrations of HA promoted in vitro cell growth upon short-term exposure (up to 6 h). Conclusions: The results show that high TPC correlates with AO status and sapropel extracts with higher concentrations of HA exhibit greater AO activity and promote in vitro cell growth, suggesting a perspective use for short-term topical therapeutic skin applications. However, higher concentrations over longer durations showed cytotoxic effects, indicating the need for further investigation.

Effect of Ti and C addition on oxidation resistance of FeCoCrNiMn high entropy alloys prepared by powder metallurgy

Purpose The purpose of this paper is to study the high temperature oxidation behavior of Ti and C-added FeCoCrNiMn high entropy alloys (HEAs). Design/methodology/approach Cyclic oxidation method was used to obtain the oxidation kinetic profile and oxidation rate. The microstructures of the surface and cross section of the samples after oxidation were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Findings The results show that the microstructure of the alloy mainly consisted of FCC (Face-centered Cubic Structure) main phase and carbides (M7C3, M23C6 and TiC). With the increase of Ti and C content, the microhardness, strength and oxidation resistance of the alloy were effectively improved. After oxidation at a constant temperature of 800 °C for 100 h, the preferential oxidation of chromium in the chromium carbide determined the early formation of dense chromium oxide layers compared to the HEAs substrate, resulting in the optimal oxidation resistance of the TC30 alloy. Originality/value More precipitated CrC can preferentially oxidize and rapidly form a dense Cr2O3 layer early in the oxidation, which will slow down the further oxidation of the alloy.

Carbon Sequestration Potential of Manure-Derived Hydrochar Aided by Secondary Stabilization.

Hydrothermal carbonization (HTC) is a process that produces a carbon-rich solid from wet organic materials through the application of heat and pressure. Carbonized solids, previously correlated to long-term soil stability, may be considered for carbon sequestration through incorporation into soil. Chars produced by pyrolysis are known for exceptional stability in soil, but pyrolysis is expensive when applied to wet biomass, such as manure. Chars produced from manure by HTC show considerably improved potential for carbon sequestration relative to untreated manure, although not as great as that of chars produced by pyrolysis. This study focuses on producing and evaluating chars by HTC paired with pyrolysis and different methods of chemical oxidation for long-term carbon sequestration in soil. It is shown that a two-step process of pyrolysis following HTC produces a char that outperforms those produced by either individual process (HTC or pyrolysis) in carbon yield, carbon content, and, more importantly, soil carbon sequestration potential. It was found that acid-catalyzed HTC followed by pyrolysis resulted in a char with a 13% increase in carbon yield, a 51% increase in carbon content, and an atomic O/C ratio 64% smaller than the char produced by conventional pyrolysis.

Selective oxygen-doping in self-supportive carbon electrode by electrochemical oxidation for electrocatalytic synthesis of hydrogen peroxide

We report the selective introduction of oxygen-containing functional groups for two-electron oxygen reduction reaction (2e-ORR) in self-supportive carbon electrode using electrochemical oxidation method. The optimal electrode shows hydrogen peroxide (H2O2) selectivity up to 95 %. CO is found active to control 2e-ORR selectivity and mechanism of oxygen species variation is elucidated by in situ infrared reflection absorption spectroscopy. We further improve mass transfer by introducing highly interconnected macropores in electrode, which shows H2O2 yield of 144 mmol cm−2 h−1 and Faradaic efficiency of nearly 100 %. These may inspire advanced active electrode creation for applications through selective electrochemical doping and structural design.

Enhanced hydrogen barrier performance of ZrH1.8 via yttria-zirconia composite film developed through the ECD-MAO technique

To address the inherent shortcomings of the direct micro-arc oxidation method, this study employed a combination of electroplating and micro-arc oxidation techniques. This approach successfully fabricated a hydrogen permeation barrier film on the surface of ZrH1.8, featuring a yttria-stabilized zirconia (YSZ) composite oxide. The prepared composite film layer underwent thorough evaluations, encompassing assessments of its microstructure, phase structure, adhesion strength, thickness, barrier properties, and hydrogen permeation performance. The findings indicated that the electroplated yttrium layer contributes to the stabilization of the tetragonal phase of zirconia (T-ZrO2) during the micro-arc oxidation process, thereby enhancing the discharge behavior of the film layer. By employing this treatment method, the content of T-ZrO2 in the film layer increased to 26.70%, and the film became denser with a thickness of 60.93 μm. Additionally, the adhesion strength between the film layer and the substrate significantly improved, reaching 75.95 N, with a hardness of 393.24 HV. Furthermore, the film layer exhibited an increased hydrogen release temperature of 680 °C, demonstrating excellent performance as a hydrogen permeation barrier.

Oxidative Transformation of Nafion-Related Fluorinated Ether Sulfonates: Comparison with Legacy PFAS Structures and Opportunities of Acidic Persulfate Digestion for PFAS Precursor Analysis.

The total oxidizable precursor (TOP) assay has been extensively used for detecting PFAS pollutants that do not have analytical standards. It uses hydroxyl radicals (HO•) from the heat activation of persulfate under alkaline pH to convert H-containing precursors to perfluoroalkyl carboxylates (PFCAs) for target analysis. However, the current TOP assay oxidation method does not apply to emerging PFAS because (i) many structures do not contain C-H bonds for HO• attack and (ii) the transformation products are not necessarily PFCAs. In this study, we explored the use of classic acidic persulfate digestion, which generates sulfate radicals (SO4-•), to extend the capability of the TOP assay. We examined the oxidation of Nafion-related ether sulfonates that contain C-H or -COO-, characterized the oxidation products, and quantified the F atom balance. The SO4-• oxidation greatly expanded the scope of oxidizable precursors. The transformation was initiated by decarboxylation, followed by various spontaneous steps, such as HF elimination and ester hydrolysis. We further compared the oxidation of legacy fluorotelomers using SO4-• versus HO•. The results suggest novel product distribution patterns, depending on the functional group and oxidant dose. The general trends and strategies were also validated by analyzing a mixture of 100000- or 10000-fold diluted aqueous film-forming foam (containing various fluorotelomer surfactants and organics) and a spiked Nafion precursor. Therefore, (1) the combined use of SO4-• and HO• oxidation, (2) the expanded list of standard chemicals, and (3) further elucidation of SO4-• oxidation mechanisms will provide more critical information to probe emerging PFAS pollutants.

Greenly building strong interactions between epoxy and carbon fiber fabric via vapor assisted ozone

AbstractTo enhance the performance of carbon fiber reinforced polymer (CFRP), it is crucial to establish robust interactions between epoxy and carbon fiber fabric (CFF). Herein, CFF was treated by an optimized H2O2/H2O/O3 oxidation method. The chemical and physical properties of the treated CFFs were meticulously characterized. For comparison, CFF, O3 treated CFF, and H2O/O3 treated CFFs were also examined. It was found that H2O2/H2O/O3 oxidized CFF more effectively than either O3 or H2O/O3. Reactive O groups were extensively grafted onto the surface of the H2O2/H2O/O3 oxidized CFF, leading to an increase in surface energy. Additionally, numerous defects were introduced on the surface of the H2O2/H2O/O3 oxidized CFF, significantly enhancing its surface roughness. Consequently, the interlaminar shear strength of H2O2/H2O/O3 oxidized CFF reinforced epoxy composite reached 63.31 ± 2.50 MPa, which is 43.3% higher than that of CFF reinforced epoxy composite. The fracture surface morphology and differential scanning calorimetry studies confirmed the presence of strong interfacial chemical interactions, while the increased surface roughness ensured robust interfacial physical interactions. Based on these findings, the mechanisms of the H2O2/H2O/O3 oxidized CFF reinforcing epoxy were proposed. The present work aims to give out some ideas for the fabrication of green and advanced CFRP.Highlights CFF was effectively oxidized by an optimized H2O2/H2O/O3 method eco‐friendly. Improved the interlaminar shear strength of the epoxy composite by 43.3%. Both the strong interfacial chemical and physical interactions were confirmed. The reinforcing mechanism is attributed to the robust interactions.

Identification and characterization of camptothecin tailoring enzymes in Nothapodytes tomentosa.

Camptothecin is a complex monoterpenoid indole alkaloid with remarkable antitumor activity. Given that two C-10 modified camptothecin derivatives, topotecan and irinotecan, have been approved as potent anticancer agents, there is a critical need for methods to access other aromatic ring-functionalized congeners (e.g., C-9, C-10, etc.). However, contemporary methods for chemical oxidation are generally harsh and low-yielding when applied to the camptothecin scaffold, thereby limiting the development of modified derivatives. Reported herein, we have identified four tailoring enzymes responsible for C-9 modifications of camptothecin from Nothapodytes tomentosa, via metabolomic and transcriptomic analysis. These consist of a cytochrome P450 (NtCPT9H) which catalyzes the regioselective oxidation of camptothecin to 9-hydroxycamptothecin, as well as two methyltransferases (NtOMT1/2, converting 9-hydroxycamptothecin to 9-methoxycamptothecin), and a uridine diphosphate-glycosyltransferase (NtUGT5, decorating 9-hydroxycamptothecin to 9-β-D-glucosyloxycamptothecin). Importantly, the critical residues that contribute to the specific catalytic activity of NtCPT9H have been elucidated through molecular docking and mutagenesis experiments. This work provides a genetic basis for producing camptothecin derivatives through metabolic engineering. This will hasten the discovery of novel C-9 modified camptothecin derivatives, with profound implications for pharmaceutical manufacture.

Optimised and percolated nanocomposite of polyaniline/tungstic anhydride modified electrode implemented in Vanadium redox flow battery

In order to make vanadium redox flow batteries (VRFB) economically viable on a large scale, it is crucial to create graphite-based electrode nanomaterials with an excellent performance. In this research work, we synthesized the various percentage nanocomposites of polyaniline (PANI)/nano-tungsten oxide (NTO) by in situ chemical oxidative polymerization method. The impact of crystal phases, elements present in nanocomposites, thermal stability, surface analysis, and morphological factors were studied. We investigated electrochemical behavior such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel studies for PANI and NTO and prepared nanocomposites (NPATO) with different proportions sprayed over graphite felt (GF). Characterization analysis was used to examine the impact of various NTO loading concentrations on the PANI, and an ideal best percolated sample NPATO20/GF (3 mg cm−2) was inserted as a positive electrode in the cell stack to examine the charge–discharge cycles. At 60 mA cm−2 current density, their coulombic (η C), voltaic (η V), and energy (η E) efficiencies are outstanding. The concentration of 3 mg cm−2 nanoparticles on GF provided sufficient availability of active sites for electrochemical reactions, resulting in an increased electrochemical reaction. It has been proven that this work creates an affordable and efficient method for the forthcoming VRFBs.

Influence of Interfacial Interaction and Composition on Fracture Toughness and Impact Properties of Carbon Fiber-Reinforced Polyethersulfone.

In this study, the interlaminar fracture toughness and impact strength of polyethersulfone reinforced with continuous carbon fibers were studied. Interlaminar fracture toughness tests were performed using the double cantilever beam method. It was shown that surface modification using the thermal oxidation method of the carbon fibers can strongly increase the interlaminar fracture toughness of the obtained composites. Thus, the maximum value reached 1.72 kJ/m2, which was 40% higher than the fracture toughness of the composites reinforced with initial carbon fibers. Moreover, fractographic analysis using a scanning electron microscope allowed us to highlight the main reasons for the dependence of fracture toughness on fiber content and surface modification conditions of the carbon fibers. It was shown that the main factor that allowed for an increase in fracture toughness was the enhanced interfacial interaction between the fibers and polymer matrix. Additionally, it was found that expectedly, there was a good correlation between interlaminar fracture toughness and interlaminar shear strength results. However, a negative influence of surface modification on the impact properties of composites was found. Such behavior occurred because of higher structural stability and lower exposure to delamination in multiple layers of the composites reinforced with the modified carbon fibers. It was found that impact energy reached ~150 kJ/m2 for the polyethersulfone-based composites reinforced with initial fibers, while the composites reinforced with modified carbon fibers showed impact energy values of only ~80 kJ/m2. Nevertheless, surface modification of carbon fibers using the thermal oxidation method can be an effective method for improving the performance properties of polyethersulfone-based composite materials.

Adsorptive capacity of PANI/Bi2O3 composite through isotherm and kinetics studies on alizarin red

Adsorption offers numerous advantages for eliminating organic pollutants such as dyes, making it a valuable method for water treatment. Polyaniline/Bi2O3 (PANI/Bi2O3) nanocomposite is synthesized from aniline by the chemical oxidative polymerization method. The sample shows a high positive surface charge density as seen from zeta potential analysis. X-ray Diffraction analysis, FTIR analysis, UV–vis spectroscopy technique, thermogravimetric analysis, BET N2 Adsorption-desorption analysis, DLS, and zeta potential analysis are the tools employed to characterize the PANI/Bi2O3 nanocomposite. The impact of PANI/Bi2O3 on the outcome of adsorption is confirmed by comparing the composite with pristine Bi2O3 and PANI. The effect of various factors like time, temperature, initial dye concentration, and varying pH on the adsorption efficiency is studied. A maximum adsorption efficiency of 95 % is observed when 100 mg of PANI/Bi2O3 nanocomposite is utilized for a duration of 100 min. The adsorption efficiency increases at higher temperatures, and a maximum adsorption efficiency is observed at a pH of 11.4. The adsorption isotherms proposed by Freundlich and Langmuir are examined to confirm the adsorption mechanism, which entails the creation of a single layer of dye molecules on the adsorbent's surface. Analysis of kinetic parameters indicates that the reaction follows pseudo-second-order adsorption kinetics. The composite produced demonstrates effectiveness as an adsorbent for removing harmful organic pollutants from water sources.

Phase‐Transfer Catalysis for Electrochemical Chlorination and Nitration of Arenes

AbstractA biphasic anodic oxidation method for aromatic halogenation process was developed, where aqueous metal salts were directly used as halogen source. Ammonium salts serve as both electrolytes and phase transfer catalysis to facilitate anion transport and oxidative transformation. This design allows for chlorination or nitration of multiple types of arenes using NaCl or KNO2.