Catalyst Concentration Research Articles

Exploration of Biomimetic Metal-Organic Catalysts for Splitting Glucose into Dihydroxyacetone and Glyceraldehyde

Lactic acid is a metabolite produced during glucose glycolysis, typically generated industrially through the fermentation of glucose using microorganisms. However, the high production cost of this fermentation process makes lactic acid relatively expensive, rendering biodegradable plastics made from polylactic acid less competitive. This research focuses on the initial stages of glucose glycolysis process, in which glucose is split into dihydroxyacetone and glyceraldehyde, both of which are isomers of lactic acid. Biomimetic metal-organic catalysts composed of Mg-Zn tripolyphosphate, imidazole, and monosodium or monoammonium glutamate were tested in a water–acetonitrile reaction medium. Prior to catalyst testing, either water–acetonitrile or water–acetonitrile–acetone solutions were chosen as the reaction medium based on their effectiveness in producing phase separation. The study investigated the effects of catalyst concentrations, catalyst types, and reaction temperatures on glucose conversion, as well as the yield and selectivity of dihydroxyacetone and glyceraldehyde within 6 hours reaction time at pH 8. The results showed that these biomimetic metal-organic catalysts effectively facilitated the splitting of glucose in a water–acetonitrile solution, achieving the best glucose conversion of 57.16% at a temperature of 90°C with a catalyst concentration of 0.8%-mol.

Heterogeneous catalysts for electro-Fenton degradation of cytostatic drug cytarabine

In the present work, a reduced graphene oxide (rGO) modified-Fe3O4 doped bifunctional carbon felt cathode (rGO-Fe3O4/CF) that is capable of generating and converting H2O2 into hydroxyl radicals (•OH) on-site was fabricated, thus removing the need for an external catalyst. In addition, an rGO-modified cathode (rGO/CF) with high H2O2 production efficiency and a heterogeneous Fenton catalyst (CNT-Fe3O4) with magnetic properties were fabricated. The study examined the degradation and mineralization of the cytostatic drug cytarabine (CYT) using two HEF configurations: (i) a bifunctional cathode rGO-Fe3O4/CF and (ii) a combination of the rGO/CF cathode with CNT-Fe3O4 catalyst. The effects of parameters such as catalyst concentration, initial pH, and applied current were studied. HPLC and ion chromatography analyses were used to identify carboxylic acids and inorganic end-products, respectively. The results show that 0.1mM CYT was completely degraded within 18min at an applied current of 300mA in the HEF system with the rGO-Fe3O4/CF bifunctional cathode. Total organic carbon (TOC) analysis revealed that the bifunctional cathode system achieved 98.2% mineralization of CYT after 4h of treatment at 300mA. Using the rGO/CF cathode and CNT-Fe3O4 catalyst cell, total degradation of 0.1mM CYT occurred within 7min, and nearly total mineralization (97.3% TOC removal) was achieved at 300mA after 4h.

Insights into the exceptional support phase effect on Ag/Sm2Ce2O7: Modulating Ag distribution and Ag-support interaction to construct reactive soot oxidation catalysts

Developing efficient, cost-effective and robust catalysts for soot combustion is crucial yet challenging. In this study, we fabricated Ag-loaded Sm2Ce2O7 paramorphs catalysts (C-type and Cubic fluorite) via different methods, aiming to improve the distribution and interaction of Ag by modifying the crystalline structures of the supports to enhance oxygen activation. The oxygen vacancy concentration and redox performance of the rare earth C-type catalysts exceeded those of the cubic fluorite ones. In the case of the Ag-assisted catalysts, the Sm2Ce2O7–Ag interface with oxygen vacancies displayed an increased affinity for oxygen. The distribution state of Ag on the catalysts is closely related to the Ag–support interactions and the active sites on the support. Experimental analyses and density functional theory (DFT) calculations have revealed a more even dispersion of the Ag species on the C-type catalyst; differential charge density and Bader charge analysis have confirmed that the Ag loadings can alter the surface charge arrangement, resulting in stronger electronic interactions between Ag and the Sm2Ce2O7-C support. Uniformly dispersed Ag species can effectively promote the activation of gaseous O2 molecules, which is key in the oxidation of soot particles. This approach provides a promising strategy for developing more applicable catalysts for soot combustion.

In situ construction of CuBi2O4/Bi4O5Br2 Z-scheme heterojunction with enhanced photocatalytic degradation performance for polyphenolic contaminant in wastewater

Photocatalytic technique is one of the clean and promising routes for wastewater purification. In this work, a different CuBi2O4/Bi4O5Br2 Z-scheme heterojunction were successfully prepared via an in-situ mechanical agitation method. The 10% CuBi2O4/Bi4O5Br2 (10% CBO/BOB) heterojunction showed the highest photocatalytic degradation activity for catechin, and ∼99.8% catechin was degrade within 40 min visible light stimulation, which is (0.0757/min) about 6.2-folds and 8.8-folds to that of Bi4O5Br2 (0.0122/min) and CuBi2O4 (0.0086/min), The pH=7 is the optimal reaction condition for catechin degradation. Besides, The photocatalytic degradation capacity of the 10% CBO/BOB heterojunction displayed the positive and negative relationship to the dosage of catalyst and initial concentration of catechin, respectively. The enhanced photocatalytic activity of CuBi2O4/Bi4O5Br2 Z-scheme heterojunction can be ascribed to the improvement of the charge separation and light utilization rate. The results of ESR and trapping experiments revealed that the ·O2-, h+ and ·OH are the primariy reactive substances for catechin degradation. Additionally, the transfer pathway of the photogenerated charges in the CuBi2O4/Bi4O5Br2 Z-scheme heterojunction as revealed by the ESR, Mott-Schottky curve and UV-Vis diffuse reflectance absorption spectroscopy. This work provide a new idea for designing and preparing the novel Bi4O5Br2-based photocatalyst for TCM wastewater purification.

Flexible and Stretchable Vitrimers for Sustainable Electronics.

The rapid increase in electronic waste (e-waste) necessitates sustainable materials that combine functionality with recyclability. Here, we introduce a novel approach for creating flexible vitrimers─reprocessable polymers with dynamic covalent bonds─for use in electronic applications, such as wiring and connectors. By extending polymer chains and employing transesterification reaction, we develop vitrimers that exhibit tunable viscoelastic properties, high stretchability (over 250% tensile strain), and enhanced toughness (up to 466 J/m3). Our vitrimers demonstrate a topological freezing temperature (Tv) of 185-248 °C, adjustable through catalyst concentration and chain length. The materials are synthesized by using a two-step process involving widely available industrial chemicals. Molecular dynamics simulations provide insight into how chain extension and network topology affect viscoelasticity, supporting the experimental findings. Using transesterification, covalent bonding between flexible and rigid vitrimers can be achieved. We prototype a functional USB cable that successfully transfers power and data, showcases repairability, and is recyclable through a solvent-based process. These results highlight the potential of flexible vitrimers in reducing e-waste and advancing sustainable electronic manufacturing.

Response surface methodology for glucose conversion by applying deep eutectic solvent (DES) as green solvent

Glucose is a monosaccharide-type carbohydrate that serves as a fundamental building block of biomass. In this research, glucose was hydrolyzed using a Deep Eutectic Solvent (DES) as the solvent and AlCl3 as the catalyst. The effects of temperature and catalyst concentration were investigated as key variables in the reaction. The glucose conversion results were tested using the UV-Vis spectrophotometer. The yields of glucose conversion were analyzed using the Response Surface Methodology (RSM) with Design Expert Version 13 software. The results of RSM analysis show that glucose conversion increases linearly with rising reaction temperature. The effect of catalyst concentration indicates that glucose conversion decreases at higher catalyst levels. The reaction temperature and AlCl3 catalyst concentration that can be recommended for optimum conditions from the Design Expert data processing results are 112.869 C and 1.913% with a predicted conversion value of 93.844%.

Hydrogen generation through metal waste corrosion: a systematic investigation on old/post-consumer scrap Al6063-series alloy

In this study, aluminum-based wastes are used as energy carriers for on-demand hydrogen production through sustainable, eco-friendly, and cost-effective controlled electrochemical corrosion in aqueous solution. The electrochemical process is very effective because it (i) uses waste metals to produce hydrogen, (ii) corroborates to circular economy, (iii) produces high purity hydrogen, (iv) is based on simple hydrolysis reaction of metals in relevant solutions, (v) electricity is not required and (iv) recovers part of the chemical Gibbs energy of the electrochemical corrosion usually entirely lost in the environment. We systematically studied the generation of hydrogen from industrial waste Dust Scrap Aluminum Alloy (DSAA) belonging to Al 6063 series for the first time. The process is investigated in a novel hand-made batch reactor with a low-cost commercial body suitable to an easy scale-up. Kinetics of DSAA hydrolysis reaction was explored by measuring the variation of aluminium ion concentration at different immersion times through Inductively Coupled Plasma (ICP) and weight loss measurements at different temperatures and NaOH catalyst concentrations. The effect of hydrolysis reaction on the composition and morphology of the metal surfaces in terms of formed oxide layers was studied in detail using Optical Polarizing Microscopy (OPM), Energy dispersive X-ray (EDX) and Scanning Electron Microscopy (SEM) techniques. The criteria used to evaluate the hydrogen reactor performance were hydrogen (i) yield and (ii) production rate. The experimental results showed that a strong increase in NaOH concentration (from 0.75 to 5 M) corresponding to a slow increase in hydrolysis reaction temperature (from 38.8 to 49.9 °C) lead to an improvement in hydrogen generation rate of one order of magnitude, i.e. from 35.71 to 421.41 ml/(g∙min). Low but constant rate of hydrogen can be generated for longer times at low NaOH concentrations (0.75 M), while fast and variable hydrogen generation rate occurs at higher concentrations (5 M) in short times. In the case study of Al 6063 series waste scrap, the hydrolysis reactor parameters can be regulated to deliver hydrogen generation rates from 35.71 to 421.41 ml/(g min) according to requirements. We expect that the results presented in this work will encourage researchers to study the possible use of other metal-based and multi-material plastic/metal wastes thermodynamically prone to electrochemical corrosion process as possible source of hydrogen.Graphical

Oxidative oligomerization of a synthetic fraction of hydrocarbons from the Fischer-Tropsch synthesis

The work investigated the process of oxidative oligomerization of Fischer-Tropsch synthesis products - a fraction of C10-C15 hydrocarbons with a total content of alkenes (mainly β- and γ-alkenes) of 64.7 wt. % using zirconium octoate as a catalyst. The hydrocarbon fraction was obtained on a zeolite-containing catalyst at a pressure of 2.0 MPa, a temperature of 250 °C, H2/CO ratio at the reactor inlet of 1.70, a gas space velocity of 1000 h-1 and circulation mode ratio range 0-16. It was found that at a temperature of 160 °C the catalyst content is 5.0 wt. %, process duration 6 hours and pressure (air) - 2.5 MPa, target fraction yield - 52.7 %. It was found that the oligomerization product has a low pour point of minus 31 °C. It was proposed to improve the viscosity characteristics of the oligomerization product by introducing additives into its composition, for example, polymethacrylates or polyisobutylene.

A Comparative Study of Advanced Oxidation Processes for the Removal of the Antibiotic Sulfadoxine from Water—Transformation Products and Toxicity

Sulfonamides, including sulfadoxine (SDX), are widely used antibiotics, particularly for malaria treatment. However, their extensive use has led to environmental pollution, microbial resistance, and public health risks. Advanced Oxidation Processes (AOPs) offer promising methods to degrade such pollutants in water, though they may generate more toxic by-products. This study evaluates three AOPs with different hydroxyl radical generation principles: the Fenton reagent (H2O2/Fe2+), hydrogen peroxide photolysis (UV-C/H2O2), and heterogeneous photocatalysis (UV-A/TiO2). Heterogeneous photocatalysis showed superior performance, achieving 100% degradation and 77% mineralization under optimized conditions. Further analysis explored the effects of UV dose, catalyst concentration, and pH on process efficiency. The influence of water matrices, including Ultrapure Water (UW), Tap Water (TW), and Surface Water (SW) from the Aliakmonas River, was also examined. High-Resolution Mass Spectrometry identified 11 SDX transformation products formed during photocatalysis, with their formation mechanisms reported for the first time. An ecotoxicity assessment using ECOSAR software revealed insights into the potential environmental impact of these by-products.

Dual Activation Modes Enable Bifunctional Catalysis of Aldol Reactions by Flexible Dihydrazides.

Hydrazides are known to catalyze reactions of α,β-unsaturated aldehydes via transient iminium formation. The iminium intermediate displays enhanced electrophilicity, which facilitates conjugate additions and cycloadditions. We observed that a hydrazide embedded in a seven-membered ring catalyzes homoaldol condensation of a simple aldehyde in a process that displays an approximate second-order dependence on the hydrazide. This finding suggests a dual activation mechanism involving both iminium and enamine intermediates. The unexpected nucleophilic activation mode led us to examine a series of simple dihydrazides for bifunctional catalysis of the aldol condensation. The two cyclic hydrazide units were connected via linear polymethylene linkers, which are inherently flexible. Substantial increases in initial reaction rate, relative to a monohydrazide, were observed for polymethylene linkers of sufficient length, with a maximum at 10 methylenes. Reactions promoted by this dihydrazide displayed an approximate first-order dependence on catalyst concentration, which suggested a bifunctional catalytic mechanism. Even for a dihydrazide with an 18-methylene linker, a substantial increase in relative initial rate was observed. These observations show that significant coordination can be achieved between two catalytically active moieties even when these moieties are connected via many flexible bonds.

RSM modelling and yield prediction of base-catalyzed transesterification of pumpkin-seed oil to biodiesel: artificial neural network, kinetics, and thermodynamics

The study examined the extraction of bio-oil from pumpkin seed and compared the optimization of the production of Fatty acid ethyl ester (FAEE) via the transesterification process using Response Surface Methodology (RSM), and Artificial Neural Network (ANN). This research uniquely highlights the utilization of pumpkin seed oil, a non-edible and sustainable feedstock, and combines RSM and ANN methodologies to enhance the precision of biodiesel optimization. The transesterification experiment was conducted at 60 min reaction time under varying temperature ranges, catalyst weight, stirrer speed, and ethanol-oil molar ratio. The RSM optimized conditions for maximum production were determined to be a 1.3% catalyst concentration, 6:1 ethanol-to-oil molar ratio, 50 °C temperature, and 550 rpm stirrer speed, resulting in a 90% biodiesel yield. The statistical evaluation metrics confirmed the neural network predictions were compromised to 80% yield due to limitations such as insufficient data size and the inherent complexity of the ANN model. The biofuel produced satisfied ASTM specifications peculiar to sustainable environmental applications. The mechanistic parameters revealed variations in thermodynamic stability and feasibility across reaction orders (zero, pseudo-first, and pseudo-second), emphasizing the temperature-dependent effects of the transesterification kinetic pathway on yield, design, and efficiency.

Studies of biodiesel production using various blends of waste palm cooking oil and castor oil

This study has been conducted using blends of castor oil (CO) and waste palm cooking oil (WPCO) in different proportions to enhance % yield of biodiesel via transesterification. The effects of various blending ratios of WPCO: CO (wt.%), molar ratios of methanol: oil, catalyst concentrations (wt.%), reaction time, reaction temperature and various co-solvents have been investigated to determine the optimal conditions for transesterification reaction. Maximum % yield of biodiesel is obtained at 75:25 (wt.%) of WPCO:CO blend, 9:1 methanol to oil ratio, 1 wt.% KOH catalyst, reaction temperature of 32°C, reaction time of 30 min, using n-hexane as co-solvent. The highest obtained biodiesel yield is 96%. Analysis confirmed 25 FAME components, and the fuel met ASTM standards. Blending non-edible feedstocks for biodiesel production is a sustainable approach to reduce costs and environmental impact.

Facile synthesis of CQD/g-C3N4 as a highly effective metal-free photocatalyst for the degradation of carmoisine and indigo carmine dye

The development of extensive dye pollution in the water ecosystem seriously endangers the health of the living organism. For effectively eradicating dyecontaminants from water bodies, photocatalysis is consideredan effective, energy-consumption, inexpensive disinfection technique. As an alternative to conventional metal-based catalysts, heterogeneous metal-free photocatalysts are more sustainable and kinder to the environment. Here, we reported the simplehydrothermalchemical production of Carbon Quantum dots (CQD)-doped graphitic carbon nitride(GCN). Analytical instruments such as XRD, SEM, FE-SEM, HR-TEM, EDX, FT-IR, thesurface area of BET analysis, photoluminescence, and UV–vis spectroscopy, zeta potentialwere used to characterize the as-prepared CQD doped GCN (CDCN). The degradation studies reveal that the CDCN catalyst displays the highest rate of degradation performance than pure GCN. Within 60 min, it shows 96 % degradation toward indigo Carmine (IC) and 93 % decomposition towards carmoisine dye (CM). Significant e−/h+ separation, an increased surface area, and a high redox potential capacity to induce charge bears may all contribute to the CDCN catalyst’s enhanced photocatalytic degradation efficiency. The efficiency of the photocatalytic process was optimized by studying and altering many variables. These include Dye concentration, catalyst concentration, and variation of the pH solution were some of these. The nanocomposite exhibited excellent stability after three successive runs of the photocatalytic procedure. According to the kinetics analysis results indicate that the photocatalytic decomposition of Indigo Carmine (IC) and carmoisine (CM) dye follows pseudo-first-order kinetics. For better photodegradation performance, a potential photocatalytic method employing several pairs of electron-hole acceptor scavengershas been put forth. Based on the positionsof the band gap and the result of the characterization, a feasible mechanismpathway for charge carriers was also presented.

Polyoxometalates ionic liquids based magnetic nanocomposites as an efficient heterogeneous catalysts for oxidation of thiobenzoic acid and dibenzothiophene by employing RP-HPLC-UV

Sulfur compounds need to be effectively rejected from fuel to maintain a clean environment. The removal of sulfur compounds from thiocompounds has received increased attention due to the negative environmental and industrial consequences of sulfur emissions. We examine the effectiveness of polyoxometalate (POM) ionic liquid-based nanocomposites as catalysts for the oxidative desulfurization of thiobenzoic acid and other sulfur-containing chemicals. Na-POMIL@NCP and Cr-POMIL@NCP were synthesized and thoroughly characterized using a variety of analytical techniques, including Fourier-transform infrared spectroscopy (FT-IR), UV–visible spectroscopy, powder X-ray diffraction (P-XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), fluorescence spectroscopy, and vibrating sample magnetometer (VSM). POMIL-based nanocomposites with Fe3O4@SiO2 exhibit both catalytic activity and adsorption capability. To evaluate sulfur removal efficiency and investigate the transformation paths of the thio compounds, high-performance liquid chromatography (HPLC) was performed at 33 °C using a C18 column with an acetonitrile–water mobile phase (1:1 ratio). The catalytic conversion of thiobenzoic acid and dibenzothiophene occurs at temperature, oxidant O/S ratio and catalyst concentration were investigated to determine the best catalyst for a given process. Under moderate conditions, this work proposes a cost-effective and ecologically acceptable approach for thiobenzoic acid (TB) and dibenzothiophene (DBT) production employing H2O2 as an oxidant and Na-POMIL@NCP and Cr-POMIL@NCP as heterogeneous catalysts. They are highly effective for oxidizing sulfur compounds included in diesel to lower the sulfur levels of fuel. This study provides to the development of innovative materials for ecologically friendly sulfur removal applications.

TRANSACETALIZATION OF GLYCEROL WITH 2,2-DIMETHOXYPROPANE USING ZEOLITES UNDER MILD CONDITIONS

The acetalization or transacetalization reactions produce acetals or ketals used in cosmetics, food, pharmaceuticals, and fuel additives. Besides synthesizing several products, the acetalization or transacetalization reactions can protect carbonyl groups, 1,2 and 1,3-diols in multi-step synthesis. This work studies the transacetalization of glycerol with 2,2-dimethoxypropane (2,2-DMP) to yield 2,2-dimethyl-4-hydroxymethyl-1,3-dioxolane (solketal) by catalyzing with USY, HBeta, and HZSM-5 zeolites under cleaner and mild reaction conditions (reaction temperature: 25 °C; 2,2-DMP/glycerol molar ratio: 1; reaction time: 1 h; and catalyst concentration: 0.05-5 wt.%). For catalyst concentration equal to or greater than 2,5 wt.%, glycerol conversion stabilized near 96-97% for the three zeolites tested. The product selectivities also assume a constant value, close to 97% for solketal. For the lowest concentration of catalyst, the influence of the zeolite properties on the glycerol conversion, such as acidity and the strong/weak acid site ratio, was observed. Concerning the selectivity of the products, the results suggested that it can be based on zeolite topology, active sites at the particle surface, and the relative amount of micro and mesoporous HBeta, the most selective catalyst for acetals production, was reused at least once without loss of activity and selectivity.

Synergetic efficiency: in situ growth of a novel 2D/2D chemically bonded Bi2O3/Cs3Bi2Br9 S-scheme heterostructure for improved photocatalytic performance and stability.

Adverse reactions caused by waterborne contaminants constitute a major hazard to the environment. Controlling the pollutants released into aquatic systems through water degradation has been one of the major concerns of recent research. Bismuth-based perovskites have exhibited outstanding properties in the field of photocatalysis. Nonetheless, many proposed bismuth-based perovskites still suffer from stability problems. The present study investigated a unique bismuth-based metal-co-sharing composite of 2D Bi2O3/Cs3Bi2Br9 nanosheet perovskite synthesized via a modified anti-solvent reprecipitation method. Several samples were prepared using different ratios of Bi2O3 and Cs3Bi2Br9. The optimal composite sample was found to be BO/CBB 28%, where 2D stacked nanosheets of Cs3Bi2Br9 showed remarkable interaction with Bi2O3 due to its optimal Bi co-sharing, as displayed in the FE-SEM and HRTEM images. However, further increasing the percentage led to greater agglomeration, hindering the photocatalytic degradation efficiency. The average size and optical band gap energy of the optimal sample were 42.5 nm and 2.46 eV, respectively. The photocatalytic degradation of MB using the optimal sample reached ∼92% within 60 min with a catalyst dosage of 10 mg L-1. With an increase in catalyst concentration to 40 mg L-1, MB removal reached almost ∼96% within 60 min under visible light owing to the enhanced stability, facilitating efficient charge separation. This paper presents an improved composite with optimal ratios of 2D Bi2O3/Cs3Bi2Br9 nanosheets that demonstrated good stability and enhanced photocatalytic performance in comparison with pure Bi2O3 and Cs3Bi2Br9. This study also sheds light on the significance of metal co-sharing and the pivotal role it plays in enhancing the S-scheme charge transfer and the internal electric field between the two components.

Integrating machine learning to uncover homogeneous catalytic mechanisms in N‐vinyl‐pyrrolidone synthesis

AbstractCombining machine learning, density functional theory (DFT) calculation, and kinetic modeling offers significant advantages in studying reactions under complex conditions, enabling a detailed exploration of reaction mechanisms. Artificial neural network (ANN) models accurately predict and analyze the impact of reaction conditions, overcoming the limitations of traditional kinetic studies in complex systems. Specifically, the homogeneous catalytic reaction for synthesizing N‐vinylpyrrolidone from pyrrolidone and acetylene, which has stringent requirements, was selected. The ANN model effectively captured nonlinear relationships between residence time, moisture content, reaction temperature, catalyst concentration, reaction pressure, and catalyst preparation temperature. DFT calculations revealed the reaction pathways, leading to the development of a high‐precision predictive model. This approach not only uncovers potential reaction pathways and intermediates in complex reaction systems but also provides a new avenue for optimizing reaction conditions, resulting in more efficient catalyst design and process development in intricate reaction environments.

In Situ Preparation of Silver Nanoparticles/Organophilic-Clay/Polyethylene Glycol Nanocomposites for the Reduction of Organic Pollutants.

This work focuses on the preparation and application of silver nanoparticles/organophilic clay/polyethylene glycol for the catalytic reduction of the contaminants methylene blue (MB) and 4-nitrophenol (4-NP) in a simple and binary system. Algerian clay was subjected to a series of treatments including acid treatment, ion exchange with the surfactant hexadecyltrimethylammonium bromide (HTABr), immobilization of polyethylene glycol polymer, and finally dispersion of AgNPs. The molecular weight of polyethylene glycol was varied (100, 200, and 4000) to study its effect on the stabilization of silver nanoparticles (AgNPs) and the catalytic activity of the resulting samples. The results showed that the catalyst with the highest molecular weight of polyethylene glycol had the highest AgNP content. Catalyst mass, NaBH4 concentration, and type of catalyst were shown to have a significant influence on the conversion and rate constant. The material with the highest silver nanoparticle content was identified as the optimal catalyst for the reduction of both pollutants. The measured rate constants for the reduction of methylene blue (MB) and 4-nitrophenol (4-NP) were 164 × 10-4 s-1 and 25 × 10-4 s-1, respectively. The reduction of MB and 4-NP in the binary system showed high selectivity for MB dye, with rate constants of 64 × 10-4 s-1 and 9 × 10-4 s-1 for MB and 4-NP, respectively. The reuse of the best catalyst via MB dye reduction for four cycles showed good results without loss of performance.

Eco-Friendly Synthesis of Quinazoline Derivatives Through Visible Light-Driven Photocatalysis Using Curcumin-Sensitized Titanium Dioxide.

This study explores a sustainable method for synthesizing quinazoline derivatives through visible light-driven photocatalysis using curcumin-sensitized titanium dioxide (TiO2) nanoparticles. A one-pot, three-component reaction involving aldehydes, urea/thiourea, and dimedone was utilized to efficiently produce quinazoline compounds. The photocatalytic performance of curcumin-sensitized TiO2 (Cur-TiO2) was compared to pure TiO2 (P-TiO2), with Cur-TiO2 showing significantly enhanced activity. Under optimized conditions-light intensity of 100 mW/cm2, catalyst concentration of 1 mg/mL, and a reaction time of 40 min-a 97% product yield was achieved. The Cur-TiO2 catalyst demonstrated excellent reusability, maintaining high efficiency over four consecutive cycles with minimal performance loss. This work underscores the potential of natural dye sensitization to extend light absorption of TiO2 into the visible spectrum, providing an eco-friendly and cost-effective approach to sustainable organic synthesis.

Sonocatalytic degradation of RB-5 dye using ZnO nanoparticles doped with transition metals

In this study, ZnO was doped and co-doped with rhodium and tungsten to assess the impact of these transition metals on the sonocatalytic degradation of reactive black 5 azo dye (RB-5). Structural analysis revealed that doping ZnO with 1% Rh and W does not alter its wurtzite hexagonal structure, although minor changes in cell parameters were observed due to differences in electronic density. Interestingly, co-doping resulted in lower degradation efficiency than single doping, with W-ZnO emerging as the most effective catalyst, achieving 100% RB-5 degradation within 60 min, likely due to a higher density of oxygen vacancies and hydroxyl groups. Moreover, a 2k factorial design identified optimal sonocatalytic conditions for W-ZnO, including a catalyst concentration of 0.75 g/L, a power tip of 225 W, and a hydrogen peroxide volume of 27 μL. The findings highlight the potential for doped ZnO nanoparticles in advanced oxidation processes and green chemistry applications, making this method an environmentally friendly alternative for wastewater treatment.