Photocatalyst Dosage Research Articles

Enhanced performance of hierarchical heterostructures CuS@ZnS-Ag-doped core–shell quantum dots towards photocatalytic degradation of pesticide contaminants in aqueous solution

ABSTRACT In recent years, the pollution of the water by pesticides has become a significant global concern due to the harmful effects these compounds have on human health and the environment. Therefore, removal of pollutants or making them ineffective is necessary for life. In this study, removal of agricultural pesticides such as Deltamethrin, Flumethrin and Phoxim was performed through photodegradation process using CuS@ZnS-Ag quantum dots as photocatalyst. The synthesised CuS@ZnS-Ag heterojunction nanocomposite has suitable charge separation and low electron–hole recombination rate with good optical properties. The synthesised photocatalyst was characterised by various techniques such as X-ray diffraction, Fourier transform infrared spectrometry, UV-Visible spectroscopy, field emission scanning electron microscopy and transmission electron microscopy. The effects of pH, temperature, photocatalyst dose and agitation rate on the degradation were investigated. The optimised conditions were obtained as follows: pH 7 (±0.5), temperature 30 (±2) °C, photocatalyst dose for Flumethrin 30 mg/L, Deltamethrin 10 mg/L and Phoxim 15 mg/mL and agitation rate 500 rpm. Results showed that under optimal conditions, the CuS@ZnS-Ag as photocatalyst can degrade 96% of the pollutants using light-emitting diode lamp. Kinetic studies indicated the pseudo-second-order model.

BiVO4/sulfur-doped g-C3N4 nanocomposite as photocatalyst for degradation of ciprofloxacin under visible light irradiation

In recent years, the use of antibiotics has greatly increased, which has caused environmental pollution. We offer a photocatalyst based on BiVO4/sulfur-doped g-C3N4 nanocomposite, which was made by a one-step thermal condensation method from thiourea and bismuth vanadate to degradate ciprofloxacin (CIP). The BiVO4/sulfur-doped g-C3N4 photocatalyst was analyzed by certain techniques including XRD, FTIR, BET, FESEM, EDX, TEM, DRS, photoluminesence, and Mott-Schottky to determine various physicochemical properties. The photocatalytic degradation of CIP, as a model pollutant, under visible LED light irradiation was tested to investigate the catalytic performance of nanocomposite. Response Surface Methodology (RSM) was employed to optimize operational parameters, including photocatalyst dosage (50–150 mg), CIP concentration (10–30 mg/L), initial pH of the solution (3–11), and irradiation time (12–120 min). The BiVO4/sulfur-doped g-C3N4 nanocomposite, with a narrow bandgap of 2.15 eV, exhibited exceptional photocatalytic performance in degrading CIP. The optimal conditions for CIP removal were photocatalyst dosage of 120.9 mg, CIP concentration of 10 mg/L, and initial solution pH of 3, resulting in 93.5 % removal efficiency after 105 min of irradiation. The photocatalytic degradation kinetics of CIP followed a pseudo-first-order model with a rate constant (K) of −0.0221 L/min, indicating rapid degradation process. The photocatalyst maintained excellent performance after 5 reuses, with only a 3 % reduction in efficiency. XRD analysis confirmed the structural stability of the nanocomposite after reuse.

Optimization of the dosage of ZnO photocatalyst for the degradation of sunlight driven multi dose organic dye brilliant green

In this study, we prepared ZnO nanocrystals using a chemical precipitation approach with different precursor concentrations for optimization. The structural, optical, and morphological properties of the synthesized nanocrystals were analyzed. Sunlight-driven photocatalysis was investigated for its ability to degrade a low concentration (70 ppm) of brilliant green (BG) dye using the optimized ZnO at different dosages (0.05, 0.1, and 0.15 g). Among the different dosages of ZnO, it was noted that at a low catalyst concentration of 0.05 g, the degradation efficiency was only 58.47 % even after 120 min of light exposure. When the concentration increased to 0.1 g, the rate of degradation reached 95.33 % within 90 min. At a higher dosage of 0.15 g, only 86.26 % degradation was recorded within 90 min, indicating that the optimal catalyst dosage was 0.1 g. To investigate how the dye dosage affected the degradation efficiency of the catalyst, experiments were performed using higher dye concentrations of 100 and 120 ppm with 0.1 g of catalyst. As the dye concentration was increased, the degradation rate decreased. Tests were conducted using different scavengers, including EDTA (a hole scavenger), benzoquinone (a superoxide radical scavenger), and isopropyl alcohol (a hydroxyl radical scavenger), to determine which free radical was mainly breaking down BG. In the presence of EDTA, the degradation ability of the catalyst decreased to 35 %. When the superoxide radical scavenger benzoquinone was used, the degradation efficiency decreased to approximately 22 %. On the other hand, the hydroxyl radical scavenger IPA reduced the degradation efficiency to 13 %. Based on the above discussion, the synergistic effect of holes and superoxide radicals is mainly responsible for the degradation of brilliant green. To test the practical use of the ZnO catalyst, we conducted an experiment to assess its reusability. Even after the third cycle, the ZnO exhibits 94 % degradation, confirming its reusability.

CdSe nanoflower as a new near infrared-activated photocatalyst for remediation of pharmaceutical wastewaters

Photocatalysis using Near Infrared (NIR) light is a promising method for a wide range of applications from environmental remediation. For this purpose, a flower-like cadmium selenide (CdSe nanoflower), as a new promising NIR-activated photocatalyst, was synthesized through a hydrothermal process and characterized using various spectroscopic and microscopic analytical techniques. The characterization results indicated that CdSe nanoflower is classified as an n-type semiconductor with a direct band gap of 1.7 eV (i.e., ECB = −0.7 V and EVB = 1 V indicated by Mott-Schottky analysis), and crystallite size and strain of 9.17 nm and 2.14, respectively. In the presence of various scavengers, the production of reactive oxygen species decreases, resulting in lower degradation efficiency. To investigate the photocatalytic efficacy, sulfamethoxazole (SMX) was used as a model pollutant drug molecule. The optimization of the process revealed that over 98% of SMX could be degraded under NIR irradiation and optimal conditions (pH = 7, photocatalyst dosage = 0.1 g, SMX concentration = 40 mg/L, time = 60 min), where Lagergren model with a correlation coefficient of 0.9765 was the best kinetic model describing the empirical results. The study indicates that CdSe nanoflower can be reused and regenerated up to 7 times with a 12% decrease in performance and after 60 min of degradation, the TOC concentration decreased by 81% in the best conditions. Additionally, CdSe nanoflower showed photodynamic microbial inactivation efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under NIR light irradiation, where almost 95 and 99 % of bacteria was reduced in 20 min. The results of this work show CdSe nanoflower has great potential as a photocatalytic material with antimicrobial properties in the context of wastewater treatment and the management of microbial infections.

Synthesis of Ag/CuS doped mineral magnetite nanocomposite with improved photocatalytic activity against tetracycline and diclofenac pollutants

The contamination of water sources by pharmaceutical pollutants presents significant environmental and health hazards, making the development of effective photocatalytic materials crucial for their removal. This research focuses on the synthesis of a novel Ag/CuS/Fe₃O₄ nanocomposite and its photocatalytic efficiency against tetracycline (TC) and diclofenac contaminants. The nanocomposite was created through a straightforward and scalable precipitation method, integrating silver nanoparticles (AgNPs) and copper sulfide (CuS) into a magnetite framework. Various analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR),ultraviolet–visible spectrophotometry (UV–Vis) and energy-dispersive X-ray spectroscopy (EDS), were employed to characterize the structural and morphological properties of the synthesized material. The photocatalytic activity was tested by degrading tetracycline and diclofenac under visible light. Results indicated a marked improvement in the photocatalytic performance of the Ag/CuS/Fe₃O₄ nanocomposite (98%photodegradation of TC 60 ppm in 30 min) compared to both pure magnetite and CuS/Fe₃O₄. The enhanced photocatalytic efficiency is attributed to the synergistic interaction between AgNPs, CuS, and Fe3O4, which improves light absorption and charge separation, thereby increasing the generation of reactive oxygen species (ROS) and promoting the degradation of the pollutants. The rate constant k of photodegradation was about 0.1 min−1 for catalyst dosages 0.02 g. Also the effect of photocatalyst dose and concentration of TC and pH of solution was tested. The modified photocatalyst was also used for simultaneous photodegradation of TC and diclofenac successfully. This study highlights the potential of the Ag/CuS/Fe₃O₄ nanocomposite as an efficient and reusable photocatalyst for eliminating pharmaceutical pollutants from water.

A new Zn(II)-based 3D MOF with PCU-like topology: Potent photocatalyst for nitrofurazone antibiotic degradation

Metal-organic frameworks (MOFs), a sub-class of coordination polymers, are versatile multidimensional materials that have the potential to serve as photocatalysts for the degradation of antibiotics found in wastewater. Herein, a new three dimensional (3D) Zn(II)-based MOF [Zn(TA)(bpyp)·3H2O] (1) (bypy = 2,5-bis(pyrid-4-yl)pyridine; H2TA = terephthalic acid) has been synthesized and characterized. The MOF 1 shows a 3D PCU-like topology and exhibits semiconducting properties with band gap of 3.34 eV and hence used as a photocatalyst for photodegradation of antibiotics viz. sulfasalazine (SLA), nitrofurazone (NFZ) and furazolidone (FZD) under simulated UV light irradiation. The photocatalytic results suggest that MOF 1 exhibits best photocatalytic activity for the photodegradation of nitrofurazone (NFZ) in 60 min time-span. The effects of initial concentration of NFZ, and photocatalyst dosage have been monitored for the photocatalytic performance of 1. The radical trapping experiments suggest that (holes) h+ and superoxide radical (O2·−) collectively catalyzes the photodecomposition of antibiotics. The possible mechanism for the antibiotic degradation by photocatalyst 1 have been proposed by integrating experiment with density of states (DOS) calculations and Hirshfeld surface analysis.

Synthesis and characterization of CuCoFe2O4@GA/AC as a bio-based matrix magnetic nano-heterogeneous photocatalyst for ceftriaxone degradation from aqueous media

Emerging contaminants such as ceftriaxone are a significant issue in the environment. They have led to a series of ecological, environmental, and health issues, and it is urgent to find a green and secure method to remove antibiotics from water effectively. In this research, the CuCoFe2O4@Gum Arabic (GA)/Activated Carbon (AC) as an innovative bio-based matrix magnetic nanocatalyst was synthesized for the efficient degradation of ceftriaxone from aqueous media. The structure of CuCoFe2O4@GA/AC was characterized via FESEM, EDS, Mapping, XRD, FTIR, VSM, and DRS analyses. The structural analysis of the catalyst revealed its synthesis at the nanometer scale (40–50 nm), exhibiting high magnetic strength (Ms: 5.38 emu/g) and favorable optical properties with a bandgap of 3.6 eV. Under optimized conditions, including a pH of 5, 60 min of irradiation time, 0.24 g/L photocatalyst dose, and ceftriaxone concentration of 5 mg/L, the removal efficiency from synthetic and real samples was 94.43% and 62.5%, respectively. The photocatalytic degradation process of ceftriaxone followed pseudo-first-order and Langmuir–Hinshelwood kinetic models. Furthermore, analysis of the process mechanism indicated a prominent role of the superoxide radical. The catalyst had a high recovery capability and chemical stability. The photocatalytic degradation of ceftriaxone by CuCoFe2O4@GA/AC showcased remarkable efficiency, indicating its potential utility in the treatment of wastewater contaminated with antibiotics.

Two new transition CdII and MnII-based MOFs for highly effective photodegradation antibiotics

Two coordination polymers (CPs), [Cd3(L)3(phen)2]n (1) and [Mn(L)(phen)]n (2), [H3L=3,3′-(1,4-phenylenebis(methylenoxy)dibezoic acid] were synthesized via hydrothermal method. 1 features a 2D layered structure with the potential for 3D network formation through weak interactions, 2 exhibits a 1D waved chain capable of forming 3D polymeric chains via intra- or intermolecular hydrogen bonding (OH···O) interactions. Both CPs demonstrate promising photocatalytic activity against antibiotics, including chloramphenicol (CAP), metronidazole (MDZ), nitrofurazone (NFZ), oxytetracycline (OXY), and sulfamethazine (SMZ). Notably, CP 1 shows superior photocatalytic activity for NFZ degradation. Systematic investigations revealed that under optimized conditions, CP 1 achieves a remarkable ∼ 92.21 % photodegradation of NFZ at a concentration of 40 ppm NFZ with a photocatalyst dosage of 25 mg/L within 50 min. Radical quencher experiments identified h+ (positive holes) and O2•- as the primary active species driving the photodegradation process. Additionally, CP 1 maintained consistent performance over five cycles, indicating its stability and reusability for NFZ degradation.

Investigating the Z-scheme mechanism on the optimized oxygen vacancies ZnO/Co3S4 photocatalyst for the efficient photocatalytic removal of ciprofloxacin

The waste of human and animal antibiotics is an inescapable problem and a severe threat to the continuation of human life. A logical strategy to face the challenge of antibiotic contamination is to design active, stable, environmentally friendly, and economical photocatalysts. Hence, oxygen vacancies ZnO/Co3S4 (ZnO-OV/Co3S4) photocatalyst was successfully fabricated for the first time and used for the photocatalytic removal of ciprofloxacin (CIP) as a widely used antibiotic under visible light. Several techniques were engaged in exploring the crystallinity, morphology, structure, chemical and elemental composition, and electrochemical and optical properties of the constructed nanocomposites. The band gap of ZnO-OV and Co3S4 nanoparticles was determined at 2.95 and 1.58 eV by evaluating the optical properties and using the Tauc plots. To optimize the conditions of the photocatalytic process, factors such as the weight percentage of the nanocomposite components, the photocatalyst dosage, the initial concentration of CIP, the pH of the test solution, and the presence of bubbled oxygen were varied. The optimal degradation rate constant (0.0720 min−1) was obtained for ZnO-OV/Co3S4 (15 %) nanocomposite at pH 9, nanocomposite dosage of 1.5 g/L, and 10 mg/L of CIP in the visible spectrum. The experimental and characterization outcomes indicated that the significantly boosted photocatalytic activity of the ZnO-OV/Co3S4 composite was chiefly attributed to the oxygen vacancies, retard charge carriers recombination by the construction of heterojunction between the ZnO-OV and Co3S4. Finally, the possible Z-scheme mechanism was proposed to illuminate the migration of charge carriers.

Optimization of degradation of potassium ethyl xanthate using Fe2O3/TiO2/Flyash nanophotocatalyst using Taguchi statistical approach

Xanthate from mineral processing wastewater is a major threat to the ecosystem. Photocatalysis is emerging as the most effective process with the invention of new nanophotocatalytic materials. The present research focuses on developing the ternary nanocomposite Fe2O3/TiO2/Flyash by a facile hydrothermal method combined with a water bath precipitation method for the efficient degradation of potassium ethyl xanthate (KEX). Taguchi’s experimentation (L16) orthogonal array is used for the optimization of process parameters to get maximum KEX degradation efficiency. The optimized parameters are found to be calcination temperature 400 OC, photocatalyst dosage 0.7 g/L, pH 5, pollutant concentration 10 mg/L, and light intensity 100 W. The percentage contribution of each parameter is obtained through the ANOVA statistical approach as calcination temperature > pH>pollutant concentration > photocatalyst dosage > light intensity. The adsorption mechanism follows the Freundlich isotherm and fits well with pseudo-first-order and second-order kinetics. Material characterization is also done to analyze the crystal structure and morphology of the newly developed nanocomposite to gain a better understanding of the mechanism. This study indicates that the newly developed nanocomposite photocatalyst can effectively degrade potassium ethyl xanthate under light irradiation for 60 min.

Metaheuristic optimization algorithms-based prediction modeling for titanium dioxide-Assisted photocatalytic degradation of air contaminants

Airborne contaminants pose significant environmental and health challenges. Titanium dioxide (TiO2) has emerged as a leading photocatalyst in the degradation of air contaminants compared to other photocatalysts due to its inherent inertness, cost-effectiveness, and photostability. To assess its effectiveness, laboratory examinations are frequently employed to measure the photocatalytic degradation rate of TiO2. However, this approach involves time-consuming requirements, labor-intensive tasks, and high costs. In literature, ensemble or standalone models are commonly used for assessing the performance of TiO2 photocatalytic degradation of water and air contaminants. Nonetheless, the application of metaheuristic hybrid models has the potential to be more effective in predictive accuracy and efficiency. Accordingly, this research utilized hybrid machine learning (ML) algorithms to estimate the photo-degradation rate constants of organic air pollutants using TiO2 nanoparticles and exposure to ultraviolet light. Six metaheuristics optimization algorithms, namely, nuclear reaction optimization (NRO), differential evolution algorithm (DEA), human felicity algorithm (HFA), lightning search algorithm (LSA), Harris hawks algorithm (HHA), and tunicate swarm algorithm (TSA) were combined with random forest (RF) technique to establish the hybrid models. A database of 200 data points was acquired from experimental studies for model training and testing. Furthermore, multiple statistical indicators and 10-fold cross-validation were employed to examine the established hybrid model's accuracy and robustness. The TSA-RF model demonstrated superior prediction accuracy among the six suggested models, achieving an impressive correlation (R) of 0.90 and a lower root mean square error (RMSE) of 0.25. In contrast, the HFA-RF, HHA-RF, and NRO-RF models exhibited a slightly lower R-value of 0.88, with RMSE scores of 0.32. The DEA-RF and LSA-RF models, while effective, showed a marginally lower R-value of 0.85, with RMSE values of 0.45 and 0.44, respectively. Moreover, the SHapley Additive exPlanation (SHAP) results indicated that the degradation rates of air contaminants through photocatalysis were most notably influenced by factors such as the reactor sizes, photocatalyst dosage, humidity, and intensity.

Precursor effect on the hydrothermal synthesis of pure ZnO nanostructures and enhanced photocatalytic performance for norfloxacin degradation

The indiscriminate production and use of antibiotics have caused an environmental imbalance. Therefore, advanced oxidative processes such as photocatalysis have been proposed to eliminate the presence of such emerging pollutants. On the other hand, the use of photocatalytic processes requires the development of highly efficient photocatalysts. This paper introduces photocatalysts based on ZnO nanostructures with different morphologies and grown by low-temperature hydrothermal synthesis. The choice of zinc precursor resulted in significant variations in both the morphology and size of the ZnO particles. Morphologies, such as, dumbbell-like structures, nanogranules, and ellipsoidal particles were obtained by altering the zinc precursor in a slightly alkaline medium, and parameters such as photocatalyst dosage, initial concentration of antibiotic Norfloxacin (NOR), and pH in photocatalysis were thoroughly investigated. The reactive species responsible for NOR degradation were photogenerated holes, superoxide radicals, and hydroxyl radicals, with the latter showing a greater contribution. Degradation pathways are also proposed, and intermediate products were identified by LC-MS. Thirteen degradation products, of which six were reported for the first time, were detected. Among the synthesized morphologies, nanogranules exhibited superior photocatalytic activity, achieving 100% NOR degradation after 70 min under UV-C light and excellent reusability after three cycles (97%). The results surpass those from previous studies, since the simple and efficient photocatalysts employed led to shorter degradation times.

Synergistic effect in ZIF-67/MoS2 entrenched MWCNT photo (electro) catalyst for degradation of tetracycline and alternative to Pt counter electrode in dye-sensitized solar cells

Photocatalytic water purification is an effective environmental protection approach for removing hazardous chemicals in water, besides solar energy conversion is a trustworthy and sustainable choice for the future due to rising energy demands. The present research focus is on synthesis of Metal-Organic Framework (MOF) based composite, Zeolitic Imidazolate Framework-67/Molybdenum Disulfide (ZIF-67/MoS2) entrenched Multi-Walled Carbon Nanotubes (MWCNT) as a catalyst for photodegradation of tetracycline (TC), as well as substitute for Pt counter electrode in Dye-Sensitized Solar Cell (DSSC). The crystalline structure, optical response, shape, porosity, quantum states, and chemical configuration were determined using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-DRS), Photoluminescence spectroscopy (PL), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET), and X-ray Photoelectron Spectroscopy (XPS), respectively. The degradation efficiency of ZIF-67/MoS2/MWCNT catalyst under effect of operational parameters namely, photocatalyst dosage, solution pH, coexisting ions, TC concentrations and irradiation time were studied consecutively. ZIF-67/MoS2/MWCNT composite achieved 96.1 % degradation efficiency of TC under white light irradiation. Interestingly, when utilized as a counter electrode in DSSCs, this composite-based electrode delivered the highest Power Conversion Efficiency (PCE) of 3.86 % with a short-circuit current density (JSC) of 7.54 mA cm−2 and open-circuit voltage (VOC) of 0.79 V. The observed enhancement is attributed to lesser peak-to-peak separation (EPP), lower electron lifetime, lower charge transfer resistance (RCT) and higher exchange current density (J0). Based on these findings, ZIF-67 inclusion in MoS2/MWCNT composite is not only an effective catalyst for water treatment but also a good catalyst for I3− reduction in DSSCs.

Development of simplistic and stable Co-doped ZnS nanocomposite towards excellent removal of bisphenol A from wastewater and hydrogen production: Evaluation of reaction parameters by response surface methodology

BackgroundEnvironmentally friendly and sustainable approaches for the removal of hazardous pollutants from wastewater continue to be explored. The present study presents the novel Co-ZnS nanocomposites which were synthesized by the ethanolic crude extract of Oxystelma esculentum and then successfully evaluated towards degradation of Bisphenol A and hydrogen production. The synthesized nanocomposites were systematically characterized by multiple state-of-the-art experimental techniques. MethodsThe present study illustrates the green synthesis of Co-doped ZnS nanocomposites and their promising potential for photodegradation of BPA and hydrogen production. The nanocomposite shows an excellent potential for BPA degradation (0.052 min−1) and hydrogen evolution (3157.9 µmolh−1 g−1). The detailed optimized analysis of synthesized nanocomposite demonstrates remarkable abilities to degrade organic pollutants by applying a “response surface methodology” model. Significant FindingsThe optimized value of the photocatalyst along with optimized parameters presented considerable photocatalytic activity for the degradation of BPA (94.69 %) and the value of hydrogen (3157.9 µmolh−1 g−1). Then, the confirmation of the results (theoretical and experimental yield) was carried out by RSM. The RSM indicated the predicted D % value of 96.84 % via the developed model with the optimized conditions of pH = 5.146, BPA dose = [53.448 mg/L], Photocatalyst dose = [58.3058 mg], and temperature = 32.2673 °C. The pHzpc of the prepared photocomposites was found to be ∼6.9.

Novel Fe2O3/Bi2O3/CeO2 heterojunction photocatalyst for wastewater treatment: Characterization, photocatalytic performance and mechanism study

A novel ternary Fe2O3/Bi2O3/CeO2 (FeB/CeO2) heterojunction nanocomposite with different Fe2O3/Bi2O3 amounts on CeO2 (5, 10, 20, 30 and 40 wt%) was synthesized through a simple wet impregnation process. The properties of the synthesized nanocomposite were validated thorough XPS, XRD, FE-SEM, TEM, and EDS-Mapping analyses. This photocatalyst exhibited exceptional efficiency in the of Tetracycline’s (TC) photodegradation in comparison to individual Fe2O3, Bi2O3, and CeO2. The effect of Fe2O3/Bi2O3 loading on CeO2 and the influence of operational factors on TC decomposition including photocatalyst dosage (0.05–0.2 g/L), TC concentration (10–40 mg/L), and pH (1–11) were examined with the optimal conditions yielding an experimental degradation efficiency of 99.35 %. Moreover, scavenger tests showed that O2− and OH radicals served as the main oxidative radical species. The study further delved into proposing potential degradation pathways of TC in accordance with liquid chromatography tandem-mass spectrometry analysis. Notably, the stability of the synthesized photocatalyst was assessed through five degradation cycles, affirming its sustained effectiveness.

Green biosynthesized N-doped CuO@Zeolite nanocomposite for the efficient photodegradation of toxic organic pollutants from wastewater

Nanotechnology is one of the most advanced methods available for the degradation of toxic pollutants from the environment. Specifically, nanoparticles generated with plant extracts are more stable and biocompatible than those produced using traditional chemical and physical processes. The current study focuses on the green synthesis of N-CuO@Zeolite nanocomposite with Camellia sinensis (green tea) leaf extract. The green synthesized nanocomposite was used for the photocatalytic degradation of hazardous organic pollutants, including Auramine-O (AO) and yellow color textile industrial dye (YD). Under direct sunlight irradiation, synthesized nanomaterials exhibited excellent photocatalytic activity for AO and YD degradation. The best conditions for photocatalytic degradation were found to be pollutant concentrations of 2 mg L−1 for AO and 6 mg L−1 for YD, photocatalyst dosages of 15 mg for both AO and YD, and neutral pH for both pollutants. Within 150 minutes, the synthesized N-CuO@zeolite nanocomposite attained degradation efficiencies of 95 % for AO and 92 % for YD, compared to its parent materials N-CuO (80 % for AO and 76 % for YD) and CuO (68 % for AO and 65 % for YD). The degradation rates of both pollutants were accurately described by first-order kinetics, consistent with the Langmuir adsorption model. Additionally, the ecologically sustainable novel N-CuO@Zeolite nanocomposite illustrated superior reliability and reusability, keeping photocatalytic efficiency even after ten cycles of constant utilization, and its long-term stability was confirmed by PXRD analysis after processing. The material's excellent reusability and stability emphasize the nanocomposite's potential as a long-term solution for industrial wastewater treatment applications.

Synthesis of g-C3N4 decorated with ZIF-8 and CuFe2O4 as a highly efficient and magnetically separable photocatalyst for degradation of tetracycline

In this study, for the first time a magnetically recoverable zeolitic imidazolate framework-8 (ZIF-8) / graphite carbon nitride (g-C3N4)/ cooper ferrite (CuFe2O4) nanocomposite was prepared through a fast and simple wet impregnation procedure. The magnetic behavior of the ZIF-8/g-C3N4/CuFe2O4 heterostructure was used for the easy recovery of the nanocomposite by an external magnet. After studying the structural, crystallinity, magnetic, and photophysical properties of the as-syntesized sample, its application was investigated for the enhanced photodegradation of tetracycline under visible light illumination. The band gap energies for ZIF-8, g-C3N4, and CuFe2O4 were obtained 5.1 eV, 2.8 eV, and 1.3 eV, respectively. After combination of ZIF-8, g-C3N4, and CuFe2O4, the band gap energy was obtained to 2.4 eV, which indicate the improvement of photocatalytic activity of ZIF-8/g-C3N4/CuFe2O4 nanocomposite. Among the as-synthesized photocatalyst samples, the ZIF-8/g-C3N4/CuFe2O4 showed an excellent photocatalytic activity (99.15 %) for degradation of tetracycline within 65 min irradiation of visible light, solution pH of 5 and photocatalyst dosage of 0.75 g/L. The rate constant of the ZIF-8/g-C3N4/CuFe2O4 is almost 13.1, 9.9, and 15.6 times higher than that of ZIF-8, g-C3N4, and CuFe2O4, respectively. The ZIF-8/g-C3N4/CuFe2O4 heterojunction showed the effective degradation activity for four consecutive cycles, which exhibited its excellent reusability and stability. Moreover, the free radical quenching tests confirmed that holes, and hydroxyl radicals were the main reaction species for degradation of tetracycline. Altogether the preparation of novel ZIF-8/g-C3N4/CuFe2O4 provides an promise avenue for the development of high potential magtenticaly photocatalytic systems for sustainable tetracycline production with remarkable efficiencies.

Novel Starch-Modified NiCrMn-LDH-Based Composite for Photocatalytic Degradation of Reactive Orange 13

Water pollution has become a great challenge today. To address this problem regarding wastewater treatment by removing toxic synthetic dyes from wastewater, this research focused on the synthesis of a novel starch-modified NiCrMn-layered double hydroxide composite through the coprecipitation method and applied it as a photocatalyst for the degradation of reactive orange 13 dye. The synthesized photocatalyst was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), point of zero charges (PZC), dynamic light scattering (DLS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Zeta potential techniques. These techniques revealed different characteristics of photocatalysts, like surface and structural properties. According to BET analysis, the final composite had 2.5 × 102 m2/g BET-specific surface area with a 45.56 nm pore radius value, and the overall composite found as mesoporous. Similarly, in DLS analysis, bare NiCrMn-LDH had 404 nm hydrodynamic size, which increased for the final starch composite up to 667 nm. Zeta potential value changed from −14.56 mV to 0.95 mV after the incorporation of starch with NiCrMn-LDH. They confirmed the incorporation of starch with trimetallic NiCrMn-layered double hydroxide (2:1:2). Starch association improved the properties of the photocatalyst like surface area. Different parameters like pH value, initial dye concentration, photocatalyst dose, hydrogen peroxide concentration, effect of sacrificial reagent, and effect of inorganic anions were studied for degradation of RO13. Overall, the photocatalysis process for RO13 followed pseudo-first-order kinetics. Photocatalytic degradation reactions for reactive orange 13 were conducted with an initial dye concentration of 10 mg/L, photocatalyst dosage of 20 mg/50 mL, and pH value at 3 in the presence of sunlight, resulting in an impressive degradation removal rate of 86.68%. This remarkable degradation ability of the photocatalyst for reactive orange 13 proves this composite was highly efficient.

Visible light responsive SiO2/g-C3N4/BiOBr/Bi heterojunction photocatalyst for degradation of rhodamine B

For the purpose of alleviating the negative influence of rhodamine B (RhB) abuse on the environment, it is imperative to design a green and efficient photocatalyst for tackling organic dye-contaminated wastewater. Herein, a novel SiO2/g-C3N4/BiOBr/Bi (denoted as Si/CN/BiOB/Bi) photocatalyst with enhanced photodegradation activity has been successfully created. The influence of variable parameters including Bi doping amount, initial concentration of RhB, photocatalyst dosage, and reaction temperature on the photocatalytic performance of Si/CN/BiOB/Bi under visible light illumination are analyzed in detail. Results indicated that the degradation rate constant of RhB over Si/CN/BiOB/Bi-0.5 is 25.1, 18.1, and 2.2 times higher than that of CN, Si/CN, and Si/CN/BiOB, respectively. The Si/CN/BiOB/Bi-0.5 photocatalyst displayed high photocatalytic performance after 5 recycled runs. The improved photocatalytic performance can be attributed to the novel morphology as well as the excellent synergetic effects of Si/CN, BiOBr, and Bi, which enables the catalysts to accelerate the separation of photogenerated carriers. In brief, a new Si/CN/BiOB/Bi photocatalyst has a great application perspective for the purification of RhB wastewater.

Dynamic Trio: CuWO4@C3N5/Polypyrrole nanocomposites Combat Chlorpyrifos and Rhodamine B in waste water

In this study, we investigate the photocatalytic degradation of chlorpyrifos pesticide (CPy) and Rh B dye using nanoparticles of C3N5 and CuWO4 dispersed within a PPy matrix. Using a variety of techniques, a composite called PPy@C3N5/CuWO4 was synthesised and thoroughly characterised. These techniques included XRD, SEM/EDS, TEM, BET, DRS, PL, and TOC. The combination displayed remarkable photoactivity and photostability in the degradation of CPy and RhB in aqueous solutions when exposed to visible light. The band gap values of C3N5, CuWO4, and C3N5@CuWO4 are (2.2, 2.0, and 1.9 eV), improved. Several factors were meticulously optimised and adjusted in order to investigate the process of photocatalytic degradation. These factors included pH levels, initial solution concentration, irradiation time, and the amount of photocatalyst used. An optimal photodegradation efficiency of approximately 92.5 % was attained by utilising a CPy and Rh B concentration of 5 mg/L, maintaining a pH of 3.5, and employing a photocatalyst dosage of 0.5 g/L. The photocatalyst was also tested for its ability to regenerate and be recycled four times, which showed that it was relatively stable.