Conditions For Photocatalytic Degradation Research Articles

Preparation of Soybean Dreg-Based Biochar@TiO2 Composites and the Photocatalytic Degradation of Aflatoxin B1 Exposed to Simulated Sunlight Irradiation.

Aflatoxin B1 (AFB1) is a highly toxic carcinogen severely harmful to humans and animals. This study fabricated SDB-6-K-9@TiO2 composites via the hydrothermal synthesis method to reduce AFB1. The structural characterization results of the photocatalytic composites showed that TiO2 was successfully loaded onto SDB-6-K-9. The different photocatalytic degradation conditions, photocatalyst kinetics, recycling performance, and photocatalytic degradation mechanism were investigated. Photocatalysis with 6 mg of 4%SDB-6-K-9@TiO2 in a 100 μg/mL AFB1 solution presented a reduction of over 95%, exhibiting excellent performance, high stability, and reusability even after five cycles of photocatalytic experiments. Active species trapping experiments confirmed that holes (h+) played the most critical role. After structural analysis and identification of the photocatalytic degradation products, the photodegradation path and photocatalytic oxidation mechanism of 4%SDB-6-K-9@TiO2 were postulated. The results show a new way to improve TiO2's photocatalytic performance, providing a certain theoretical basis for the effective AFB1 reduction.

Photocatalytic degradation of methylene blue under visible light using carbon-doped titanium dioxide as photocatalyst

A visible light-active photocatalyst, carbon-doped titanium dioxide (C-doped TiO2) with an anatase phase, was synthesized using a simple and cost-effective method, with glucose serving as the carbon source for doping. The surface morphology, crystal structure and elemental composition of the catalyst was analyzed by SEM, XRD and EDX respectively. Raman spectroscopic and XRD analysis showed the consistency of the anatase phase throughout the preparation process. FT-IR, TGA, and EDX depicted the purity of the prepared catalyst. SEM images revealed that the average particle size of the catalyst is approximately 178 nm, which is smaller than that of pure TiO2. Finally, as a proof-of-concept photocatalytic activity of the catalyst was investigated on a typical organic dye, methylene blue, under two different light sources (UV light and visible light) by varying the catalyst amount, the concentration of dye, and pH of the degrading medium. Results showed that the prepared C-doped TiO2 shows a promising result under the visible light irradiation which seems limited in case of pure TiO2. The optimum photocatalytic degradation conditions are pH 3, catalyst dosage 0.15 g, and dye concentration 3 × 10−5 M. At optimum conditions visible light shows 53 % degradation and UV light degrades almost all the dye molecules. The enhanced photocatalytic activity of C-doped TiO2 in visible light is due to carbon doping, which reduces the bandgap energy and enables the absorption of visible light photons. This convenient technique can be a great solution for the removal of dyeing wastes economically using low-cost visible light or sunlight and large scale production for industrial application.

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.

Design of solar-light-driven agglomerated cluster-like transition/rare-earth metal oxide-supported carbon-based nanomaterial for the degradation of azo dye

Transition and rare-earth metal oxide-supported nanomaterials have ignited an attraction in many fields such as energy, environment and etc. In this work, transition/rare-earth metal oxide-supported carbon-based nanomaterials (TRM) were prepared by hydrothermal method and it was characterized by UV-DRS, FTIR, XRD, AFM, FE-SEM, HR-TEM, and EDAX techniques. Doping levels of transition/rare-earth metal oxides on the carbon-based material impacts the photocatalytic degradation efficiency. The photocatalytic activity (PCA) of the prepared TRM was examined, and the highest degradation percentage was observed compared to other reported catalysts. TRM 2 exhibits the maximum degradation percentages of azo dye under sunlight (99.8 %) irradiation. The optimization studies were conducted, such as the effect of pH, catalyst dosage, and concentration. The optimum condition for photocatalytic degradation was pH - 6.51, TRM dosage - 10 mg, and dye concentration - 5 ppm. The kinetic studies were conducted for the various concentrations (5–20 ppm), and the rate of reaction was determined; it clearly illustrated that the reaction follows a pseudo-first-order kinetics. The enhanced PCA in the TRM 2 was due to the combination of transition/rare-earth metal oxides on the carbon-based material. This transition/rare-earth metal oxide-supported carbon-based nanomaterials (TRM) is practically helpful in degrading environmental pollutants in real-time wastewater under sunlight irradiation.

G-C3N4/graphene oxide/SnFe2O4 ternary composite for the effective sunlight-driven photocatalytic degradation of methylene blue.

A broadly used dye, methylene blue (MB), adversely impacts human health and water resources, which triggers efficient methods for its elimination. Semiconductor-based heterogeneous photocatalysis is an environmentally friendly approach that effectively degrades organic pollutants. The purpose of the current work is to elucidate and validate the application of a promising g-C3N4/GO/SnFe2O4 (CGS) composite for the environmental remediation of methylene blue dye. The ternary CGS composite has been synthesized using a solvothermal approach. The fabricated composites were analyzed through FTIR, XRD, SEM/EDX, UV-VIS spectroscopy, TEM, and XPS. The photoactivity of composites and affecting parameters (pH, H2O2 dosage, composite amount, initial dye concentration, and irradiation time) were observed in sunlight illumination. The optimal conditions for photocatalytic degradation were pH = 5, photocatalyst dosage = 30 mg/100 mL, H2O2 dosage = 6 mM, and initial dye concentration (IDC) of 10 ppm employing ternary CGS composite, and MB dye was degraded effectively within 1 h. Ninety-eight percent degradation efficacy was attained by employing ternary CGS composite under the optimized conditions. Scavenging analysis suggested that •OH radicals were the key reactive oxygen species (ROS) responsible for the photodegradation of MB dye. Furthermore, the CGS nanocomposite exhibited outstanding recyclability of 84% after five consecutive runs, demonstrating its potential for use in practical applications, particularly pollutant removal.

Synthesis of NiFe2O4/SiO2/NiO Magnetic and Application for the Photocatalytic Degradation of Methyl Orange Dye under UV Irradiation

NiFe2O4/SiO2/NiO magnetic was successfully synthesized using NiFe2O4, SiO2, and NiO as the core, interlayer, and shell, respectively. NiFe2O4/SiO2/NiO under UV light irradiation was used for photocatalytic degradation of methyl orange dye with different pH, catalyst dose, and initial dye concentration. This composite was characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), Scanning Electron Microscopy-Electron Dispersive X-ray Spectroscopy (SEM-EDs), Vibrating Sample Magnetometer (VSM), UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS), and Point of Zero Charge (pHpzc). The results showed that the composite is a superparamagnetic material with a saturation magnetization value of 44.13 emu/g. It also has a band gap of 2.67 eV with a pHpzc of 6.33. The optimum conditions for photocatalytic degradation were at pH of 4; 0.50 g/L catalyst dose, and 10 mg/L initial concentration. NiFe2O4/SiO2/NiO degradation efficiency to methyl orange dye was 95.76%. The photocatalytic degradation in different concentrations follows the pseudo-first-order, where the greater the concentration, the smaller the constant rate (k). After five cycles of repeated usage, NiFe2O4/SiO2/NiO has good catalytic performance as well as efficient and favourable of a recyclable photocatalyst. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Statistical optimization of process conditions for photocatalytic degradation of phenol with bismuth molybdate photocatalyst

Statistical optimization of process conditions for photocatalytic degradation of phenol with bismuth molybdate photocatalyst

Photocatalytic degradation of Congo red dye using Fe-doped TiO2 nanocatalysts

Fe-doped TiO2 (2, 5, 10, 15 and 20% wt. of Fe) photocatalysts have been synthesized by sol-gel method using titanium aquacomplex precursor. The structure and morphology have been characterized by XRD, BET, SEM, and EDS analyses, Mossbauer and IR spectroscopies. XRD analysis confirmed the anatase structure. The introduction of ferric ions into the titania structure causes its amorphization. The crystallite sizes of obtained samples are around 3 nm. Fe-doped TiO2 samples possess mesoporous structure and high specific surface area (from 274 m2g-1 for 5Fe-TiO2 to 416.4 m2g-1 for 20Fe-TiO2). Mossbauer spectroscopy data confirms the incorporation of Fe3+ ions in the anatase structure. Photocatalytic degradation of Congo red dye using Fe-doped TiO2 photocatalysts was studied under the UV-A light. Optimized conditions for photocatalytic degradation of CR in the presence of hydrogen peroxide are obtained. It was found that the 2Fe-TiO2 sample in the presence of 20 mM H2O2 solution showed highest efficiency in dye photodegradation (99.4%) under UV-A light. The photodegradation kinetics was analyzed using a smartphone and fits well with first-order kinetics model.

Application in photocatalytic degradation of zearalenone based on graphitic carbon nitride

AbstractA semiconductor nano‐material was prepared, and its degradation efficiency of zearalenone (ZEN) was studied. The photocatalytic material graphitic carbon nitride (g‐C3N4) was synthesized by the traditional method of hot cracking. Its structure was characterized by X‐ray diffraction (XRD), Fourier‐transform infrared (FTIR), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic degradation experiment showed that under the irradiation of ultraviolet (UV) lamp (254 nm, including 185 nm), g‐C3N4 could induce photocatalytic effect, which provided a new method for the degradation of ZEN in real powder samples. The experimental conditions of photocatalytic degradation of the primary reference material of ZEN and ZEN in real powder samples were explored. And the degradation products of ZEN were analyzed after high‐performance liquid chromatography–mass spectrometry (HPLC–MS). Under each optimal experimental conditions, the degradation rate on primary reference material of ZEN and ZEN in real powder samples was 96.0% and 50.0%, respectively. The results in this work provide a theoretical reference and practical basis for the photocatalytic degradation of mycotoxin in real powder samples by g‐C3N4.

Polyaniline Supported Ag-Doped ZnO Nanocomposite: Synthesis, Characterization, and Kinetics Study for Photocatalytic Degradation of Malachite Green

Ag-ZnO/PANI nanocomposite was prepared via the sol-gel technique following in situ oxidative polymerization of polyaniline (PANI). XRD, UV-Vis, and FT-IR spectroscopy were employed to study the crystal size, bandgap energy, and bond structure of as-synthesized nanocomposites. The mean crystallite size of the nanocomposite determined from XRD was 35.68 nm. Photocatalytic degradation of malachite green (MG) dye using as-synthesized photocatalysts was studied under visible light irradiation. The highest degradation efficiency was recorded for Ag-ZnO/PANI nanocomposites (98.58%) than Ag-ZnO nanoparticles (88.23%) in 120 min. The kinetics of photocatalytic degradation of MG follows pseudo-first-order reaction with rate order of 1.16 10−2 min−1. Moreover, the photocatalytic activity of Ag-ZnO/PANI nanocomposites was evaluated and compared with Ce-Cd oxide, electrospun P(3HB)-TiO2, and with other catalysts in the literature. The optimal conditions for photocatalytic degradation are as follows: the concentration of malachite green (0.2 g/l), pH (8), and the concentration of catalyst load (0.2 g/l) under visible light with an irradiation time of 120 min.

Optimization of photocatalytic degradation conditions and toxicity assessment of norfloxacin under visible light by new lamellar structure magnetic ZnO/g-C3N4

Degradation of norfloxacin (NFX) by zinc oxide (ZnO)/g-C3N4, a magnetic sheet ZnO with g-C3N4 on its surface was studied. Through a new preparation system method, hydrothermal reaction provides a solid-layered magnetic ZnO material basis, and the simple thermal condensation method was used to transform the urea into g-C3N4 on the magnetic sheet ZnO in a uniform and orderly manner to increase the stability and photocatalytic performance of the material. Compared with previous studies, the pore volume and photocatalytic performance of the material are improved, and became more stable. By studying the degradation effect of basic and photocatalytic materials prepared in different proportions, the kinetic constant of ZGF is 0.01446 (min−1). The response surface methodology (RSM) was used to study the optimization and effect of solution pH (4−12), photocatalyst concentration (0.2–1.8 g/L), and NFX concentration (3–15 mg/L) on the degradation rate of NFX during photocatalytic degradation. The R2 value of the RSM model was 0.9656. The NFX removal rate is higher than 90% when the amount of catalyst is 1.43 g/L, the solution pH is 7.12, and the NFX concentration is less than 8.61 mg/L. After 5 cycles, the degradation rate of magnetic materials decreased to 92.8% of the first time. The capture experiment showed that the photocatalytic machine Toxicities was mainly hole action. The TOC removal rate within 2 h was 30%, a special intermediate toxicity analysis method was adopted according to the characteristics of NFX's inhibitory effect on Escherichia coli community. The toxicity of degraded NFX solution disappeared, and the possibility of non-toxic harm of by-products was verified. LC-Q-TOF method was used to detect and analyze various intermediate products converted from NFX after photocatalytic degradation, and the photocatalytic degradation pathway of NFX was proposed.

Coal fly ash-based copper ferrite nanocomposites as potential heterogeneous photocatalysts for wastewater remediation

Coal fly ash (CFA) based-copper ferrite nanocomposites were fabricated, characterized, and applied for the photocatalytic degradation of Methyl Orange (MO) dye. The hydrothermal synthesis route was opted for the fabrication of pristine copper ferrite nanoparticles and its CFA nanocomposites. The prepared photocatalysts were analyzed in terms of structural, surface morphology, chemical state analysis, elemental composition, and optical response. The photocatalytic activity of nanocomposites was investigated sequentially under ultraviolet light (254 nm) and influencing parameters (pH, H2O2 dose, photocatalyst content, dye initial concentration, irradiation time) were studied. The optimized conditions for photocatalytic degradation were found at pH = 5, composite dose = 100 mg/L, H2O2 = 10 mM using CFA nanocomposite and the dye was efficiently degraded within 60 min. The best degradation efficiency of ~98% was achieved using CFA-CuFe2O4 (1:1) under the optimized conditions. The key reactive species (OH, h+, and e−) for photocatalytic degradation were determined by a radical scavenging experiment and OH radicals were found to be the most effective ones. The kinetic study of Fenton oxidation processes was conducted using Behnajady-Modirshahla-Ghanbery (BMG) kinetic model. Response surface methodology was the statistical tool for the assessment of interaction effect among experimental variables.

Photocatalytic Degradation of Synthetic Sulfur Pollutants in Petroleum Fractions under Different pH and Photocatalyst

Thiophene is one of the sulfur compounds in the petroleum fraction that can be harmful to living things and lead to a critical effect on the ecosystem. Photocatalytic degradation is one of the promising methods in treating wastewater as it can mineralization of pollutants into carbon dioxide and water. Other than that, this method is non-toxic and relatively low cost. The production of hydroxyl radicals playing a vital role in the degradation of organic pollutants. It has been claimed that the usage of zinc oxide (ZnO) nanoparticles could give an excellent degradation process as this photocatalyst have high photosensitivity, low cost and chemically stable. However, the preparation method of ZnO nanoparticles will affect the agglomeration, particle size, shape and morphology of particles and lead to influence the photocatalytic activity in degrading thiophene. Therefore, this study focused on the effectiveness of ZnO nanoparticles in the presence of fibrous nanosilica (KCC-1) and polyethylene glycol (PEG) as the capping agent to degrade synthetic thiophene. ZnO/KCC-1 had been synthesized via the precipitation method and characterized by using Fourier Transform Infrared (FTIR). The chemical bond and nature of the photocatalyst from the FTIR results proved that the synthesis process to produce the ZnO/KCC-1 was succeed. The large surface area of KCC-1 increases the effectiveness of ZnO which is supported by the experimental data. Accordingly, the optimum condition for photocatalytic degradation of thiophene is under pH 7 by using ZnO/KCC-1 as photocatalyst. Hence, it is believed that this research could be implemented to remove the thiophene in petroleum fraction from the actual industrial effluents and this can preserve nature in the future.

Efficient photocatalytic degradation of Malachite green dye using facilely synthesized cobalt oxide nanomaterials using citric acid and oleic acid

Citric acid and oleic acid modified cobalt oxide nanomaterials successfully fabricated by sol-gel process and used to remove malachite green (MG) by photocatalytic degradation. The synthesized nanomaterials were characterized by powder X-ray diffraction (P-XRD), Scanning electronic microscopy (SEM), Transmission electron microscopy (TEM), UV–Visible spectrophotometer, Fourier transform infrared spectroscopy (FT-IR) and Thermogravimetric Analysis (TGA) in order to investigate their structural, morphological, optical, functional and thermal properties, respectively. The PXRD gave the crystalline nature with average crystallite size of 29 and 42 nm for citric acid and oleic acid modified cobalt oxide nanomaterials, respectively. SEM images indicate layered porous aggregates morphology having higher porosity. Optimum condition for photocatalytic degradation of MG dye were found at pH 6.84, dose 0.5 gL-1 for 1 × 10−5 M concentrated dye. Citric acid modified cobalt oxide catalyst exhibited 91.2% photocatalytic degradation of MG dye while in oleic acid modified sample exhibited 66.6% under simulated light due to greater chelating power of citric acid as compare to oleic acid. Kinetics results for MG dye degradation follow to pseudo-second-order kinetics with rate constants 0.00653, 0.084 and 0.00633 mol−1L1min−1 for CoCA, CoOA and Co NPs, respectively. In addition, possible mechanism for the photodegradation of MG dye is also proposed.

WO3 nanoplates decorated with polyaniline and CdS nanoparticles as a new photocatalyst for degradation of imidacloprid pesticide from water.

This study focused on the photocatalytic degradation of imidacloprid (IM) in water as the model pesticides. The effective division of photogenerated charge carriers is important in the photocatalytic reactions. So, a new PANI/WO3-CdS photocatalyst was synthesized by a simple method. The prepared PANI/WO3-CdS nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy compatible with energy dispersive spectroscopy (FESEM-EDS), and X-ray diffraction (XRD). Degradation of IM pesticide under visible light irradiation was carried out to investigate the photocatalytic efficiency of the prepared nanocomposite. The effect of operational parameters on the degradation performance of pesticides was studied by response surface methodology (RSM). The optimum conditions for photocatalytic degradation of IM (94.7%) were found to be 10 ppm of IM, 150 mg of PANI/WO3-CdS, and pH = 3.0. The apparent rate constant of IM photodegradation over PANI/WO3-CdS was 0.016 min-1. According to results, PANI/WO3-CdS can serve as an efficient, and recyclable photocatalyst for imidacloprid degradation in an aqueous media.

Construction of 1T-MoS2 quantum dots-interspersed (Bi1-x Fe x )VO4 heterostructures for electron transport and photocatalytic properties.

The present study reports trigonal phase molybdenum disulfide quantum dots (MoS2/QDs)-decorated (Bi1−xFex)VO4 composite heterostructures. Initially, (Bi1−xFex)VO4 heterostructure nanophotocatalysts were synthesized through the hydrothermal method decorated with 1T-MoS2via a sonication process. 1T-MoS2@(Bi1−xFex)VO4 heterostructures were characterized in detail for phase purity and crystallinity using XRD and Raman spectroscopy. The Raman mode evaluation indicated monoclinic, mixed monoclinic-tetragonal and tetragonal structure development with increasing Fe concentration. For physiochemical properties, SEM, EDX, XPS, PL, EPR, UV-visible and BET techniques were applied. The optical energy band gaps of 1T-MoS2@(Bi1−xFex)VO4 heterostructures were calculated using the Tauc plot method. It shows a blue shift initially within a monoclinic structure then a red shift with an increase of Fe concentration. 1T-MoS2@(Bi40Fe60)VO4 with 2 wt% of 1T-MoS2-QDs carrying a mixed phase exhibited higher photocatalytic activity. The enhanced photocatalytic activity is attributed to the higher electron transportation from (Bi1−xFex)VO4 surface onto 1T-MoS2 surface, consequently blocking the fast electron–hole recombination within (Bi1−xFex)VO4. 1T-MoS2 co-catalyst interaction with (Bi1−xFex)VO4 enhanced the light absorption in the visible region. The close contact of small 1T-MoS2-QDs with (Bi1−xFex)VO4 develops a high degree of crystallinity, with fewer defects showing mesoporous/nanoporous structures within the heterostructures which allows more active sites. Herein, the mechanism involved in the synthesis of heterostructures and optimum conditions for photocatalytic degradation of crystal violet dye are explored and discussed thoroughly.

Tetracycline catalytic photodegradation with mesoporous phosphated TiO2: characterization, process optimization and degradation pathway.

Concern about the effect of tetracycline (TC) on the ecosystem has been increasing due to its endurance and low decomposition. Photocatalysts have attracted extensive interest as alternatives to other ordinary wastewater treatment methods. A nanosized mesoporous phosphated TiO2 (P-TiO2) photocatalyst was fabricated to degrade TC under Xe lamp irradiation. The TC degradation and COD removal rate reached 98.97% and 79.16% within 30 min. Photocatalysts were characterized by SEM, HRTEM, BET, DRS, XRD, XPS and FT-IR techniques. 31 experiments were designed to identify the best conditions for photocatalytic degradation of TC by response surface methodology (RSM) based on a central composite design (CCD). 6 key operating parameters were selected to study their interrelationships by CCD design. Based on the experimental data and ANOVA, the coefficient of determination (R2), the values of “Prob > F” and F-value were determined to be 0.9692, 0.002 and 7.87, respectively, which demonstrated that the model is significant. And the excellent correlation between the predicted and actual values also provided good confidence in the model. To achieve a higher removal rate of TC under appropriate and more economical experimental conditions, the optimum values of P-loading on TiO2, concentration of P-TiO2, irradiation time, photo intensity, pH and concentration of TC should be set to 17.45 wt%, 1.00 g L−1, 40.39 min, 5 A, 7, 29.93 mg L−1, respectively, in which the degradation of TC can reach 99.16%. Furthermore, the intermediates of TC verified by GC-MS analysis were mainly chains and rings. A possible pathway of photodegradation was also proposed.

Photocatalytic degradation of palm oil mill secondary effluent in presence of zinc oxide nanoparticles

Based on the previous research, it has been revealed that zinc oxide nanoparticles in presence of polyethylene glycol (ZnO-PEG) have high potential for photocatalytic degradation of industrial dye wastewater. However, the study on the performance of ZnO-PEG and ZnO−CC nanoparticles to treat palm oil mill secondary effluent (POMSE) is still limited. In addition, the optimum condition for photocatalytic degradation of POMSE in presence of ZnO-PEG and ZnO−CC nanoparticles under two different power of light source which are 18 W and 500 W also not been well discovered. The aim of this study was to observe the photocatalytic degradation efficiency through percentage of color reduction for POMSE after being treated. Based on this study, the best photocatalyst and the optimum condition for photocatalytic degradation of POMSE had been identified under 18 W of UV irradiation in the presence of 0.5 g/L of ZnO-PEG nanoparticles. While for the optimum condition, it had been found that the reduction percentage of color removal (70.75 %), turbidity (87.33 %), COD (68.31 %), BOD (650.1 mg/L) were obtained. Thus, it is believed that this research will attract much attention from researchers globally, as the benefits of an environmental approach has always been in the forefront of sustainable development.

Synthesis and Application of Fe-Doped TiO2 Nanoparticles for Photodegradation of 2,4-D from Aqueous Solution

2,4-Dichlorophenoxyacetic (2,4-D) is a toxic herbicide used to control weeds in agricultural sector. However, its residuals in soil and water are harmful for human and aquatic life. Therefore, the aim of this study was to evaluate the photocatalytic degradation of 2,4-D from aqueous solution using the Fe-doped TiO2 nanoparticles in the presence of UV and sunlight irradiation. The nanoparticles were synthesized via a mild hydrothermal process. The characteristics of the synthesized nanoparticles were determined using powder X-ray diffraction, Fourier transform infrared and scanning electron microscopy techniques. The effects of different parameters, including pH, nanoparticle dosage, initial 2,4-D concentration and dopant percentage on the degradation of 2,4-D, were investigated. The results demonstrated that the successfully doped nanoparticles had likely pseudo-spherical morphology. The optimum conditions for photocatalytic degradation of 2,4-D obtained at pH 7, nanoparticle dosage = 0.4 g/l, initial 2,4-D concentration = 10 mg/l, dopant percentage = 1.5% and contact time = 120 min. Under the optimal conditions, the photocatalytic degradation efficiencies of 2,4-D under UV and sunlight irradiation were 65 and 72%, respectively. In addition, the findings showed that 2,4-D degradation efficiency increased with increasing dosage of nanoparticles, while it decreased with increasing initial concentration of 2,4-D and initial pH. Therefore, the Fe-doped TiO2 nanoparticles could be used for the photodegradation of 2,4-D, and it is recommended for the degradation of other organic pollutants from aqueous media especially in tropical areas where a free energy source, i.e., sunlight, is available.

Selective synthesis of visible light active γ-bismuth molybdate nanoparticles for efficient photocatalytic degradation of methylene blue, reduction of 4-nitrophenol, and antimicrobial activity.

In this study, we have reported selective synthesis of bismuth molybdate (γ-Bi2M2O6) nanoparticles (NPs) under different pH conditions for photocatalytic degradation of methylene blue (MB), reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) and antimicrobial activities. The synthesis of pure phase γ-Bi2M2O6 at pH = 3 was confirmed by X-ray diffraction (XRD) and Raman analysis. A single hexagonal morphology was obtained at pH = 3 which shows the formation of the pure phase γ-Bi2M2O6 NPs. The mixed morphologies (hexagonal and spherical) were observed at different pH values other than pH = 3. The bandgap energy of all the synthesized Bi2M2O6 NPs is found in the visible region (2.48–2.59 eV). The photocatalytic activity of bismuth molybdate (BM) NPs was examined by the degradation of MB under visible light irradiation. Results show that 95.44% degradation efficiency was achieved by pure γ-Bi2M2O6 NPs compared to mixed phases (γ-Bi2M2O6, α-Bi2M2O6 and β-Bi2M2O6) synthesized at pH = 1.5 and 5. Moreover, the degradation efficiency of γ-Bi2M2O6 was enhanced to 98.89% by the addition of H2O2. The effective catalytic activity of γ-Bi2M2O6 was observed during the reduction of 4-NP to 4-AP by NaBH4. Potential antibacterial and antifungal activity of γ-Bi2M2O6 was observed, which gives a basis for further study in the development of antibiotics.