Search

High pesticide concentrations enter water sources following agricultural uses, increasing concerns about environmental safety and human health. The application of photoactive nanostructures has demonstrated promise as systems for pollutant degradation and water treatment. This work studied the synthesis of S-doped Ni–Co layered double hydroxides (S-doped Ni–Co LDHs) decorated with Fe3O4 nanoparticles. The XRD, FESEM-EDX, and TEM techniques were applied for the characterization of the S-doped Ni–Co LDH/Fe3O4 nanocomposite. The photocatalytic activity of the as-prepared photocatalyst was investigated for the degradation of the chlorpyrifos pesticide from aqueous solution under visible light irradiation. The effective parameters of photocatalytic degradation such as chlorpyrifos concentration, photocatalyst amount, and pH were investigated by the experimental design method. The synthesized photocatalyst revealed that the photocatalytic degradation performance of pesticides could reach 92.5% in 150 min under the optimum conditions. The high degradation efficiencies obtained demonstrated the effectiveness of this method and its potential for feasible application. [ABSTRACT FROM AUTHOR]

Triclosan is broadly utilized as preservative or antiseptic in various cosmetic and personal care products. It becomes hazardous for environmental safety and human health more than a certain concentration. In this research, graphene oxide (GO) nanosheets were prepared by composing Fe3O4@Au nanostructure decorated GO together with polypyrrole (PPy) (Fe3O4@Au‐PPy/GO nanocomposite) in a facile way. The composite excellent increased the electrochemical response, presenting a high sensitive electrochemical method for triclosan detection. The synthesized Fe3O4@Au‐PPy/GO nanocomposite was characterized for its morphological, magnetically and structural properties by FESEM‐mapping, TEM, and XRD. The Fe3O4@Au‐PPy/GO nanocomposites modified glassy carbon electrodes (GCE), Fe3O4@Au‐PPy/GO GCE, showed a higher sensitivity good stability, reproducibility, lower LOD (2.5×10−9 M) and potential practical application in electrochemical detection of triclosan under optimized experimental conditions. [ABSTRACT FROM AUTHOR]

A new electrochemical sensor based on Fe3O4@SiO2‐PANI‐Au nanocomposite was fabricated for modification of glassy carbon electrode (Fe3O4@SiO2‐PANI‐Au GCE). The Fe3O4@SiO2‐PANI‐Au nanocomposite was characterized by TEM, FESEM‐EDS‐Mapping, XRD, and TGA methods. The Fe3O4@SiO2‐PANI‐Au GC electrode exhibited an acceptable sensitivity, fast electrochemical response, and good selectivity for determination of quercetin. Under optimal conditions, the linear range for quercetin concentrations using this sensor was 1.0×10−8 to 1.5×10−5 mol L−1, and the limit of detection was 3.8×10−9 mol L−1. The results illustrated that the offered sensor could be a possible alternative for the measurement of quercetin in food samples and biological fluids. [ABSTRACT FROM AUTHOR]

In this research, a novel KIT‐5/Bi2S3‐Fe3O4 nanocomposite was prepared. The structure and morphology properties of the nanocomposite were well characterized by XRD, FESEM‐EDS‐mapping, TEM, and N2 adsorption–desorption. Benefiting from the visible light, the as‐prepared KIT‐5/Bi2S3‐Fe3O4 nanocomposite exhibit significantly improved photocatalytic performance for the degradation of parathion. The optimum photocatalytic efficiency of KIT‐5/Bi2S3‐Fe3O4 nanocomposite was investigated with the central composite design using Design Expert software. The four critical variables affecting parathion degradation such as the concentration of parathion, pH, irradiation time, and amount of KIT‐5/Bi2S3‐Fe3O4 nanocatalyst. A polynomial function corresponding to degradation percent was obtained for the experimental data. The results showed that this catalyst has a good performance for the degradation of parathion. [ABSTRACT FROM AUTHOR]

In the present research, Fe3O4 and WS2 nanoparticles immobilized on or in KIT‐6 (KIT: Korea Institute of Science and Technology) pores (KIT‐6/WS2‐Fe3O4) were synthesized and studied as a photocatalyst for degradation of representative chlorpyrifos as an organophosphorus pesticide. In addition, the KIT‐6/WS2‐Fe3O4 photocatalyst was characterized by different methods such as TEM, FESEM‐EDS‐Mapping, XRD, and N2 adsorption/desorption surface area, in order to understand their morphology, structural, and physical properties. The photocatalytic performance of this photocatalyst was investigated for degradation of chlorpyrifos by visible light irritation. The effects of variables such as chlorpyrifos concentration, KIT‐6/WS2‐Fe3O4 nanocatalyst amount, pH, and irradiation time on chlorpyrifos degradation efficiency was studied by central composite design with response surface methodology. The optimum conditions for CP degradation were obtained by 50 mg KIT‐6/WS2‐Fe3O4 nanocatalyst, and 7.2 ppm chlorpyrifos solution with pH = 6, at 52 min. The pseudo‐first‐order model with rate constants equal to 0.069 min−1 as best choice efficiency described the chlorpyrifos degradation process according to Langmuir‐Hinshelwood kinetic. [ABSTRACT FROM AUTHOR]

In this work, the photocatalytic activity of the synthesized graphene oxide (GO)‐Fe3O4/TiO2 mesoporous photocatalysts was evaluated using chlorpyrifos (CP) as a contaminant. The nano‐photocatalyst was characterized by X‐ray diffraction, field emission scanning electron microscopy with energy‐dispersive X‐ray spectroscopy, transmission electron microscopy, and specific surface area by the Brunauer–Emmett–Teller method. Using visible light, the GO‐Fe3O4/TiO2 mesoporous photocatalyst was investigated on the degradation of CP pesticide. The GO‐Fe3O4/TiO2 photocatalyst displayed a good photocatalytic activity, which was achieving 97% of CP degradation after 60 min. Finally, experiments were performed to evaluate GO‐Fe3O4/TiO2 mesoporous nanocatalyst activity on repeated applications; after several uses, its photocatalytic activity was retained, which indicated stability. [ABSTRACT FROM AUTHOR]

Chlorpyrifos (CP) is an organophosphorus pesticide used to control pests in agriculture. Brilliant green (BG) is a cationic dye widely used in textile and dyeing industry. However, the presence of pollutants in the aquatic environment has harmful effects on the environment and humans. Photocatalytic degradation can be appropriate method for water purification. Therefore, the Fe 3 O 4 /CdS-ZnS magnetic nanocomposite was synthesized and characterized by Brunauer-Emmett-Teller (BET) surface area analysis, Energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), UV-Vis-diffuse reflectance spectroscopy (DRS), and field emission scanning electron microscopy (FESEM) analyses and was used to degrade pollutants such as chlorpyrifos pesticide and brilliant green dye under visible light with source 300 W. Parameters that may be effective on photocatalytic degradation include pH, photocatalyst amount, contaminant concentration, photocatalyst and contaminant contact temperature and duration, light intensity as well as distance of light source from the reaction vessel. In the present study, the parameters that have the most influence on the degradation process were experimentally optimized, including pH, photocatalyst amount, photocatalyst reuse, and initial concentration. The study of the photocatalytic degradation rate of chlorpyrifos and brilliant green in optimal conditions (pH = 7, the concentration of pollutants = 10 ppm, volume of pollutants = 5 mL, and photocatalyst amounts for CP and BG were 0.0100 and 0.0015 g respectively) was obtained by Langmuir-Hinshelwood model. According to this model, the k app value for CP and BG were respectively 0.0315 and 0.0119 min -1 respectively. It has been concluded that the composition of CdS and ZnS caused inhibition of the recombination of photogenerated charge carriers, leading to high catalytic efficiency. Based on the results, the synthesized nanocatalyst showed that it has the ability to photocatalytic degradation of chlorpyrifos and brilliant green in aqueous solutions., (Copyright © 2019 Elsevier Inc. All rights reserved.)