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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.)

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]

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. [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]

Agricultural pesticides are known as the most important causes of water pollution due to their high environmental stability and production of carcinogenic products. Chlorpyrifos is broadly utilized to control pests in agricultural, residential, and commercial applications. The release of chlorpyrifos into water and wastewater sources may affect human health because of its chronic toxicity to aquatic organisms. Therefore, its degradation seems necessary. The present study aimed to investigate the photocatalytic efficiency of biochar nanocomposite based on grapefruit skin modified with Fe 3 O 4 and CdS nanoparticles (biochar/CdS-Fe 3 O 4) in the degradation of chlorpyrifos pesticide as an agricultural contaminant. The synthesized nanocomposites were characterized using field emission scanning electron microscopy (FESEM) with energy dispersive X-Ray spectroscopy (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The synthesized nanocomposite showed excellent photocatalytic performance due to the improved separation of electrons and holes produced by CdS and the inhibition of agglomeration of these nanostructures by combining them at the biochar surface. According to the results, 97% of chlorpyrifos was degraded by the prepared nanocomposite during the photocatalytic process. The photocatalytic activity of the synthesized nanocomposite was dependent on the parameters of time, pH, pesticide concentration, amount of used photocatalyst, which were optimized. The pseudo-first-order kinetic model derived from the Langmuir-Hinshelwood equation well describes the behavior of the experimental data in this study. It was also reused several times after washing to evaluate the stability of the synthesized photocatalyst. This study introduced a new type of photocatalyst for pesticide degradation. [Display omitted] • Biochar from pyrolysis of grapefruit peel powder provides a carbon source and improves the photodegradation property of CdS nanoparticles. • Biochar/CdS-Fe 3 O 4 photocatalysts were fabricated via a facile and cost-effective technique. • The nanocomposites exhibited higher degradation performance due to effective charge separation. [ABSTRACT FROM AUTHOR]