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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.)

Tannic acid, as a humic-like substance with phenolic hydroxyl and carbonyl functional groups, can modify the surface of Fe 3 O 4 nanoparticles (NPs). Moreover, it can improve surface properties and capacity of Fe 3 O 4 for adsorption and reduction of silver ions through complexing with them, in aqueous solutions. Therefore, Fe 3 O 4 @TA NPs have potential of reducing, stabilizing and immobilizing silver nanoparticles to generate novel magnetic silver nanocatalyst. The nanocatalyst was characterized by several techniques such as Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP), Transmission electron microscopy (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Energy-dispersive X-ray spectroscopy (EDS), Vibrating Sample Magnetometer (VSM) and Fourier-transform infrared spectroscopy (FTIR). The results of characterization showed that the Fe 3 O 4 @TA/Ag nanocatalyst was successfully synthesized. It was observed that the Fe 3 O 4 @TA/Ag NP is the useful and recyclable, which can catalyze the reduction of different dyes, including 4-nitrophenol (4-NP), Rhodamine B (RhB), and Methylene blue (MB) in the presence of NaBH 4 in the aqueous medium at room temperature. With the help of UV-Vis spectroscopy, catalysis reactions were controlled. According to results, these reactions followed the pseudo-first-order rate equation., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This paper describes the synthesis of Ag-4-ATP-MWCNT nanocomposite and its use as a modifier of working electrode. The surface of the electrochemical Ag-4-ATP-MWCNT electrode was modified with a double-stranded DNA (dsDNA) to detect daunorubicin-DNA interactions. Differential pulse voltammetry was applied to develop an electroanalytical procedure for the determination of daunorubicin and evaluate its interaction with dsDNA immobilized on the electrode surface. After the optimization of operational parameters, the linear dependence of the peak current on the daunorubicin concentration was observed in the range of 0.10×10 -8 to 1.00×10 -5 molL -1 , with the detection and quantification limits of 3.00×10 -10 and 1.00×10 -9 molL -1 , respectively. The proposed biosensor was successfully applied to validate its capability for the determination of daunorubicin in human serum and urine samples., (Copyright © 2017 Elsevier B.V. All rights reserved.)