A new combustion method for the synthesis of copper oxide nano sheet and Fe3O4/CuO magnetic nanocomposite and its application in removal of diazinon pesticide

Abstract

Pesticides used in agriculture and their entry into water is one of the most important environmental problems in the world. In recent years, much attention has been paid to the removal of pesticides, such as diazinon, by researchers. The subject of this research is the remove of diazinon from water using a CuO nanosheet and Fe3O4/CuO nanocomposite, synthesized by a new combustion method. The effect of some factors such as contact time, pH, temperature, the amount of adsorbent, concentration of diazinon and presence of electrolyte has been investigated. Isotherm, kinetics and thermodynamics of absorption in the optimal conditions were investigated. Another goal of this study is to use a fast and cost-effective method for the synthesis of CuO nanosheet and Fe3O4/CuO nanocomposite. After synthesis, were characterized by methods such as FTIR, XRD, FE-SEM, VSM, EDX and element distribution. The results showed that the Fe3O4/CuO nanocomposite is better than CuO nanosheet for this purpose. In optimal conditions, pH = 7, absorbent concentrations of 0.035 mg/ml with a diazinon concentration of 2 mg/L and contact time of 10 min removal percent of this pesticide was 94%. The standard deviation percentage of the method for the real sample, with four repetitions, was equal to 3.8%. The recovery for three repetitions was 97.6% in the range of the real sample. Langmuir isotherm and second-order kinetics were investigated to explain the absorption mechanism. Thermodynamic investigations have shown that the absorption is a spontaneous process at low temperatures (ΔH<0, ΔG>0).