Loading of zinc oxide nanoparticles from green synthesis on the low cost and eco-friendly activated carbon and its application for diazinon removal: isotherm, kinetics and retrieval study

Diazinon (DZN) has been reported as an important pesticide with wide application in agriculture. The entry of these compounds into water resources has brought serious environmental problems due to their resistance to biodegradation; thus, this study was considered to be done to explore the process of DZN uptake and the influence of effective parameters. The study was performed experimentally and on a laboratory scale. Investigating the structure and morphology of the nanocomposite was done based on different analyses, i.e., FE-SEM, FTIR, and XRD. The experiments based on the Box–Behnken scheme were performed by surveying four important operating parameters (pH, contact time, nanocomposite dose, and DZN concentration). Optimization was performed by experiment design software and using the response surface method and analysis of the proposed model. The DZN removal efficiency was obtained 100% under optimal conditions including pH = 5, nanocomposite dose = 0.83 g/L, reaction time = 55 min, and DZN concentration = 5 mg/L. Considering the high correlation coefficient R2 = (0.9873) and RAdj2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_{{{\text{Adj}}}}^{{2}}$$\end{document}= (0.9725), the proposed model (quadratic) was approved. The results were indicative of conforming the reaction kinetic to the pseudo-second-order model and the correspondence of reaction isotherm to the Freundlich model (R2 = 0.997). Based on the obtained results, the adsorption process with AC–ZnO nanocomposite could be introduced as an efficient and eco-friendly technique to remove DZN.