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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 $$R_{{{\text{Adj}}}}^{{2}}$$ R Adj 2 = (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.

This article was aimed at investigating the removal of metronidazole (MNZ) from aquatic solutions by modified activated carbon (MAC) with amine groups. The effect of various parameters on the adsorption rate such as the initial pH, adsorbent dose and initial concentration of MNZ and contact time were scrutinized. MAC was characterized by Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller techniques. The obtained results illustrated that under the optimum conditions (pH = 3, contact time = 50 min, initial MNZ concentration = 5 mg/L and MAC dose = 0.5 g/L), the maximum adsorption efficiency was 95%. Furthermore, the kinetic studies indicated the applicability of the pseudo-second-order kinetic model, whereas the adsorption isotherm fitted well with the Freundlich model (0.996), and the maximum adsorption capacity was 66.22 mg/g. The SBET and the total pure volume of MAC were 706.92 m2/g and 0.532 cm3/g, respectively. Also, the regeneration tests demonstrated that MAC had good stability after five cycles (73%). It can be concluded that MAC, as an effective adsorbent, has a high ability to remove MNZ from aqueous solutions.

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