High effective removal of diazinon from aqueous solutions using the magnetic tragacanth-montmorillonite nanocomposite: isotherm, kinetic, and mechanism study.

Abstract

Health and environmental impact of pesticide contamination of groundwater has been reported repeatedly in many studies. The removal of diazinon from agricultural wastewater is still of great interest due to using widely in many developing countries. In the presented study, the magnetic tragacanth-montmorillonite nanocomposite was utilized as an adsorbent to remove diazinon from an aqueous solution. The adsorbent properties were characterized using FE-SEM, EDX, FTIR, XRD, BET, and VSM techniques. The influence of adsorbent dosage, pH, contact time, and initial concentration of diazinon was studied in a batch system. Different adsorption kinetics and isotherm models were used to describe the kinetic and equilibrium data. The results indicated that the adsorption kinetic was fitted better with a Elovich kinetic model, and the adsorption isotherm was well described by the Langmuir-Freundlich model, and the maximum adsorption capacity was 416mgg-1. According to Weber and Morris's model and Boyd plot, the results demonstrated that the adsorption kinetic was controlled simultaneously by film diffusion and intraparticle diffusion. Besides, a thermodynamic study showed that the removal of diazinon is an endothermic process. Considering the results, magnetic tragacanth-montmorillonite nanoadsorbent has a high capability to remove diazinon from aqueous solution.