Efficient Removal of Organophosphate Pesticide Imidacloprid from Water Samples by Modified Magnetic-Silica Core-Shell Nanoparticles as a Recoverable Nano-Adsorbent

Agricultural poisons are one of the most important groups of pollutants in agricultural industries that cause environmental pollution. The main objective of this research was to remove imidacloprid from contaminated water by using modified magnetic-silica core-shell nanoparticles.
This study was conducted at the laboratory scale and batch system. The physical and structural characteristics of the synthesized adsorbent were determined by scanning electron microscopy (SEM). In addition, the effects of various parameters such as pH, initial concentration of imidacloprid, adsorbent dose, and contact time were investigated in order to determine the equilibrium isotherms and adsorption kinetics. The potential of the adsorbent for removal of imidacloprid showed no significant change after four runs of the reaction.
The highest efficiency was found to be 97.85 %, achieved at the following conditions: a contact time of 67 minutes, an adsorbent dose of 0.06 g/l, an initial concentration of 15.6 mg/l and a pH of 6.5. The correlation coefficient of Langmuir isotherm (R2=0.9843) was higher than that of Freundlich (R2=0.8). Therefore, the Langmuir isotherm model is hereby introduced to be used for predicting the adsorption behavior of imidacloprid onto the nano-adsorbent from an aqueous medium. The reaction kinetics fitted well with the pseudo-second-order model.
A modified magnetic-silica core-shell nanoparticle is a cost-effective and recoverable adsorbent for efficient removal of imidacloprid from contaminated water.