Investigation on the adsorption of the carbamate pesticide methomyl from aqueous solution using modified co-beta zeolite particles

Abstract

Adsorption of carbamate pesticide Methomyl by Co-Beta Zeolite particles prepared by wet ion-exchange method from aqueous solutions was studied. The effect of zeolite and pesticide concentrations, pH value, and sintering temperature on pesticide removal from an aqueous solution was studied. The change of methomyl concentration during the adsorption was followed using the UV-Visible spectrophotometer. Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS) revealed the modified zeolite morphology and elemental structure. The change of the adsorbent surface before and after dye removal was observed using the Fourier Transformation-infrared spectroscopy (FT-IR). The adsorption kinetics follows the pseudo-second-order kinetics model, and at optimal condition adsorption rate is k1 = 0.0166 g mg-1 min-1. The Langmuir, Freundlich, Temkin and Dubinin-Radushkovich adsorption isotherm models were used to describe the adsorption process. Thermodynamic parameters were also determined using experimental data. The thermodynamic study indicates that during pesticide adsorption is, chemisorption and physisorption are present at the same.