Gold nanoparticle chitosan composite hydrogel beads show efficient removal of methyl parathion from waste water

Abstract

Removal of pesticides from waste water is extremely important for the avoidance of serious health risks. We report an environmentally benign synthetic approach to prepare sorbent–hydrogel composite beads, composed of gold nanoparticles (GNP) embedded in a cross-linked biocompatible chitosan polymer matrix, for removal of the pesticide methyl parathion (MP). The equilibrium sorption and kinetic data, at different initial MP concentrations, are analysed using various sorption isotherm and kinetic models. It is observed that the sorption process can be best described by the Langmuir isotherm model and that pseudo second-order kinetics are followed throughout the studied concentration range. The monolayer capacity of the beads with and without the GNP composite are determined to be 58 μmol g⁻¹ and 11 μmol g⁻¹, respectively, suggesting the potential usefulness of the former for the removal of MP. The results show that the synthesized sorbent has good potential for pesticide removal.