Thin Melamine Imprinted Sol Gel Coating on Silica Beads: Experimental and Statistical Physics Study

Abstract

In this work, a surface molecular imprinted polymer was developed at the silica surface by the action of ethylene glycol dimethacrylate crosslinking agent with methacrylamide surface grafts. The produced adsorbents were tested for the adsorption of melamine. The adsorption mechanism of melamine was checked by means of adsorption kinetic measurements and inspection of the models governing the adsorption isotherm. The adsorption kinetics followed a pseudo-second order kinetic reaching a maximum adsorption of 2.16 mg g−1. Beside the known binding isotherm models of Langmuir and Freundlich, the adsorption isotherms were also inspected using a statistical physics model based on the energies of binding sites. It appeared that the experimental results were better described by this last approach. The variation in adsorption capacities recorded between low and high concentration ranges was related to the entropy value.