Adsorbent composites of montmorillonite and chitosan of different molecular weight, obtained by gamma irradiation

Abstract

This work focuses on the structure and dye adsorption properties of different composition montmorillonite:chitosan (Mt:C) compounds for the remediation of water, using C of different molecular weights, easily obtained by gamma irradiation of C without further need of reagents. Chemical structure was characterized by FTIR, and differences in specific area and morphology were analyzed through BET and SEM. The lower molecular weight C eases the preparation of the compound and provides a higher specific area. Different intercalated - exfoliated behaviors were also observed through XRD, depending on the compositions and the molecular weight of the C samples. Cationic and anionic dyes were chosen as analogic model pollutants to carry out the adsorption experiments, followed through UV-Vis, and were found to fit with a pseudo-second order kinetic model. Adsorptions were also explored under different pH and dye concentrations. Results turned out to be promissory for the anionic dye, with a synergetic effect for the compounds with double proportion of Mt over C.