Microwave-assisted green synthesis of xanthan gum grafted diethylamino ethyl methacrylate: An efficient adsorption of hexavalent chromium.

We report the development of a novel graft copolymer, diethylamino ethyl methacrylate grafted xanthan gum (mwXG-g-DEAEMA), by microwave heating. The synthesized graft copolymer was used for potential application of Cr(VI) adsorption. The structure, thermal stability and morphologies of XG and mwXG-g-DEAEMA were characterized to verify the adsorbent formed under optimized reaction conditions. FTIR, XRD, TGA and SEM techniques were used for characterization of XG and mwXG-g-DEAEMA. Furthermore, 1H NMR spectroscopic analyses predict the probable structure of copolymer. Based on the NMR data, a plausible mechanism for copolymer formation has been proposed. The effects of adsorbent loading, pH, contact time and equilibrium concentration of the Cr(VI) adsorption were investigated batch wise. The Cr(VI) adsorption process followed the pseudo-second-order rate model and equilibrium data were best described by Freundlich isotherm model. This work will encourage researchers to focus on this facile green technique for the synthesis of adsorbent with enhanced adsorption capacity.