Preparation of novel carboxymethylchitosan-graft-poly(methylmethacrylate) under microwave irradiation as a chitosan-based material for Hg2+ removal.

The present study reports on a novel microwave assisted route of synthesis of carboxymethylchitosan-g-polymethylmethacrylate (CMCS-g-PMMA). The synthesized samples were characterized by Fourier transform infrared (ATR-FTIR), 13C solid-state NMR spectroscopy, thermal analysis (TGA, DTGA and DSC), X-ray diffraction (XRD) and SEM analysis to provide evidence of successful grafting. The adsorption ability of mercury (II) from aqueous media on CS, CMCS and CMCS-g-PMMA was investigated. The equilibrium was reached within 90 min. The maximum adsorption capacity was found to be 68.69, 75.75 and 87.71 mg g−1 from the Langmuir isotherm model at 25 °C for CS, CMCS and CMCS-g-PMMA respectively. Our data reveal that Hg2+ removal by the used adsorbents follow the pseudo-second-order model. The thermodynamic study revealed that the adsorption process is spontaneous and exothermic. Besides, the adsorption was found to be physical. A polyethylene glycol -water treatment of the Hg2+ loaded adsorbents (CS, CMCS and CMCS-g-PMMA) desorbed about 96% of the scavenged ions. • Synthesis of carboxymethylchitosan-g-polymethylmethacrylate for metal removal. • Mercury adsorption onto CS, CMCS and CMCS-g-PMMA has been studied. • Langmuir isotherm is suitable to describe the adsorption process. • Thermodynamic properties of the adsorption process have been determined. • Adsorption mechanism, desorption and reusability of adsorbents were investigated. [ABSTRACT FROM AUTHOR]