Synthesis, characterization and metal uptake capacity of a new carboxymethyl chitosan derivative

Chemical modification of chitosan (Cs) and its derivatives via graft copolymerization can enhance their properties and consequently expands their potential applications. Carboxymethyl chitosan (CMCs) was prepared and characterized by FTIR spectroscopy, elemental analysis and X-ray diffraction. Graft copolymerization of N-acryloylglycine (NAGly) onto CMCs; using 2,2-dimethoxy-2-phenyl acetophenone (PI) as photoinitiator was carried out under nitrogen atmosphere in aqueous solution. Evidence of grafting was confirmed by comparison of FTIR spectra of CMCs and the graft copolymers as well as the 2D-X-ray diffraction patterns, elemental analysis and the difference in solubility profiles before and after grafting. The effects of concentration of NAGly, PI and reaction time on the extent of grafting were investigated by determining the grafting percentage and grafting efficiency. With other conditions kept constant, the obtained optimum grafting conditions were: CMCs = 0.1 g, NAGly = 0.4 g, PI = 0.02 g and reaction time = 1 h. A preliminary study was then carried out to evaluate the capacity of the prepared new graft copolymer to uptake copper ions from aqueous systems. This preliminary investigation of the prepared graft copolymers showed that they may be tailored and exploited to expand the utilization of these systems in metal ions uptake and treatment of wastewater. (C) 2008 Elsevier Ltd. All rights reserved.