Preparation and adsorption behavior of graft copolymer by chitosan with acrylic acid

Graft copolymer(CTS-g-AA) was prepared by grafting copolymerization of chitosan(CTS) with acrylic acid(AA) using ammonium persulfate as initiator.The effects of the amount of AA,initiator,reaction temperature and reaction time on the graft copolymerization were investigated,respectively.The structure of graft copolymer was characterized by FT-IR and adsorption behaviors of graft copolymer on Cr 3 + and Pb2+ were researched.The results show that the optimal reaction conditions of graft copolymerization were 3.5 mL of AA,0.2 g of(NH4)2S2O8,reaction temperature at 65 ℃ and reaction time in 4 h,respectively.The —COOH peaks of graft copolymer were visibly revealed on infrared spectra,showing that chitosan was successfully grafted on to the acrylic acid.The adsorption capacities for Cr 3 + on graft copolymer and chitosan were 144.7 mg/g and 116.4 mg/g and for Pb2+ were 38.1 mg/g and 18.2 mg/g,respectively.The graft copolymer has satisfactory adsorption effect for Cr3+ and Pb2+ and better than that of chitosan.Among them,it had stronger adsorption for Cr 3 + with the maximum adsorption capacity for Cr3+ being about four times as high as for Pb2+.The adsorption capacity was affected by the pH value of solution.Thus it was possible to recycle the metal ions of waste water by adjusting the pH value to control the absorption and desorption of the melal ions