Synthesis and characterization of chitosan based super absorbent polymer modified with acrylic acid and acrylonitrile for Pb (II) metal ions removal from water

摘要

Synthesis of superabsorbent polymers based on chitosan modified by acrylic acid and acrylonitrile were conducted. The synthesis was done with a variety of modifiers including chitosan beads; acrylic acid modified chitosan (CTS-AA); acrylonitrile-modified chitosan (CTS-AN); and acrylic acid with acrylonitrile modified chitosan (CTS-AA- AN). The products were characterized with FT-IR and DSC to determine the functional group and its stability to heat treatment and to investigate its swelling ability. FT-IR analysis indicates that in CTS-AA there are functional groups - COOH and -C=C, -C≡N group in CTS-AN, and -COOH, -C=C, -C≡N groups in CTS-AA-AN. DSC analysis shows that the superabsorbent polymers are more stable to heating treatment. The swelling test shows that CTS-AA has the highest swelling ability. The superabsorbent polymers are used to reduce the levels of Pb (II) metal ions in solution. This research study pH of the initial metal ion-solution, contact time, and the initial concentration of metal ions. The optimum conditions obtained are pH of chitosan bead 7.5 and pH 4 for CTS-AA, CTS-AN and CTS-AA-AN. The optimum contact time for all the superabsorbent polymers is 45 minutes. The optimum initial concentration for chitosan beads is 16.43 mg/L. While for CTS-AA is 56.75 mg/L, 44.50 mg/L for CTS-AN, and 18.52 mg/L for CTS-AA-AN.