Preparation Of Phytic Acid - Chitosan Polymer And Study On Adsorption Performance Of Heavy Metal Ions

Heavy metal pollution is an important cause of water pollution, and electroplating wastewater is one of the most important sources of water heavy metal pollution. The way to remove heavy metal ions in waste water with high efficiency, especially the trace heavy metal ions has been one of the most difficult problems. Usually, industrial wastewater is treated with precipitation, membrane filtration, ion exchange, adsorption etc. By contrast, biological adsorbents such as chitosan are widely concerned because of good efficiency, high selectivity.In this work, firstly we made a novel type of chitosan derivative using phytic acid and epichlorohydrin as crosslinking agent. The ratio of phytic acid and epichlorohydrin was studied, and the proportions and structures of cross-linked chitosan were characterized by DSC, TGA and XPS. When-NH2 groups of chitosan molecules and-OH groups of phytic acid molecules is the ratio of 1:2, crosslinking degree reaches 6.06%. Meanwhile, adsorption capacity of modified chitosan is greater than the value of primary chitosan.Additionally, the crosslinked chitosan was prepared into resins, different conditions about adsorption performance of the Cu (â…¡) and Ni (â…¡) static are optimized. The mechanism about adsorption of Cu (â…¡) and Ni (â…¡) before and after the crosslinked chitosan resin has been characterized by XPS. The results show that maximum adsorption capacity of Cu (â…¡) reaches 122.70 mg/g, the value for Ni (â…¡) is 202.43 mg/g. XPS shows that-NH2 is the major group for adsorption of Cu (â…¡), for nickel ion the role of-NH2 and-OH functions together. The crosslinked chitosan resins for Cu (II) and Ni (â…¡) adsorption process are according with pseudo-second order kinetic, and adsorption process is chemical adsorption.In order to simplify the preparation process and industrialized convenience, a kind of porous membrane was prepared from the crosslinked chitosan and non-woven fabric. Results show that the load rate of the crosslinked chitosan on PDMF was 50%. The maximum adsorption of composite membrane for Ni (â…¡) is 53.13 mg/g, which indicates a larger adsorption capacity for Ni (â…¡). The crosslinked chitosan composite membranes for Ni (â…¡) adsorption process are according with pseudo-second order kinetic, and adsorption process is chemical adsorption. Adsorption process is mainly the heterogeneous adsorption.