Chitosan-g-poly (acrylonitrile-co-acrylic acid) for wastewater treatment application

Abstract

Chitosan is a biodegradable natural based polymer obtained from chitin (N-deacetylated derivative), the second most abundant polysaccharide after cellulose and soluble in most organic acids. Graft copolymerization of poly (acrylonitrile-co-acrylic acid) onto chitosan has been successfully carried out using potassium persulfate as an initiator in an aqueous medium. The PAN and PAA homopolymer formed during the reaction were removed from the Chitosan grafted copolymer by Soxhlet extraction using ethanol as the solvent.  The prepared graft copolymerization was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) to confirm the formation of the copolymer. The prepared chitosan-g-copolymer at ratio 25:75% of AN-co-AA was treated with metal solutions containing cadmium ions, times and pH at room temperature. It[Am1]  was found that the optimum condition was pH=5, Time 120min and dose of adsorbent 3 mg /L. The results revealed that the chitosan-g-copolymer prepared was excellent in removing the heavy metals than the copolymer alone. Hence, chitosan-g- poly- AN-co-AA could open the way for wastewater treatment. The thermal stability and the electrical conductivity for all prepared samples before and after grafing were measured. By studying the thermal stability at the different ratio of AN and AA in samples co1, co2, co3, it was found that the most thermal stability sample ratio is co3 due to increasing the ratio of AN.  While in sample co1 with a high ratio of AA, the thermal stability decrease according to the fast decomposition of –COOH of acrylic acid. The conductivity was 3.85x10-7 which is more than the copolymer without chitosan, which increases the electron density of the copolymer through the end group effect. As the result of σ has a range 10-8 S/cm-1 10-6 S/cm-1so, all the prepared sample can be used as an electrostatic dissipation application.