Graft copolymer (chitosan-g-N-vinyl formamide): Synthesis and study of its properties like swelling, metal ion uptake and flocculation

A graft copolymer of chitosan and N-vinyl formamide has been synthesized by free radical polymerization using bromate/cyclohexanone redox in an inert atmosphere. The grafting ratio, add on, and efficiency increase continuously with increase in concentration of N-vinyl formamide from 9 × 10−2 mol dm−3 to 41 × 10−2 mol dm−3, bromate ion from 0.4 × 10−2 mol dm−3 to 2.4 × 10−2 mol dm−3 and chitosan from 0.6 g dm−3 to 1.4 g dm−3. Grafting parameters decrease with increase in concentration of hydrogen ion from 2 × 10−3 mol dm−3 to 10 × 10−3 mol dm−3. Experimental results also show that these parameters i.e. grafting ratio, add on, and efficiency increase with increase in cyclohexanone concentration from 0.4 × 10−2 mol dm−3 to 1.2 × 10−2 mol dm−3, but beyond this cited range, these parameters decrease. Maximum grafting i.e. 189.5% has been found at 120 min and 40 °C. The swelling, metal ion sorption and flocculation capability have been studied, respectively. The flocculation capability of chitosan and chitosan-g-N-vinyl formamide in both coking and non-coking coals has been studied for the treatment of coal mine waste water. The graft copolymer has been characterized by Infra red (IR) spectroscopy and thermogravimetric analysis.