Flocculation Activity of Grafted Chitosan for Water Treatment

Abstract

Chitosan was grafted with 2-(dimethylamino) ethyl methacrylate monomer, or with 2-(dimethylamine) ethyl methacrylate-acrylic acid monomers. The obtained chitosan poly 2-(dimethylamine) ethyl methacrylate (I) as well as Chitosan poly- 2-(dimethylamine) ethyl methacrylate-acrylic acid (II) hybrids were evaluated in flocculation performance of kaolin suspension and also in the clarification behavior of treated tap water when combined with alum. The polymerization was carried out using potassium persulphate/sodium bisulphite redox initiation system at 60^OC for 3 hours. The obtained two grafted samples I and II were characterized using FTIR, thermal properties expressed as thermogravemetric analysis (TGA) and differential scanning calorimeter (DSC) as well as X-ray. The water clarification from kaolin suspension was evaluated for the two obtained hybrid polymers with respect to the pH, polymer dosage, and settling time. The combination between the prepared hybrid and alum was also investigated. The results showed that the grafted chitosan copolymers I & II exhibited thermal stability. The best flocculation for the two prepared hybrid I & II were observed at pH 6.5 and dosage concentration of 1 ppm with recorded turbidity of 3.01 & 2.66 NTU. The best flocculation was observed for native chitosan at pH 7.5 and 4.85 NTU. Combination between 25 ppm alum with 0.5 of each of I & II induced more water clarification with turbidity values of 1.84 & 1.65.