Abstract

Synthesis of new low cost carbohydrate polymers for dyes removal from their solutions

Author(s): Abdul Rahim Samerkandy, Kh.M.Mostafa

Synthesis of new low cost natural carbohydrate polymers based on crosslinking pregelled starch-using epichlorohydrin as a cross-linking agent via graft copolymerization was studied in detail using potassium monopersuphate in presence of Fe2+ redox pair as initiator. Different factors affecting the graft polymerization reaction such as potassium monopersuphate, ferrous ion, sulphuric acid and methacrylamide concentrations, material to liquor ratio in addition to polymerization time and temperature were studied systematically. This was done to prepare poly (MAam)-cross-linked pregelled starch graft copolymers having different graft yields and their uses for removal of different classes of dyes namely acid, disperse and basic dyes from their solutions. In addition, the grafting parameters were studied with respect to graft yield and graft reaction efficiency %. Based on the results obtained, appropriate conditions for grafting methacrylamide onto cross linked pregelled starch were established and the graft yield is higher under the following conditions: using 60mmol/Lpotassiummonopersulphate as initiator, 40mmol/Lferrous ion concentration, 50mmol/L, sulphuric acid;material to liquor ratio 1:7.5; 50% methacrylamide concentration (based on weight of substrate), reaction time, 60min; and polymerization temperature, 400C. Finally, utilization of the resultant copolymers for dyes removal reflects the role of the copolymer as effective adsorbent for the removal of acid and disperse dyes from aqueous solutions, beside little or no affinity to basic dye. It would be interesting to use these copolymers as sorbent for the economic treatment of effluent containing particularly acid dyes