Removal of basic dyes from aqueous solutions using starch-Graft-acrylic acid copolymers

Graft copolymerization of acrylic acid (AA) onto starch was carried out with ceric ammonium nitrate as initiator under nitrogen atmosphere. The grafting percentages (GP%) of starch-graft-AA (St-gr-AA) copolymers were determined. When the AA molar concentrations were 0.3 and 0.5 mol/L, GP% of St-gr-AA copolymers were 10.5% (St-gr-AA-1) and 14% (St-gr-AA-2), respectively. St-gr-AA copolymers have been used for the adsorption of basic dye (Safranine T) from aqueous solutions. Effects of various parameters such as treatment time, initial pH of the solution (pH = 2-6), initial dye concentration (50-500 mg/L), and GP% of starch graft copolymers were investigated. Basic dye removal capacities of the copolymers increase along with the augment of initial concentration of the adsorbate, GP% of the copolymers, and pH. The adsorption capacities for St-gr-AA-1 and St-gr-AA-2 reach 116.5 and 204 mg/g, respectively. Equilibrium adsorption data were obtained and fitted very well to Freundlich model. (c) 2007 Wiley Periodicals.