Features of Sorption and Proton-Desorption of Heavy Metals (M2+) from Aqueous Solutions by Biopolymers

Several features of the sorption and proton-desorption mechanisms of heavy metals (M2+) from aqueous solutions of acids and native salts (cellulose, chitosan, keratin) by modified biopolymers with acidic (Cell-COOH), salt (-OOC-W-NH3+), amine (CS-NH2), and other sorption sites were examined. Sorption isotherms of metal cations from their aqueous salt solutions (pH < 7) by biopolymers were described well in terms of the Langmuir model. The distributions of Cu2+, Fe2+, Ni2+, Zn2+, and Cd2+ in the heterophasic system H2O-H2SO4-MSO4-biopolymer were linear functions of the solution acidity in logarithmic coordinates log (KDM2+) vs. pH with tan alpha approximate to 0.5.