Equilibrium sorption of C.I.Basic Red 18 by carboxymethyl cellulose membranes

The equilibrium sorption of a cationic dye, C.I.Basic Red 18, by a partially carboxymethylated cellulose membrane at pH 4.2 was investigated. The sorption isotherm was interpreted by considering a cooperative mode of binding of the dye by the polymer. The intrinsic binding constantK, the number of consecutive polymer residues occupied by a single dye moleculen, and the cooperativity parameter were determined. In the case of the polymer with high content of carboxylate groups an additional mode of dye binding was presumed.