Equilibrium sorption of crystal violet by carboxymethylated cellulose with low degree of substitution

Cellulose fabric samples were carboxymethylated for different duration. The degree of substitution was changing through a maximum value during the reaction time.The equilibrium sorption of a cationic dye by cellulosic fibers of different degrees of carboxymethylation was investigated in buffered and in unbuffered systems. The sorption isotherms were interpreted by two kinds of approximations based upon Langmuir isotherm. From the sorption data extrapolated to zero dye concentration affinities were calculated. The temperature dependence of affinities gave the values of heat and entropy of dyeing which were changing along the reaction time similarly to the degree of substitution.