EFFECT OF ETHYL XANTHOGENATE ON SORPTION OF AN ACID DYE ON POLYESTER FIBERS .2. KINETICS AND THERMODYNAMICS

Data are presented on the kinetics and thermodynamics of adsorption of Sirius red 4B on untreated polyester fibers along with the uptake of the same acid dye on polyester fibers treated with constant amounts of potassium ethyl xanthogenate at different temperatures. Temperature increases of the system decrease the adsorption of Sirius red 4B on untreated polyester, but increase uptake on polyester treated with ethyl xanthogenate. Sorption equilibria, specific rate constants, diffusion coefficients, activation energy, standard affinity, enthalpy and entropy of reaction have been determined in these processes. The results show that adsorption of Sirius red 4B on untreated polyester in the temperature interval tested probably takes place by means of H-bonds between the phenolic hydroxyl groups of the dye and the carboxyl end-group of the polyester. Also, on the basis of these compounds' molecular structures, the results suggest that dye uptake by treated polyester probably takes place by means of a nucleophilic attack of the negatively charged-S- group of the ethyl xanthogenate ion taken up by the fiber on the carbonyl group of Sirius red 4B.