Hydration and dehydration of cadmic and nickel forms of sulfur-containing ion-exchange fiber

Ion-exchangers intensively interact with polar solvents. Studying of the mechanism of interaction of chemisorption fibers with water and definition of amount of kinetic non-uniform solvent is necessary for understanding of processes of hydration and dehydration. The data obtained are of practical and theoretical interest in the study of ion exchange and complexation. The purpose of this work - the study of hydration and dehydration during chemisorption-fiber VION COP-3 in cadmium and nickel forms The state of water in sulfur-containing ion-exchange fibers with functional groups -SO 3H was estimated by the thermogravimetric analysis and isopiestic methods. Isotherms of sorption of vapors of water are received. The presence of water with different degrees of binding was confirmed. Influence of the nature of the ions sating fiber on the course of isotherms of sorption is revealed. From results of thermogravimetric researches, the hydration numbers of fiber corresponding to each stage of water removal were determined. The Gibbs free energies of hydration of cadmic and nickel forms of fiber were calculated. The greatest changes of Gibbs free energies are characteristic for the initial stage of sorption of vapors of water.