Kinetics of liquid-solid ion exchange reactions of calcium/hydrogen ions on cation exchange resin in non-aqueous media

Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt

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Manuscript received 21 January 2003, revised 3 November 2003, accepted 14 January 2004

The exchange mechanism between Ca²⁺/H⁺ in mixed solvent (water-glycerol) media on KU₂-20 (cation-exchanger) using batch technique is described. The dependence of exchange speed on temperature, particle size of the sorbent material was studied in aqueous and aqueous-glycerol media. The results showed that the exchange processes as controlled by the diffusion within the exchanger particles for the systems studied herein. The effective diffusion coefficients have been evaluated at three different temperatures. The energy barriers against the diffusion of exchanging ions have been estimated from the Arrhenius equation. Entropies of activation for the sorption processes have also been calculated