THERMODYNAMICS OF ALKALI AND ALKALINE EARTH METAL ION-EXCHANGE ON ZIRCONIUM SULPHOPHOSPHONATES |
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| Authors: | L H Kullberg A Clearfield |
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| Affiliation: | 1. Department of Chemistry and Physics , Winthrop College , Rock Hill, South Carolina, 29733;2. Department of Chemistry , Texas A&3. M University , College Station, TX, 77843 |
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| Abstract: | The thermodynamics of alkali and alkaline earth metal ion exchange on a layered zirconium sulphophosphonate having the general composition Zr(O3PC6H4SO3H) ×(HPO4) 2?× yH2O have been investigated. Enthalpy and entropy changes accompanying the M2+ - H+ exchange (M = Na+, Cs+, Mg2+ and Ba2+)were determined by the temperature variation method. For the monovalent ions, Na+ and Cs+, the enthalpy terms favor exchange whereas the entropy terms are unfavorable. In contrast, for the divalent ions, Mg2+ and Ba2+, the exchange is due to highly favorable entropy terms. |
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