|Author||Kraus, K. A. ♦ Raridon, R. J.|
|Source||United States Department of Energy Office of Scientific and Technical Information|
|Subject Keyword||CHEMISTRY ♦ BARIUM ♦ BERYLLIUM ♦ CATIONS ♦ CESIUM ♦ CHEMICAL REACTIONS ♦ COBALT ♦ EUROPIUM ♦ ION EXCHANGE ♦ LANTHANUM ♦ POTASSIUM ♦ RESINS ♦ RUBIDIUM ♦ SODIUM ♦ STABILITY ♦ TEMPERATURE ♦ THERMODYNAMICS ♦ WATER ♦ ZINC|
|Abstract||The temperature dependence of a number of cationexchange equilibria (tracers of Na/sup +/, K/sup +/, Rb/sup +/, Cs/sup +/, Be/su p ++/, Ba/sup ++/, Co/sup ++/, Zn/sup ++/, La/sup +3/, Eu/sup +3/ vs. H/sup +/; tracers of K/sup +/ , Rb/sup +/, Cs/sup +/ and Ba/sup ++/ vs. Na/sup +) was studied in dilute aqueous electrolyte solutions. The temperature range was 0 to 150 deg for exchanges with the H/sup +/-form of the resin and 0 to 200 deg for those with the Na/sup +/-form. The upper temperature limits were imposed by the stability of the resin (H/sup +/-form) and the "safe" operating range of the equipment (Na/ sup +/-form). Apparent heat ( DELTA H'), entropy ( DELTA S-bar',) and heat capacity ( DELTA C-barp') changes were computed for the ion-exchange equilibria. In all cases DELTA C-barp' was positive; in a few cases it was quite large (up to 20 cal/deg/equiv.). Good agreement between calculated and observed selectivity coefficients could be obtained by assuming DELTA C-barp' to be constant which leads to a linear variation oi DELTA H-bar' with temperature T, and oi DELTA S-bar' with log T. In inany cases DELTA H-bar' becomes zero in or near the temperature range studied (minima in the selectivity coefficient vs. temperature curves); this appears to be one reason why values of DELTA H-bar' for ion-exchange reactions are oiten small. (auth)|
|Learning Resource Type||Article|
|Publisher Department||Oak Ridge National Lab., Tenn.|
|Journal||Journal of Physical Chemistry|
|Organization||Oak Ridge National Lab., Tenn.|
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