Studies on cation exchange equilibria for the uranyl-hydrogen system

Selectivity coefficients of the uranyl-hydrogen ion exchange system have been determined in a series of sulfonated polystyrene type cation exchange resins in three different degrees of crosslinkage at four different temperatures. The standard free energies of exchange ΔG° and the heats of exchange ΔH were also estimated from the data of selectivity coefficients determined on the same resins. In general, the selectivity coefficient increased with both crosslinkage and temperature, and decreased with increasing proportion of uranyl in the resin phase. The study was further extended to the exchange system of uranyl-ammonium in order to ascertain the validity of the magnitudes of selectivity coefficients obtained for the uranyl-hydrogen system. Good results were obtained on the exchange equilibria. (author)