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Title: Ion-exchange selectivity coefficients in the exchange of calcium, strontium, cobalt, nickel, zinc, and cadmium ions with hydrogen ion in variously cross-linked polystyrene sulfonate cation exchangers at 25$sup 0$C

Journal Article · · J. Macromol. Sci., Part B, v. 5, no. 1, pp. 135-158

The ion-exchange selectivity parameters for the exchange of trace calcium, strontium, cobalt, nickel, zinc, and cadmium ions with hydrogen ion in crosslinked polystyrene-sulfonic acid cation exchangers were determined from equilibrium ionic distribution measurenients at 25 deg C in dilute solutions of perchloric acid and polystyrene-sulfonic acid. The selectivity behavior in perchloric acid solutions shows that the divalent ion is always preferred by the resin phase. The selectivity coefficients are a smooth function of resin phase concentration, increasing with concentration for Sr/sup 2+/ more than for Ca/sup 2+/ and Cd/sup 2+/ and being practically indepen dent of resin phase concentration for Co/sup 2+/, Ni/sup 2+/, and Zn/sup 2+/. Th e selectivity coefficients measured in salt-free solutions of polystyrene-suifonic acid show a marked dependence on the polyelectrolyte concentration, the divalent ion being preferred by the aqueous phase. This preference diminishes with the concentration of polyelectrolyte. These results are interpreted by resort to the Gibbs-Duhem equation. This thermodynamic analysis has been facilitated by the availability of osmotic coefficient data for the pure polyelectrolyte ion forms over a large concentration range. Ion-exchange selectivity predictions by using this approach accurately reflect the observed ion-exchange selectlvity behavior. (auth)

Research Organization:
State Univ. of New York, Buffalo
NSA Number:
NSA-29-018098
OSTI ID:
4346992
Report Number(s):
COO-3469-9
Journal Information:
J. Macromol. Sci., Part B, v. 5, no. 1, pp. 135-158, Other Information: Orig. Receipt Date: 30-JUN-74
Country of Publication:
United States
Language:
English