Properties of a New Strong Base Anion Exchanger Containing Structurally bound Tertiary Sulfonium Cations

Abstract

Selectivity coefficients, rates of anion exchange, water absorption isotherms, and the absorptions of Zn(II) and Fe(III) from concentrated electrolyte solutions were measured using a new, methylene cross-linked, strongbase anion exchanger containing structurally-bound tertiary sulfonium cations. The selectivity coefficient scale, determined using thirteen anion salt forms, was nearly identical with that for quaternary ammonium type anion exchangers. The greater the water uptake at saturation vapor pressure by a given salt form the greater the bromide ion affinity. The tertiary sulfonium anion exchanger was appreciably more hydrated at low water vapor activities than the quaternary ammonium type, whereas the converse held for high water activities. The self-exchange of bromide ion in the sulfonium exchanger at 25 deg occurred with a self-diffsion coefficient of 1.18 x 10/sup -7/ sec/sup -1/, which value is notably smaller than the coefficient observed with a comparable quaternary ammonium type exchanger at the same temperature. Micro-quantities of Zn(II) and Fe(III) were strongly absorbed from hydrochloric acid and lithium chloride solutions, and this absorption increased with electrolyte concentration in a manner similar to that found with quaternary ammonium type anion exchangers. (auth)