Abstract
A study was made of the adsorption removal of leachables from typical strong acid cation exchange resins (SACER, one porous and one gel type, H form). The adsorbents used to eliminate the leachables were strong base anion exchange resins (SBAER, OH form) paired to each SACER and synthetic spherical carbonaceous adsorbents differing in pore volume and pore size distribution.
The leachables were obtained by soaking SACERs in purified water of TOC 100μgC/L or less at elevated temperature (70°C). The Leachables contained components with molecular weights (MW as a polystyrenesulfonate) of 500600, 1, 4002, 000, 3, 1003, 500 and about 5, 000, as determined by gel filtration chromatography and MW around 200 components including monomeric aromatic sulfates such as p-sulfobenzoic acid and p-hydroxybenzenesulfonic acid, as shown by reverse phase chromatography. The highest MW component and MW less than 186 substances were found to be the most difficult to remove with SBAERs. The carbonaceous adsorbents adsorbed well the residual leachable components which could not be removed by SBAERs. The adsorbent having many pores of less than 50Å in diameter was particularly effective. Thus possibly the unknown component of MW less than 186 is non-ionic and comes from a hydrophilic substance.
