Fundamental Study on the Production of Ultrapure Water VIII. Removal of Leachables from Mixed-Bed Ion Exchange Resins

Abstract

Abstract A study was made concerning the removal of leachables released from mixed-bed ion exchange resins. The key concerns were to determine the optimum mixed ratio of strong acid cation exchange resins (SACERs) and strong base anion exchange resins (SBAERs), which give the minimum value of total organic carbon (TOC) released from the resin mixtures and to investigate the effect of synthetic carbonaceous adsorbents on the adsorption of the leachables. The leaching rates of the leachables from the resin mixtures were dependent on the mixed ratios of SACERs and SBAERs. The TOC value for the leachables showed a minimum for a SACER-to-SBAER volume ratio of 9:1, far different from the mixed ratio in ordinary water treatment. The release of leachables from resin mixtures was mainly due to SBAER. The carbonaceous adsorbent having a higher hydrophobic surface adsorbed the leachables well from the resin mixtures.