Abstract: A method is provided for strong base anion exchange resins containing high concentrations of pentaiodide (I.sub.5.sup.-). The resins are prepared from highly concentrated solutions of I.sub.5.sup.- and I.sub.3.sup.- ions. The exchanged ions, such as chloried (Cl.sup.-), are washed out of the resin after completion of the exchange reaction with the polyiodide ion mixture. The resulting product is a stable resin of predetermined I.sub.5.sup.- content, which is highly effective as a disinfectant for water, acting against water-borne bacteria, virus, and Giardia.

Abstract: Demand-type disinfectants are prepared from strong base anion exchange resin beads and elemental iodine. The resin is in the iodide form, and the iodine is applied with a water carrier which is recycled in contact with the resin and the stoichiometric amount of iodine to form the desired polyiodide (viz. I.sub.3.sup.-, I.sub.5.sup.-, or mixtures thereof). A homogeneous product of pre-determined polyiodide content is obtained.