What effect does chlorine have on cation exchange resins?
The presence of free chlorine or other oxidizing agents in the feed water can lead to resin degradation over time. Anion exchange resins are very sensitive as oxidants attack the functional amine group resulting in loss of resin capacity and impaired performance. Continuous exposure of anion resins to >0.05 ppm free chlorine should therefore be avoided. In the case of a cation resin, oxidation occurs by de-crosslinking the copolymer matrix, leading to an increase in water retention capacity and resin swelling. This results in weakening of the mechanical integrity of the resin and wet volume capacity loss. Temperature and chlorine concentration both impact the rate of de-crosslinking. While it is not possible to accurately predict resin life when other factors are considered, the following guidelines for feedwater chlorine levels will maximize the life of cation resins. Recommendations for Maximum Free Cl2 Limits for DOWEX Cation Exchange Resins (91KB PDF) Like chlorine; chloramines, ch
