Ion Exchange Resin Limitations

When a resin bed has been contaminated with organic foulants, a procedure is available that can help to restore the resin. Three bed volumes 

Physical stability of a properly made cation or anion exchange resin is more than adequate for any of the typical conditions of operation. These resins can be made to have a physical crush strength in excess of300 grams per bead. 

The amine functionality of weak base resins is more stable in the free-base form than that of strong base resins. Styrene-divinylbenzene weak base resins may be used at temperatures up to 100°C with no adverse effects. 

Chemical attack most frequently involves degradation due to oxidation. This occurs primarily at the cross-linking sites with cation exchange resins and primarily on the amine sites of the anion exchange resins. From an operating standpoint and, more importantly, from a safety standpoint, severe oxidizing conditions are to be avoided in ion exchange columns. 

The degradation of anion resins occurs not only by chain scission, but also at the more vulnerable nitrogen on the amine functionality. As an example, the quaternary nitrogen on Type I strong base anion resins is progressively transformed to tertiary, secondary, primary nitrogen and finally to a nonbasic product. 

---