Why does the strength of ion exchange resin decrease?

The demand for ion exchange resins in the water treatment field is very high, accounting for about 90% of the total ion exchange resin production, and they are used to remove various cations and anions from water. So, why does the strength of ion exchange resins decrease?

The main reasons for the reduced strength of ion exchange resins are: 

(1) Ion exchange resins can break down due to the action of strong oxidizers, which lowers their strength. This often happens with cation resins, for example, when excessive residual chlorine in the incoming water causes problems. However, anion resins can also degrade and lose strength when severely contaminated with organic matter. 

(2) Ion exchange resins can get damaged from repeated mechanical friction, such as frequent backwashing, rapid hydraulic transport, too high exchange flow rates, or scrubbing by air and ultrasound, which all affect their strength.

(3) Because ion exchange resins sometimes operate under high pressure and high flow conditions, if the pressure difference between the inlet and outlet is too large, the resin can get crushed and lose its strength. 

(4) During operation, if the resin expands too much—like when it swells too quickly or too much during the transformation process—repeated swelling and shrinking can weaken the resin.

(5) The thermal stability of resin is poor. When using it at high water temperatures, for example when the condensate recovery water is too hot, it often causes the resin to break apart, reducing its strength. 

(6) If resin is stored improperly and dries out, it will swell and crack once it meets water; or if the environment is turbid; or if the temperature drops below 0°C. The water inside the resin freezes, causing it to expand, crack, and break, which lowers its strength.

These are the main reasons why ion exchange resin loses strength. Currently, the largest use of ion exchange resin is in pure water treatment at thermal power plants, followed by applications in nuclear energy, semiconductors, and the electronics industry.