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How To Regenerate Ion Exchange Resin

Jul 23, 2020

Ion exchange resin is a kind of water treatment filter material commonly used in many industries. It can soften hard water, can remove salt, can remove anions and cations, can purify and so on. Ion exchange resin can be regenerated, but how is it regenerated?

After the ion exchange resin has been used for a period of time, the adsorbed impurities are close to the saturated state, and it is necessary to carry out regeneration treatment. The ions and other impurities adsorbed by the resin are eluted and removed with chemical agents to restore the original composition and performance, that is, ion exchange Resin regeneration.

1. The simple regeneration method of macroporous adsorption resin is to use solvents of different concentrations to elute according to the polarity from large to small, then soak and elute with 2-3BV dilute acid and dilute alkali solution, and wash with water until the pH value is neutral. be usable.

2. The sodium type strong acid cation resin can be regenerated with 10% NaCl solution, and the amount of medicine used is 2 times of its exchange capacity (the amount of NaCl used is 117g/l resin); the hydrogen type strong acid resin is regenerated with a strong acid. The calcium adsorbed by the resin reacts with sulfuric acid to form calcium sulfate precipitate. For this reason, it is advisable to pass 1-2% dilute sulfuric acid for regeneration.

3. Chlorine-type strong alkaline resin is mainly regenerated by NaCl solution, but adding a small amount of alkali will help to dissolve and wash out the pigment and organic matter adsorbed by the resin, so it is usually regenerated with alkali salt solution containing 10% NaCl + 0.2% NaOH The conventional dosage is 150-200g NaCl and 34g NaOH per liter of resin. The OH type strong alkali anion resin is regenerated with 4% NaOH solution.

4. Some decolorizing resins (especially weakly basic resins) should work under slightly acidic conditions. At this time, dilute hydrochloric acid can be introduced to reduce the pH of the resin to about 6, and then wash with water and backwash each time.