Anion and Cation Exchange Resin Pretreatment
Pretreatment and regeneration method of ion exchange resin
The new resin to be used in the column is washed with hot water (clean tap water is also acceptable) repeatedly. The cation exchange resin can be heated at 70-80℃, while the heat resistance of the anion exchange resin is poor and can be heated at 50-60℃. water. When starting the immersion, change the water every 15 minutes, and stir it from time to time during the immersion. After changing the water 4-5 times, you can change the water every 30 minutes. The water is changed 7-8 times in total. The water doesn't have brown color, and there is little foam.
After washing with water and then acid-base treatment, the cation exchange resin can be treated as follows:
1. Slowly flow through the resin with 1N hydrochloric acid. The amount is about 2-3 times the volume of the strong acid cation resin, 3-5 times the volume of the weak acid cation resin, and 1.5 times the bed volume per hour.
2. Rinse with water, the pH of the effluent is about 5, and use 3 times the volume of the resin to flow through the resin with 5% NaCl solution at the same flow rate as 1.
3. Use 1NNaOH to flow through the resin, the dosage and flow rate are the same as 1.
4. Rinse with water until the effluent pH is about 9.
5. Use 1N hydrochloric acid or sulfuric acid to convert the resin to H type. The amount is 3-5 times the volume of the resin, and the flow rate is the same as 1.
6. After the acid flow is finished, rinse with deionized water until the PH value of the effluent is above 6, then it can be put into use.
For the acid and alkali treatment sequence after washing the anion exchange resin, the alkali-acid-alkali sequence can be adopted. The dosage and flow rate of acid and alkali correspond to the cation resin, and the weak base anion resin corresponds to the weak acid cation resin.
Resurrection treatment of ion exchange resin:
1. Iron pollution: After the resin is contaminated by iron, the color becomes darker or even black. You can use 10% hydrochloric acid twice the volume of the resin to pass through the resin layer at a flow rate of about 0.6m/h, and then clean it with the same flow rate of 40℃ water , And finally regenerate with excess NaOH (cation resin).
2. Silicon pollution: Silicic acid adsorbed by resin can easily polymerize into high polymer and precipitate in resin under low PH conditions. It can be soaked in 40-50℃, 6%-8% NaOH solution, and then washed with water. To avoid silicon pollution, the concentration and temperature of the regenerant should be appropriately increased.
3. Organic matter pollution: The anion resin is easily polluted by the organic matter in the water, causing the resin to change color and black, the conductivity of the water rises, the PH value decreases, and the efficiency decreases. In this way, 10 times the volume of the resin and 8% NaCl at a temperature of 40°C can be used. A 4% NaOH mixture can be passed through the resin layer at a flow rate of 0.6m/h, or soaked for 24h, a better recovery effect can be obtained.
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