How to pretreat cation exchange resin?
1. Pretreatment of cation exchange resin:
1.1 After the cation resin is filled, backwash shall be carried out first to ensure 80% backwash expansion rate to remove impurities and fine resin particles until the backwash effluent is clear, colorless, tasteless and foam free.
1.2. Fill 3-4% HCl solution, 4m/h, when the outlet concentration reaches 1.5-2%, stop filling and soak for more than 8 hours, and then flush with raw water until the PH of the outlet water is 2-3 (the PH value depends on the content of strong acid anions at the inlet). The purpose of passing acid first is: according to the national standard, the ex factory type of 001 * 7 resin is RNa type. Passing acid first and then alkali can make the resin have a secondary expansion and contraction process. The purpose of pretreatment is to make the new tree vomit the oligomer that may remain in its aperture through the volume expansion and contraction during transformation. However, there is obviously only one transformation after alkali and acid, and the effect is worse than the former.
1.3 Inject 2-3% NaOH solution at a flow rate of 3-4m/h. When the outlet concentration reaches 1.5-2%, stop the introduction and soak for more than 8 hours, then rinse with cation bed effluent or deionized water until the PH of effluent is 7-8, and wait for regeneration.
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