How to pretreat anion exchange resin?
2. Pretreatment of anion resin:
2.1 After the anion exchange resin is filled, backwash shall be carried out first to ensure 80% backwashing expansion rate to remove impurities and fine resin particles until the backwashing effluent is clear.
2.2 Feed 2-3% NaOH solution at a flow rate of 4m/h. When the outlet concentration reaches 1.5-2%, stop feeding and soak for more than 8 hours, and then rinse with cation bed effluent or deionized water until the effluent PH is 7-8. The purpose of applying alkali first is that, according to the national standard, the ex factory type of 201x7 resin is RCl type. Applying alkali first and then acid 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, the effect of acid before alkali transformation is worse than that of the former.
2.3. Inject 2-3% HCl solution at a flow rate of 3-4m/h. When the outlet concentration reaches 1.5-2%, stop the injection and soak for more than 8 hours, then rinse with cation bed effluent or deionized water until the effluent PH is about 7, and wait for regeneration.
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