What is ion exchange resin? What is the preservation method and regeneration method?

What is ion exchange resin?

The ion exchanger of organic monomer particles made of polymer copolymer by chemical synthesis method is called ion exchange resin. Ion exchange resins are cross-linked structural skeletons, fixed ionic groups that are chemically bonded to the pedestal, and exchangeable ions that use ionic bonds as fixed groups and charge with opposite signs. The ion exchange resins are classified as follows. (1) Divided according to function: Strong acid resin Its exchange group such as sulfonic acid group-SO3H. Strongly basic resin The exchange group such as quaternary ammonium (I) type -CH2N (CH3) 3OH; quaternary ammonium (II) type -CH2N (CH3) 2C2H4OH? OH. Weak acid resin The exchange group such as primary amino group -CH2NH2; secondary amino group -CH2NHR (R is a hydrocarbon group); tertiary amino group -CH2NR2. Redox resin The exchange groups such as -CH2SH; Ar (OH). Amphoteric resin The exchange group such as -NR2; -COOH. CH2COOH chelating resin The exchange group such as -CH2-N CH2COOH. (2) According to structure: gel type and macroporous resin. (3) According to the monomers of the polymer: styrene; acrylic; phenolic; epoxy; vinylpyridine; urea-formaldehyde and vinyl chloride. (4) According to usage: industrial grade; food grade; analysis grade; nuclear grade; bunk bed resin; high flow rate mixed bed resin; moving bed resin and cover filter resin etc.

Resin storage method:

Ion exchange resin cannot be stored in the open air. The temperature of the storage place is 0-40°C. When the temperature of the storage place is slightly below 0°C, clear saturated saline and resin should be added to the packaging bag. In addition, when the storage temperature is too high, it not only makes the resin easy to dehydrate, but also accelerates the degradation of the anion resin. Once the resin loses water, water cannot be added directly during use. It can be soaked in clear saturated saline, and then gradually diluted with water to wash away the salt. It should be kept moist during storage.

Resin pretreatment:

The new resin to be used for packing is first washed repeatedly with hot water (clean tap water). The cation exchange resin can use 70-80°C hot water, and the anion exchange resin has poor heat resistance, 50- 60°C hot water. At the beginning of the immersion, change the water every 15 minutes. Stir occasionally during the immersion. After changing the water 4-5 times, you can change the water every 30 minutes. The total water change is 7-8 times. The washing water does not 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 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, use 3 times the resin volume 5% NaCl solution to flow through the resin, the flow rate is the same as 1.
  3. Use 1N NaOH to flow through the resin with the same dosage and flow rate as 1.
  4. Rinse with water until the PH of the effluent is about 9.
  5. Use 1N hydrochloric acid or sulfuric acid to convert the resin to H-type. The dosage is 3-5 times the volume of the resin. The flow rate is the same as 1.
  6. After the acid flow, rinse with deionized water until the PH value of the effluent is above 6, and then it can be put into use.

For the order of acid and alkali treatment after washing the anion exchange resin, the order of alkali→acid→alkali, acid and alkali dosage and flow rate can be used. Strong alkali resin corresponds to strong acid resin, weak alkali resin corresponds to weak acid resin.

 Resuscitation treatment of resin:

In the process of using ion exchange resin, after a period of operation, the quality of the effluent will gradually decline and the exchange capacity will gradually decrease. This is generally due to contamination of the resin during operation. In the extraction of wastewater and biochemical substances, due to the more complex ingredients, the resin is more susceptible to pollution, so appropriate measures should be taken for resurrection treatment, and different resurrection treatment processes are used for different situations

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