How do ion exchange resins regenerate?

　　How do ion exchange resins regenerate? Chengdu Senger Environmental Protection Technology Co., Ltd. will share with you the synchronous regeneration of anion and cation exchange resins, the regeneration of cation exchange resins and the regeneration of anion exchange resins.

　　Synchronized regeneration of anion-cation exchange resin

　　(1) Firstly, the resin in the mixed bed is stratified: open the cleaning valve, the upper drain valve and start the cleaning pump, then the stratification begins; if the stratification is difficult, a small amount of acid can be used to help the resin stratification, when the resin in the mixed bed appears obvious stratification, the stratification is completed, and then open the upper valve and the middle drain valve (at the same time, the anion exchange resin is flushed until the drainage is normal before the mixed bed is opened and operated). The effluent is neutral.

　　(2) Intake of acid and alkali

　　When the ratio of alkali to alkali is more than 5 and the ratio of acid to alkali is more than 3, the alkali liquid enters from the upper row and discharges from the middle row; the acid liquid enters from the lower row and discharges from the middle row; when the inlet of acid and alkali is running at the same time, the flow rate of each pump must be kept at 600-1000L/h for no less than 30 minutes; after the regeneration of anion and cation exchange resin, the cleaning water enters from the upper row valve and the lower row valve respectively, and from the middle row valve. Drainage valve discharge, at this time to ensure that the synchronization of cleaning and the flow of water into the same; to be neutral drainage when the cleaning operation is completed.

　　The feeding of acid and alkali can also be carried out separately, according to which the way of feeding acid and alkali, flow rate and time are the same as that of synchronous regeneration. The steps are as follows: firstly, the water in the anion exchange resin column in the mixed bed is emptied, and then the resin is regenerated by alkali injection. After regeneration, the anion resin is cleaned until the water discharged is neutral, and then the water in the anion exchange resin column is emptied. When the anion exchange resin is cleaned by acid injection, the water in the anion exchange resin column should be emptied first, and then the acid solution is regenerated and regenerated. After that, the positive resin is cleaned until the discharged water is neutral, and then the water in the positive resin column should be emptied.

　　(3) Mixing of anion and cation exchange resins

　　After cleaning operation, open compressed air to mix anion and cation exchange resins until anion and cation exchange resins are evenly mixed. The pressure range of compressed air is 0.15-0.25 MPa.

　　(4) After mixing anion and cation exchange resins, they are washed by draining water from the top and bottom, and the water is discharged from the middle. The mixed bed can be put into operation when the conductivity of the effluent reaches the prescribed range.

　　REGENERATION OF CATIONIC EXCHANGE RESIN IN SICHUAN

　　(1) Acids with a specific gravity of more than 3, and all the water in the anode bed is emptied;

　　(2) Open the acid inlet valve and the upper drain valve, all other valves are closed and the acid pump is opened;

　　(3) When the acid level exceeds 500 PX above the resin, open the lower drain. The flow rate of the lower drain is the same as that of the acid inlet. At this time, the flow rate is controlled at 600-1000L/h and the acid inlet time is not less than 40 minutes.

　　After the acidification is finished, the positive bed can be cleaned directly. Firstly, the sand filtration is opened, and the precision filtration is in the upper row and the upper row. Remove the residual acid in the acid inlet pipeline and the up-and-down pipeline by opening the up-and-down inlet valve and the down-drain inlet valve. At this time, the precision filter outlet valve is opened and closed, and the acid inlet valve is closed after flushing the residual acid in the acid pipeline into the acid tank. Close the acid inlet valve under the positive bed and start cleaning. When cleaning, open the valve on the positive bed, the water in the positive bed must always overflow the resin. Do not dehydrate the resin; wash until the outlet PH value of the lower drain valve is about 7 (near neutral).

　　REGENERATION OF ANION EXCHANGE RESIN IN SICHUAN

　　(1) Alkali, with a specific gravity of more than 5, empty the water in the pudendal bed;

　　(2) Open the intake valve and the upper drain valve, all other valves are closed, and then open the alkali pump;

　　(3) When the liquid level of alkali exceeds 500 PX of resin, open the lower drain, and the flow rate of the lower drain is the same as the flow rate of alkali intake. At this time, the flow rate is controlled at 600-1000L/h, and the time of alkali intake must not be less than 60 minutes. After the completion of alkali intake, empty the shady bed of alkali.

　　When cleaning the shade bed, it is necessary to open the pump and fan of the intermediate water tank to prevent the alkali liquid from flowing back to the intermediate water tank, and then rinse the residual alkali in the alkali pipeline into the alkali tank and then start shade bed cleaning. Like the cleaning of the positive bed, the PH value of the discharged water is about 7 (neutral), and the test conductivity is less than 5.

　　IV. Special treatment of resin regeneration:

　　Ion exchange resin has been used for a long time, because some impurities (especially macromolecular organic colloidal substances) adsorbed by ion exchange resin are not easy to be eluted by conventional regeneration treatment, and it gradually accumulates and pollutes the resin, which reduces the efficiency of the resin. At this time, special treatment methods should be used, such as: cationic resin contaminated by nitrogen-containing amphoteric compounds can be treated with 4% NaOH solution, which can be dissolved and discharged; anionic resin contaminated by organic matter can increase the concentration of NaOH in alkali salt solution to 0.5-1.0% in order to dissolve organic matter.

　　V. Accelerating resin regeneration

　　According to the principle of chemical reaction equilibrium, increasing the concentration of one substance in chemical reaction can promote the reaction to the other side. Therefore, increasing the concentration of regeneration solution can accelerate the regeneration reaction and reach a higher regeneration level.

　　In order to accelerate the chemical reaction of ion exchange resin regeneration in Sichuan, the regeneration solution is usually heated to 70-80 C. The flow rate through the resin is generally 1-2BV/h, and the method of speed first and then slow can be used to give full play to the efficiency of regenerant; the regeneration time is about one hour. Then rinse the resin with soft water downstream for about one hour (water volume is about 4BV). After the rinse water is discharged, the resin is washed back with water until the rinse is colorless and turbid.