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Pretreatment Method Of Strong Acid Cation Exchange Resin

Jul 21, 2020

Single bed: cation column or anion column can only be used to produce water from which cations or anions are removed.


   Double bed: male column-cathode column; deionized water can be prepared;


  Mixed bed: positive column-negative column-mixed bed. The purity of the deionized water produced is higher than that of the double bed. Can produce high-purity water. It is usually used in demanding industrial production or scientific research.


  Operation steps: resin pretreatment-packing-washing-effluent-resin regeneration



   1. Pretreatment of resin:


   1. Pretreatment of cation exchange resin: Put the resin in a clean container and rinse with clean water until the drainage is unblocked. Soak the resin in water for 12-24 hours to fully expand the resin. If the resin is dry, it should be soaked in saturated sodium chloride solution first, and then the sodium chloride solution should be gradually diluted to prevent the resin from swelling and breaking. Soak the resin with 2~5% HCl solution twice the volume of the resin for 2~4 hours, stirring occasionally. Then wash the resin with low-purity water until the pH of the solution is close to 4, and then treat it with 2~5% NaOH solution. After the treatment, wash with water until slightly alkaline, and then treat it with 5% HCl solution to make the resin become hydrogen. After zui, wash with pure water to PH=4, without Cl-.


  2. Pretreatment of anion exchange resin: Same as cationic resin. When treating resin with NaOH, increase the dosage with 5~8% NaOH solution. After the resin becomes OH type, it does not need to be treated with HCl.


   If the amount of resin is small and the requirements are high, after washing with water, add one step of alcohol washing, the effect will be better.


  Second, install column


   Wash the exchange column to remove oily impurities and rinse with deionized water. Fill the column with half a column of water, and then pour the resin and water into the column together. When packing the column, pay attention to the water in the column not to leak dry, otherwise, bubbles will form between the resins, which will affect the exchange efficiency.


   Three, cleaning, watering.


  After the column packing is completed, first use pure water to flow through the exchange column in the order of effluent. The first effluent containing impurities mixed in the column packing process should be discarded. After the effluent reaches the requirements, the raw water can be passed into the normal water production.


   Fourth, the regeneration of resin


   Ion exchange resin can be regenerated by acid and alkali after its use has failed.


  1, Yang Zhu regeneration:


  Backwashing: pass water in from the bottom of the exchange column, drain the waste water from the top, loosen the compressed resin, wash away resin particles and other impurities, remove bubbles in the resin layer, and wash until the water is clear.


   Acid addition: Add 4~5% HCl aqueous solution from the top of the column, control the flow rate, and complete the addition in about 30~45 minutes.


   Positive washing: pass water in from the top of the column and waste water flows out from the lower end of the column. The flow rate is controlled to be about 2 times the flow rate of acid addition. The first 15 minutes can be slower. Wash to PH3~4, at this time check with chrome black T, there should be no cations.


  2. Regeneration of Yin Pillar:


   Backwashing: Backwashing with yang column water, the outlet of the yang column can be connected to the lower end of the cathode column, and the yang column water can be passed into it. The conditions are the same as Yang Zhu.


  Alkali addition: Add 5% NaOH solution from the top of the column, and control a certain flow rate so that the lye is added in 1 to 1.5 hours.


   Positive washing: Pass the positive column water from the top of the column, and discharge the waste water from the lower end. The flow rate can be twice that when alkali is added. The first 15 minutes can be slower. Wash to pH 11~12. Use silver nitrate solution to check the absence of chloride ions.

Source:https://www.up-resin.com/

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