How to Prevent Resin Pollution by Ion Exchange Resin Manufacturers

　　How to Prevent Resin Pollution in Sichuan Ion Exchange Resin Factory

　　Most ion exchange resins can be contaminated or inclusion by suspended matter. When PH changes, relatively insoluble salts such as bicarbonate will precipitate. In addition, when some substances are adsorbed or ion exchanged, they are not easily removed by normal regeneration steps, so they will be deposited on the resin causing pollution.

　　Normal cleaning can prevent the deposition of pollutants and prolong the service life of resin.

　　Increasing regeneration dosage and regeneration times (increasing temperature) can reduce pollution and prevent permanent adsorption of inclusions.

　　It is a very useful method to contact ion exchange resin with enough regenerant and adopt normal cleaning steps in the exchanger, which has been proved by operation practice.

　　If these precautions have been adopted, but the operation of the equipment has deteriorated, this may be the following reasons:

　　(1) Loss of resin content in operating equipment.

　　(2) If the quantity of ions to be removed increases, the output of the equipment will be reduced.

　　(3) Operating errors; the regeneration conditions are not suitable and the operation is not in accordance with the regulations.

　　(4) Hardware failure of factory engineering.

　　(5) Resin contamination or degradation.

　　Of the above items, (4) is the most difficult to judge. (2) It is possible to regularly analyze the quality of water supply and timely adjust the corresponding operation. (3) It is easy to check. If the steps of backwashing, the volume of elution and the concentration of regenerant are checked so as to meet the requirements of operation rules, such as (1), (2), (3), (4), the resin should be sampled and analyzed.

　　Resin sampling

　　The key to resin evaluation and conclusion is how to sample. If this is not mastered, the analyst will provide sampling methods. For example, if mixing resin or other air mixing devices are installed, the resin in the bed is generally stratified after backwashing. According to the regeneration and operation mode, the contamination of top resin can vary greatly, so the sample will not be representative. Therefore, it is necessary to sample at different bed heights before mixing, or to obtain core samples before mixing before sending them to analysis.

　　Cleaning steps:

　　According to the nature of pollutants, different steps are taken to clean the contaminated resin, which will be discussed in this paper.

　　Steps for sterilization

　　Preface

　　Sometimes polluted water enters the ion exchange system and the resin will be contaminated by bacteria or algae. If the resin bed is found to be contaminated, the following methods can be used:

　　Peracetic acid

　　Peracetic acid, a derivative of hydrogen peroxide, has broad-spectrum bactericidal effect on microorganisms. Research shows that peracetic acid is increasingly used in human medicine for bactericidal, fungal, spore and antiviral effects.

　　Because of its broad-spectrum bactericidal properties, peracetic acid can also be used as a broad-spectrum bactericide for resins (the joint development of Degussa Technology Application Department and Homdury Chemical Plant). With 0.2% peracetic acid solution (water solution, reaction time is 1 hour), 104-105/ml including fungal sludge can be eliminated to zero. Short-term washing with peracetic acid is very useful (generally 45 minutes or 10-15 bed volume).

　　In addition to good bactericidal effect, peracetic acid (according to the test) has no effect on the exchange performance of the cation resin and the anion resin.

　　If peracetic acid is used as a disinfectant, whether it is a positive resin or a negative resin, the following steps can be taken:

　　1. If used in anion resin, the resin will be completely invalid, because peracetic acid must be used below PH8.

　　2. Prepare 1-bed volume (BV) (i.e. 1 liter/liter resin) peracetic acid solution with a concentration of 2%.

　　3. Inject 1BV disinfectant, flow rate is 5VB/h, displaced water is removed from the ditch.

　　4. When all peracetic acid is injected, close all valves and immerse in acetic acid solution for at least 1 hour.

　　5. Rinse the fungicide out and use raw water at a flow rate of 5 BV/h for at least 60 minutes, then rinse quickly for 30 minutes.

　　6. Recycled resin and put into operation.

　　formaldehyde

　　If formaldehyde is used as a disinfectant, the following steps can be taken:

　　Formaldehyde solution of three bed volumes (BV) was prepared, so it must be diluted 80 times. The solution can be injected by regenerative spraying system with a concentration of 0.5%.

　　The 1BV fungicide was injected at a flow rate of 5BV/h and displaced water was discharged into the ditch.

　　If possible, drain to a level of 50 mm on the resin surface.

　　Inject the second 1BV bactericide solution at the same flow rate as before. Leave it in the equipment for at least 8 hours and preferably overnight. Formaldehyde should smell at each drainage valve.

　　Wash and discharge with raw water until formaldehyde can not be detected by Schiff test at the discharge point.

　　The resin is regenerated twice (double regeneration) and then put into operation.

　　Iron (and manganese) pollution

　　Remedies:

　　Anodic resin

　　Hydrochloric acid can be used for regeneration, but the piping system of the equipment must be made of hydrochloric acid resistant material. Using 6% hydrochloric acid, using three bed volumes, and contacting the hydrochloric acid in the middle with resin for more than two hours (heating to 40 C is more advantageous). The resin is then regenerated twice with 10% brine and put into operation.

　　Organic Pollution and Treatment

　　The most commonly used method is brine, which is as follows:

　　Resin must be treated after failure.

　　Three bed volumes of 10% brine W/V, including 2% sodium hydroxide W/V, should be prepared first.

　　Salt water of one bed volume flows through the exchange bed at a flow rate not higher than 2BV/h, and then enters the second bed volume of saline water. The longer it stays in the bed, the better, not less than 4 hours. If it can be stirred, the better it is in immersion.