Views:2 Author:Site Editor Publish Time: 2010-04-02 Origin:Site
Application of ion exchange resin: Resin and treatment of pollution.
1. SS sewage block
Suspended solids in raw water will plug the pores in the resin layer, thereby increasing the flow resistance, will cover the surface of resin particles, thereby reducing its operating capacity.
To prevent pollution of suspended matter blocking the water main is to strengthen the original pre-treatment, to reduce the water content of suspended matter. Resin layer to remove suspended solids, can be used to increase frequency and duration of anti-washing or using compressed air scrubbing and other methods.
2. Iron contamination
Yang, anion resin are possible iron contamination, contaminated by iron color of clear resin, become darker and even black; iron contaminated resin bed pressure drop will increase and may lead to bias; seriously reduce switching capacity and regeneration efficiency; resin will increase the water content; will enable accelerated degradation of anion resin.
Clear the way to iron compounds, usually with hydrochloric acid (10 ~ 15%) soak resin 5 to 12 hours, or even longer. Can also be used citric acid, EDTA and other complex processing.
3. Aluminum contamination
In the switch, the floc of aluminum compounds in the resin covering the surface, resulting in lower resin exchange capacity. Usually 10% hydrochloric acid solution or with suitable complexing agents on the aluminum contamination of resin is a collaborative anti-washing, amount of hydrochloric acid may be added 300 grams per liter of resin, concentrated hydrochloric acid (concentration 33%).
4. Calcium contamination
Ion exchange occurs out of the water Ca2 + and SO2 4 - the premature leak. Treatment with the above-mentioned iron, aluminum contamination of resin recovery the same way.
5. Calcium sulfate precipitation
When the sulfuric acid recycling type calcium Yang resins, such as improper operation, it is possible precipitation in the resin layer of calcium sulfate precipitate. At this point, not only regenerated difficult to clean, always washing up liquid hardness, and resin exchange capacity decreased.
Measures to prevent calcium sulfate precipitation, first reduce the concentration of sulfuric acid regeneration solution, the second is to accelerate the regeneration flow rate. Regeneration method can be applied step by step, its concentration gradually increased, the flow rate is slowing. Once calcium sulfate precipitation, we can use 10% hydrochloric acid soak 1 to 2 days, or using hydrochloric acid regenerated several times.
6. Silicon contamination
Silicon compounds were in the strong basic anion exchanger, especially in the strong and weak anion resin combined type of equipment and systems, and typically results in removal of silicon anion exchanger reduced efficiency. Temperature is usually 40 ~ 50 ℃ ~ 8% 4% caustic soda solution regeneration, cleaning, can strongly basic anion resin colloidal silica contamination to a minimum.
7. Oil pollution
Oil pollution of the resin is the color of their brown-black appearance, formed on the surface layer of the resin film, the resin stick together, leading to decline in switch capacity, the resin layer of uniform flow, decreased water cycle system. In addition, because the surface resin film there, so resin increased buoyancy in the water, resulting in loss of resin during backwashing. NaOH solution wash cycle? Commonly used temperature of 38 ~ 40 ℃ for 8% ~ 9% NaOH solution, since the caustic tank flows through the anion bed, sun bed, then loop back to the caustic tank cleaning. Or 200, with petroleum ether solvent or gasoline to clean the resin.
8. Organic pollution
Styrene series strongly basic anion resin vulnerable to organic pollution, its symptoms as (1) resin darker; (2) exchange capacity decreased anion bed down water cycle system; (3) increased water conductivity; (4) lower the water pH value; (5) silica content of water increases; (6) clean water increased.
Recovery method used alkaline salt, or with 10% NaCI + 4% NaOH mixture, the dosage of 3 resin bed volume, in order to slow the flow rate through the resin layer, when the first two bed volume access, the soaked resin 8 hours or place overnight, and then access the first three volume of the mixture. If the mixture heated to 40 ~ 50 ℃, better. If the mixture plus 1% sodium phosphate or sodium nitrate, or a combination of compressed air mixed resin layer, a better effect. Sodium hypochlorite cleaning solution can also be used, the content of 1%, the dosage of 3 resin volume is with a bed volume of 10% NaCI solution through the resin layer, and then soaked in sodium hypochlorite solution.