As the chemical substances and other impurities separated from the water are deposited on the surface of the membrane, it will cause environmental pollution and harm to the membrane, and then endanger the flow rate and service life of the membrane. Therefore, cleaning the uf filter membrane on time after a period of use can reasonably repair the diffusion coefficient of the uf filter membrane water and prolong its service life. Commonly used cleaning methods are organic chemical cleaning and physical cleaning.
1. Physical cleaning method of uf filter membrane
①. Adiabatic process cleaning: close the uf filter membrane water gate valve and open the concentrated water inlet and outlet gate valves to expand the flow rate to clean the membrane surface, which reasonably removes many soft impurities on the membrane surface.
②. Industrial pure water cleaning: Due to the improved purity of water, the solubility is improved. When cleaning, you can first use ultrafiltration water to remove loose stains on the surface of the film, and then use a pure water circulation system to clean.
③. Backwashing: that is, the cleaning water enters from the ultrafiltration membrane port of the membrane and passes through the membrane to the side of the concentration port. The backwash method can reasonably remove the involved surface, but attention should be paid to avoid overpressure during backwashing to prevent the membrane from damaging or destroying the sealing and bonding surface.
2.The chemical cleaning method of uf filter membrane
When the membrane environment is seriously polluted and the diffusion coefficient cannot be repaired by physical methods, it must be cleaned with an organic chemical cleaning agent, and chemical changes are made with chemicals and impurities on the membrane surface to achieve the purpose of cleaning the membrane. There are certain standards when using chemicals, one is that they cannot chemically change with other materials of the membrane and parts, and the other is the drugs used to prevent secondary pollution. Below are a few details
①. Acid solution cleaning: Common aqueous solutions include sulfuric acid, sodium citrate, hydrochloric acid, etc. The pH of the prepared aqueous solution is 2~3, and the circulatory system is cleaned or soaked for 0.5h~1h, and then the circulatory system is cleaned to remove inorganic impurities. Works well.
②. Alkaline solution cleaning: Common alkalis mainly include sodium hydroxide solution, ferric chloride solution, potassium carbonate, etc. The pH value of the alkaline solution also depends on the type of membrane material, generally around pH=10~12. The circulatory system is actually cleaned or cleaned after soaking for 0.5h~1h, which can reasonably remove impurities and vegetable oils.
③. Reductant cleaning agent: Use 1%~3% H2O2, 500~1000mg/LNaClO and other solutions to clean the ultrafiltration membrane, which can remove stains and eliminate bacteria. H2O2 and NaClO are commonly used pesticides.
④. Add enzyme detergent: such as 0.5%~1.5% pepsin, protease, etc., to reasonably remove the chemical substances in the environment polluted by protein, sugar and vegetable oil.
The two cleaning methods of uf membrane filter have been described in detail above. It is recommended that all customers clean the runningro uf membrane on time in accordance with the standards of reducing operating costs and maintaining the life of mechanical equipment to prevent excess damage and confusion after long-term use.