With the promotion of environmental protection, water treatment equipment is widely used in all walks of life. During the operation of water treatment equipment, there are always various problems. Then, why does the reverse osmosis membrane function of water treatment equipment decline? How to deal with it?
The main reason for the decline of RO membrane function is that the membrane surface is polluted, such as fouling of surface deionization water treatment equipment, blockage of membrane surface, or physical and chemical changes of membrane itself. Physical changes are mainly due to the compaction effect of the coating water treatment equipment, which results in the decrease of membrane permeability; chemical changes are mainly due to the fluctuation of pH value, such as hydrolysis of cellulose acetate membrane; free chlorine also deteriorates the function of aromatic polyamide membrane. The fouling and blocking of reverse osmosis membranes are mainly caused by the accumulation of membrane surface and the growth of microorganisms. In the meantime, microorganisms not only block the membrane, but also have a corrosive effect on cellulose acetate. Therefore, it is necessary to adhere to a certain amount of residual chlorine in the membrane, but the residual chlorine of glass tank membrane cleaning equipment is too high, which will cause the decline of membrane function. Therefore, the residual chlorine should be 0.1-0.5 mg/L before fibrin acetate membrane, while the residual chlorine before aromatic polyamide membrane is less than 0.1 mg/L.
Cleaning treatment of reverse osmosis membranes is a thorough and complicated operation. At present, the quality of domestic membranes is not high enough and the membranes are easily damaged after repeated cleaning. In order to alleviate the cleaning operation, it is necessary to do a good job of pretreatment, strictly control the water quality, otherwise, "the future is endless".
The treatment method is to use 0.1% formaldehyde solution or 100 mg/L concentration of benzalkonium bromide to clean for at least 1 hour. Contaminated membranes should be cleaned with 2% ammonium citrate solution (pH=4-8), or with sodium bisulfite, sodium hexametaphosphate, dilute hydrochloric acid to avoid scaling of manganese, iron and carbonate. Organic substances are sometimes cleaned with enzymatic detergents. The cleaning pressure is controlled at 0.34-0.98 MPa (3.5-10 kgf/cm2), and the cleaning flow rate is 2-3 times that of the water treatment.
Author: Hangzhou Water Shield Technology Co., Ltd.
Website: http://www.zjhzsd.com
Key words: deionized water treatment equipment, coating water treatment equipment, glass tank membrane cleaning water equipment
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