The cause of the ultrafiltration membrane pollution harm and treatment method

A, the analysis of the causes of ultrafiltration membrane fouling

ultrafiltration membrane pollution is mainly lining material and chemical properties of the solute in the solution, membrane and solute interactions and the question of the consequences. Whether in the applications, the object of the separation by ultrafiltration process are dissolved or glue posture of big molecular weight of organic matter, when these materials and made of synthetic organic polymer materials of ultrafiltration membrane contact, between the solute and the membrane material will produce relatively strong adhesion, adsorption and combined with the tendency of which in adsorption dirt layer is formed on the membrane surface, cause the pollution of membrane. In addition, the membrane pollution include material liquid in the deposit of suspended solids on the membrane surface.

once the ultrafiltration membrane contamination, will cause the permeable membrane flux decline, and the flux of attenuation is usually not reversible, so it can lead to ultrafiltration process could not be a long time of stable operation, affect the efficiency of ultrafiltration into full play.

2, membrane pollution control measures are:

(1) through the effective cleaning membrane permeable performance restoration;

2) filter, coagulation sedimentation and measures of material liquid pretreatment;

(3) increase the membrane surface tangential velocity, reduce the boundary layer thickness, enhance mass transfer coefficient;

(4) choose appropriate operating pressure, avoid increasing precipitation layer thickness and density;

(5) research and development has the optimal pollution resistance of the membrane material

3, how to choose the ultrafiltration membrane cleaning

membrane cleaning effect under the specified operating conditions, the service life of ultrafiltration membrane is usually 12 to 18 months. Ultrafiltration process due to the interaction between solute and ultrafiltration membrane, can make accumulation layer membrane surface adsorption and membrane pollution, thus must be conducted on membrane cleaning regularly, to restore and maintain the water flux of membrane, prolonging the life of the membrane. The cleaning methods of membrane water washing, washing and mechanical cleaning methods such as, usually should be dealt with according to the film and the properties of the material liquid and the form of a membrane module for sure.

the ultrafiltration process of macromolecular processing object and colloidal solution, membrane easily polluted and ultrafiltration membrane needs regular cleaning. The formula of general cleaning solution according to the nature of the membrane and to determine the kinds of pollutants. For example with lotion on protein, polysaccharide and the colloid pollution has good cleaning effect; Emulsified oil wastewater, such as machining enterprise of coolant, sheep & euml; Washing wastewater processing industry, adopt more surface active agent and alkaline aqueous solution on the membrane surface cleaning; Latex pollution often adopts low molecular alcohol and butanone; Fiber oil pollution in addition to clean with warm water, also regularly use industrial alcohol cleaning; Treatment of sewage by membrane process often in sodium hypochlorite solution, etc. If there is a ready-made material, its cleaning formula and the cycle should be determined by test.