As we all know, once the ro uf membrane is polluted, the permeable flux of the membrane will decrease. The attenuation coefficient of this flux is generally irreversible, which will cause the entire process of the uf membrane use to be unable to carry out long-term stable practical operation, which will endanger Make full use of it efficiently.
1. Reasons for the pollution of ro uf membrane.
When the working pressure is constant, the ultrafiltration membrane flux decreases with the increase of the filtration time period; when the total flow rate is constant, the transmembrane pressure difference increases continuously with the increase of the filtration time period. The primary factor causing this problem is that during the entire process of the uf membrane use, polluting chemicals such as particles and colloidal solutions in the water are intercepted and accumulated on the membrane surface or in the pores, thereby causing adverse hazards to the entire process.
2. The method of controlling the pollution of ro uf membrane.
a. The water resistance of the film can be effectively cleaned and repaired;
b. Take measures such as filtration, coagulation and sedimentation to prepare the material and liquid;
c. Increase the radial velocity of the membrane surface, reduce the thickness of the boundary layer, and increase the convective heat transfer index;
d. Choose an appropriate working pressure to prevent the relative density and thickness of the deposited layer from increasing;
e. New product research and development of membrane raw materials with good anti-pollution properties.
3.The classification of ro uf membrane pollution.
According to the current understanding of the pollution of the ro uf membrane, it can be divided into three categories: organic pollution, inorganic compound pollution and microbial strain pollution.
Organic pollution is mainly membrane pollution caused by various organic substances in the water, which is manifested as the fouling layer on the membrane surface or the blockage of the membrane pores.
Inorganic pollution is mainly membrane pollution caused by floating chemicals. It is mainly done in two ways. One is the accumulation of inorganic particles and organic matter on the membrane surface and in the membrane pores; second, the continuous accumulation of particulate chemical substances is likely to produce a slowly rising frictional resistance.
Microbial strain pollution is mainly membrane pollution caused by microorganisms and their secretions. Studies have shown that bacteria can adhere to the surface of the membrane to produce a biofilm system. This biofilm system is biologically active and endangers the water permeability of hydroelectric power generation.