Editor's note: In order to improve the anti-fouling ability of the ultrafiltration membrane, people often modify the ultrapure water membrane material or the membrane surface for a certain physical system. So what are the recommended modification methods?
1. Membrane surface modification Chen et al. Used anionic surfactant to pretreat the ultrafiltration membrane during the ultrafiltration of protein, which reduced the flux attenuation caused by pollution. This is due to the addition of anti-ionic surfactants, which changes the electrostatic interaction between the protein and the membrane surface and reduces protein deposition. In the preparation of polysulfone ultrafiltration membranes, Hamza et al. Added different macromolecules as surface modifiers to the membrane liquid, prepared modified polysulfone ultrafiltration membranes by phase inversion method, and used them to treat O / W oily emulsion In wastewater, the results show that the modified polysulfone ultrafiltration membrane is superior to the unmodified membrane, and the resistance of the gel layer on the surface of the modified membrane is relatively small.
2. Developed composite separation membrane Faibish et al. Grafted vinylpyrrolidine on the surface of zirconia ceramic membrane to prepare ceramic-polymer (CSP) anti-pollution ultrafiltration membrane, the membrane pore size was reduced by 25% to Twenty-eight, and used to treat O / W oily emulsion, improve the retention rate of emulsified oil, effectively reduce the deposition of pollutants on the membrane.
3. Preparation of blending film Blending is usually to overcome the deficiency of a material in a certain performance, and one or more substances are added to prepare a film with better comprehensive performance. The preparation of blended membranes is one of the hot topics of membrane science workers. Hao Jihua et al. Developed chloromethylated / quaternized ammonium sulfone and polyvinylidene fluoride blended ultrafiltration membranes, and used them in cathode electrophoresis paint ultrafiltration systems, which have good anti-pollution performance.
In addition, the anti-fouling ability of the ultrafiltration membrane can also be improved by enhancing the filtering operation, such as introducing gas a phase to slow down particle deposition, introducing electric field, ultrasonic field plus field to strengthen the filtering process, etc.
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