Study On Modification Of PVDF Membrane By Inorganic-organic Hybrid Materials And Its Antifouling Property

Membrane bioreactor(MBR) is better than traditional sewage treatment technology, because it has better effluent quality and stronger microbial intercept ability, but the occurrence of membrane pollution hinders the extensive application of MBR. The macromolecular organic matter and the accumulation of particles on the membrane surface block the film hole, thus causes the membrane fouling. However, hydrophilic membrane can form a layer of water on the membrane surface, it can effectively resist the pollutants adsorbed on surface, so as to slow down the film hole blockage and reduce the frequency of membrane pollution. And the growth of microorganisms will also aggravate the blocking on the surface of membrane, so the improvement of the sterilization performance of the membrane surface is also an important direction to promote the anti-pollution capacity of the modified membrane.This research mainly aims at changing the hydrophilic-hydrophobic property and promoting the ability of antibacterial adhesion of the membrane surface, drawing the organic-inorganic hybrid materials into the membrane surface by using the method of surface coating and surface grafting, introduced, using the method of quaternary ammonium in the membrane surface to graft functional group. Through these steps, we can promote the hydrophilicity of the membrane surface and its’ antibacterial adsorption ability. In our research, we use FTIR to analysis the functional groups’ situation on the membrane surface, we use the Contact Angle Meter to measure the hydrophilic-hydrophobic property of the membrane, we also do the water flux and BSA flux of the modified membrane to investigate the modified membrane’s ability of protein adsorption resistance; with the help of SEM, w e can also observe e. coil’s adhesion situation on the membrane surface, so as to study the modified membrane’s resistance ability of the microbial adhesion. Through these characterization methods, we can study the anti-fouling ability of the modified membrane.This study paper synthesis a Tetraploid Siloxane(4GTPS-2N) with active tertiary amino by the mean of organic synthesis, 4GTPS-2N belongs to the inorganic-organic nano hybrid material, itself has 12 ethyoxys, it can easyly do the hydrolytic condensation to form larger network polymers(POSS) so as to coat on the membrane surface, it can also conduct the membrane surface hydroxy reaction through surface grafting to access to the membrane surface. The tertiary amino groups in the material,which is easy to quaternary ammonium grafting functional groups, and quickly realize fictionalization.In our study, we graft the organic- inorganic hybrid materials to the membrane surface through surface coating and surface grafting. Comparison results shows that the surface coating method can get more grafted membrane coating, it can also get more quaternary ammonium on the membrane surface, which is benefit for the resistance of escherichia coli, the membrane’s hydrophilic property also get larger. However the incr easing amount of grafted resulted in the decrease of membrane flux, the water flux is smaller than coating by 50 L/(m2·h), BSA flux and protein resistance has a larger decline compared to the surface coating of membrane.Compared the modified membrane whi ch changed by the methyl iodide quaternary ammonium and 3-bromo propionate quaternary ammonium respectively, we can find that their surface contact angle are 10° and 40° lower than the original membrane, and the membrane changed by 3-bromo propionate quaternary ammonium is better than another in the aspect of water flux, BSA flux and flux recovery of the membrane and BSA flux are better than the effect of methyl iodide, except for the antibacterial adhesion ability.Through the above analysis, it can be see n that the surface coating method for membrane can get more graft volume and surface functional groups, and the antimicrobial adhesion effect is better too. And the surface coating method for membrane has better performance in the membrane flux experiments, its’ ability of protein adsorption resistance is stronger too. The membrane changed by the methyl iodide quaternary ammonium has higher sterilization performance, and the membrane changed by 3-bromo propionate quaternary ammonium has better hydrophilicity and stronger ability to resist the adsorption of protein.