The Preparation Method Devolopment And Anti-Biofouling Property Research Of Nanomaterials Mixed Matrix Membrane

Biological pollution and germs osmosis is the two main obstacles on the membrane separation water treatment. Membrane fouling not only reduces the penetration of membrane and the life span of the film, but also increases the energy consumption. In order to effectively remove bacteria and improve the anti-biofouling property of membrane, we do some research about this program. This paper will study a kind of mixed matrix membrane that contains anti-biofouling property under the condition of low voltage operation.Firstly we will prepare the casting solution that contains the polymer of polysulfone, the solvent of N-methyl pyrrolidone and the additive of polyvinylpyrrolidone. Secondly we will prepare the ultrafiltration flat membrane by using the method of L-S phase inversion. Thirdly we will respectively investigate the influence about polysulfone concentration, polyvinylpyrrolidone concentration and coagulation bath temperature on the properties of ultrafiltration membrane structure. We put the Water flux and membrane resistance as evaluation index, and then we study the high flux of ultrafiltration membrane. The best optimized conditions of ultrafiltration membrane are as follows:the mass fraction of polysulfone is15%, the mass fraction concentration of polyvinylpyrrolidone is8.0%, the temperature of coagulation water bath is60癈.Nanofiltration membranes are prepared on the basis of the best ultrafiltration flat membrane by the method of interfacial polymerization. Then we do some intercept experiment of glucose neutral molecules through membrane performance evaluation device. We put the intercept rate of glucose as evaluation standard and explore the optimum process conditions of preparing high performance of nanofiltration membrane. The best optimized conditions of nanofiltration membrane are as follows: the mass fraction concentration of piperazine is1.0%, the trimesoyl chloride is0.2%, and interfacial polymerization time is for30s.Then we do some desalination experiment of best nanofiltration membrane about salt solution (NaCl and Na2SO4, MgSO4) of different valence state by using membrane performance evaluation device. After that we investigate the desalination performance of electrolyte inorganic salt of the best nanofiltration membrane and study the conditions that have impacts on the interception performance of the best nanofiltration. These conditions are about concentration of the inorganic salt solution and operating pressure and so on. We prepare the nanometer materials mixed matrix membrane by the three different approaches of particle embedment that involves the dispersion of four kinds of nanoparticles, the four kinds of nanoparticles are zeolite, hydrated aluminum oxide nanoparticles, carbon nanotubes and nano-silver. The three embedment ways are as follows:the first way is In situ implantation method, that is to say, we put the nanoparticles in the water phase during membrane precipitationin; the second method is that we put the nanoparticles into the inorganic phase solution; the third method is that we put nanoparticles into the organic phase solution. By changing the concentration of nanoparticles in solution, we prepare different composite membranes that contain nanoparticles. In order to determine the good nanoparticles of different implant ways and the best concentration, we observe the microscopic structure of the composite membranes by scanning electron microscope. The best concentrations of In situ implantation method are0.05%Al2O3and0.05%zeolite; the best concentrations of the sencond way which nanoparticles in the inorganic phase solution are0.1%Al2O3and0.05%zeolite; the best concentrations of the third way that nanoparticles in the organic phase in the solution are0.05%zeolite and0.05%silver nanoparticles.The anti-biofouling property of nanoparticles composite membrane is evaluated using the attachment potential of Escherichia coli (E. coli.) on membrane surface. The loss of viability by nanoparticles of E. Coli on membrane surface is initially obtained by a fluorescent microscope. We ultimately study the best mixed matrix membrane. The best membrane is UF membrane with zeolite in situ implantation method. The best membrane is NF membrane with zeolite that the zeolite in the inorganic phase solution. The best membrane is NF membrane with nano-silver that the silver in the organic phase solution.