Prearation Of New Style Organic-Inorganic Hybrid Charged Nanofiltration Membranes

For the past few years, more and more articles about charged nanofiltration membranes and ordered mesoporous materials were reported in worldwide. Charged nanofiltration membranes get sieving effect and electric charge effect by their features of nanometer diameter holes and charged surface. Mesoporous materials have characteristics of ordered pore structures and narrow pore size distribution. The mesoporous molecular sieve which we are talking about in this article is a new-type of mesoporous material. It not only has characteristics of Mesoporous materials'but also has the specific features of electric charged in inner wall of the pore and charged free on outside. Once this mesoporous molecular sieve is applied to preparation of charged nanofiltration membranes, the problem of congregating of inorganic charged particulates in casting solution is solved. The mesoporous molecular sieve's features of ordered pore structure and charged inner wall can also improve the abilities of the charged nanofiltration membranes in separating small charged organic molecules.1) An ordered mesoporous materials was synthesized with N-trimethoxy-lsilylpropyl-N,N,N-trimethylammonium chloride (TSPMNC) and tertme thox-ylsiloxane(TEOS) as raw meterials and dodecyl sulfate sodium salt(SDS) as template. The product was characterized by XRD, TGA,BET,SEM, XPS,TEM,FT-IR methods. The results indicated that the product presented the hexagonal pore structure of MCM-41, and the pore size was 3.5nm. The product contained 1.41mmol/g of the quaternary ammonium groups.2) A new type of organic/inorganic hybrid positively charged nanofiltration membrane was made by the molecular sieve and silastic. These membranes can separate positively charged dye molecules well. The formulas and crafts to build the membranes were quested by comparing the separation performance of the membranes which were produced by different ways. The membrane rejection for different dyes of 300-700Da lied in 40%-99%. The result showed that some elements can enhanced electric charge effect of the membranes, and firstly increasing the proportion of the mesoporous molecular sieve in casting solution, secondly decreasing the pore size or making the pore structure more ordered of the mesoporous molecular sieve.