DEVELOPMENT OF CROSS-LINKED AROMATIC POLYAMIDE COMPOSITE REVERSE-OSMOSIS MEMBRANE

We have found that the cross-linked fully aromatic polyamide reverse osmosis membrane composed of 1,3,5-triaminobenzene has high separation performance and high durability. High cross-linking density contributes to high salt rejection (> 99.5%) and high durability. We also developed the new synthetic method of 1,3,5-triaminobenzene suitable for high performance membrane. We could obtain the high purity 1,3,5-triaminobenzene by purification of 1,3-diamino-5-nitrobenzene and reduction in the presence of Pd/C catalyst. We have newly developed the high flux type membrane fit for brackish water softening, the high salt rejection type one used in ultrapure water production and the two stage reverse osmosis membrane. High flux membrane could be achieved by introducing a hydrophilic group to the membrane materials at in-situ interfacial polycondensation. High alt rejection membrane was attained by reordering of polymer chain by post-treatment. Two stage reverse osmosis membrane introduced tetraalkylammonium salt groups takes the place of the ion exchange tower. These membrane technology based on 1,3,5,-triaminobenzene is used especially for ultrapure water production, seawater desalination, trihalomethane separation and so on.