| 摘要 |
PURPOSE:To secture a practical water transmitting speed even to a colored aqueous solution with high salt concn. and to also remove a coloring component with a relatively low MW with high efficincy, by using a semipermeable membrane having a sulfonic acid group. CONSTITUTION:Sulfonated polyaryl ether, which was obtained by sulfonating polyaryl ether comprising a repeating unit I (wherein R is -CO- or -SO2-) or a linear polyaryl ether copolymer consisting of the repeating unit I and a repeating unit II (wherein R' is a C-C bond or a divalent group containing -CO- or -SO2-), is dissolved in ethylene glycol monomethyl ether and a low volatile org. compound such as lactic acid is added to the resulting solution as an additive to prepare a film forming solution which is, in turn, applied to a support membrane such as a polysulfone dry ultrafiltration membrane and the solvent is subsequently evaporated to obtain a composite semipermeable membrane having a membrane like skin layer. The discoloration of a colored aqueous solution with high salt concn. for example, soy sauce is performed by using this membrane. |
