| 摘要 |
PURPOSE:To recover the separating power, esp. a water-permeating speed, of a semipermeable membrane composed of polysulfone, sulfonated polysulfone or the like, by treating the semipermeable membrane whose separating power is lowered at pH above 10 and a temp. above 55 deg.C with an aqueous surfactant solution. CONSTITUTION:A semipermeable membrane formed from a polymer selected from polysulfone, sulfonated polysulfone, polyether sulfone, poly(vinylidene fluoride), polyacrylonitrile and chlorinated poly(vinylidene chloride) whose separating power is deteriorated by treating alkali pulp mill waste liquor with it is treated under the condition of pH above 10 and a temp. above 55 deg.C by using an aqueous solution contg. 0.001-10wt% a surfactant, to recover the separating power. Said treatment of the semipermeable membrane may be performed, e.g. by detaching the membrane from a module and dipping it in the aqueous surfactant solution. |
