COMPOSITE DIAPHRAGM, COMPOSITE DIAPHRAGM MODULE AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To manufacture safe drinking water free from offensive odor, offensive taste and bubbles by minimizing the eluation amount of an anion surfactant from a membrane module even in the early stage of operation of a membrane separating device while the residual amount of the anion surfactant is suppressed at a low level. SOLUTION: In the composite diaphragm with the surface of a porous support coated with polyamide membrane, the amount of an anion surfactant extracted from the diaphragm is 9 g or less per 1 kg weight of the composite diaphragm. In addition, the composite diaphragm module is constituted of the composite diaphragm with the surface of the porous support coated with the polyamide membrane as a constituent element and suppresses the anion surfactant extracted from the composite diaphragm at a rate of 9 g or less per 1 kg weight of the composite diaphragm.