Patent ID: 6221247
Filing Date: 2001-04-24
Classification: B01D,C02F

Abstract:
A membrane module comprising a two-sided microporous membrane structure having passageways through the structure of a size effective to reject species suspended in an aqueous medium which species are of size in the range of about 0.01-10 .mu.m, said structure capable of passing a simulated graywater from a boiled mixture of a composition consisting of 435 mg detergent, 2 g laundry starch, 750 mg gelatin, 50 ml of 5% ammonium chloride solution, 15 ml of 1 M sodium chloride solution, 2.5 ml 1 M trisodium phosphate solution, 10 g canned dog food, 350 mg food shortening, 350 mg cooking oil per 5 L of tap water at a rate of at least 100 L/(m.sup.2 -h) continuously for longer than 150 hours when operated in a cross flow mode,in which said membrane structure comprises a microporous substrate having its microporous surfaces coated with a substance comprising a polymerized perfluoro-dioxole monomer having the following formula ##STR2##in which Y is either F or the perfluoroalkoxylic moiety --OR.sub.F of 1-5 carbon atoms and X.sub.1 and X.sub.2 are both CF.sub.3 when Y is F, and X.sub.1 and X.sub.2 are each independently selected from the group consisting of F and CF.sub.3 when Y is --OR.sub.F, andin which the substance has a surface energy less than that of tetrafluoroethylene homopolymer.