Dioxole coated membrane module for ultrafiltration or microfiltration of aqueous suspensions

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 μm, 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/(m2−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
• in which Y is either F or the perfluoroalkoxylic moiety —ORF of 1-5 carbon atoms and X1 and X2 are both CF3 when Y is F, and X1 and X2 are each independently selected from the group consisting of F and CF3 when Y is —ORF, and
• in which the substance has a surface energy less than that of tetrafluoroethylene homopolymer.