NOVELTY - A membrane structure comprises a tubular porous ceramic monolith (10) having tubular conduits (16) each having an internal diameter of 5-9 mm formed within the monolith with a zeolite membrane formed on the internal surface of the conduits. There are four conduits and the monolith is longer than 600 mm or there are five or more conduits. The wall thickness between conduits is 2 mm. The wall thickness between the conduits and the outer surface of the monolith is 4 mm. The monolith is of length 1200 mm and has an outer diameter of 20-50 mm.    USE - The membrane structure is used for removing water from an organic liquid (ethanol or butanol) containing water or purifying water containing salt or other contaminants (claimed). It can also be used for membrane pervaporation systems for drying bio-ethanol to produce the new greener fuel-bio-ethanol.    ADVANTAGE - The structure facilitates the rapid and non labor-intensive preconditioning of multi-conduit monoliths for subsequent membrane deposition. The membrane exhibits excellent solvent resistance. High temperature resistance of the membrane enables its use at higher temperatures yielding higher permeate fluxes and reduce membrane area or shorter drying times. Due to high membrane selectivity, the permeate produced consists of high purity water that can be recycled or discharged without further treatment.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a method of treating porous substrates having tubular conduits to conditions the substrate for membrane formation, comprising forming an aqueous suspension of zeolite particles, and passing the suspension through the tubular conduits and out through the walls of the tubular conduits to deposit a layer of zeolite particles on the inner surfaces of the tubular conduits;    (2) a module comprising membrane structures and sealing members; and    (3) a method for forming zeolite membranes in internal surfaces of conduits in a cylindrical porous ceramic monolith comprising flowing an aqueous pre-treatment liquid including a zeolite initiating agent into the conduits, causing at least part of a carrier liquid component of the treatment liquid to flow into and through the body of the monolith to the exterior, and causing zeolite crystals to be deposited in the porous internal surfaces of the conduits.    The zeolite membrane is treated with silicic acid and/or polysilicic acid for reduction in membrane defects and pinholes.    DESCRIPTION OF DRAWING(S) - The drawing is a diagrammatic perspective view of a porous monolith.    Porous ceramic monolith (10)    End faces of monolith (12)    Glazed regions (14)    Conduits (16)