Abstract: The invention features porous substrates or supports fabricated from titania powder(s) having mean particle size of at least 7 .mu.m. The titania substrates are useful for supporting porous membranes for separation and filtration processes. The titania powders provide supports with mean pore sizes in the approximate range of 3 to 15 .mu.m, a sharp or narrow pore size distribution, total Hg porosities of at least about 30%, and MOR strengths of 50 up to 280 or more Kg/cm.sup.2. A combination of several different titania powders produced the best results. Titania membranes can be formed on the titania supports.