Processes for fabricating ceramic membranes include providing a porous substrate having at least one inner channel extending therethrough and having surfaces defined by porous walls, depositing a coating slurry on surfaces of the inner channel(s), and sintering. Sintering temperatures for the processes range from about 400 °C to 800 °C. Coating slurries for use in the processes include a boehmite sol and a colloidal suspension of porous alumina particles.