We prepared silica membranes using sol-gel techniques and explored the effects of postdeposition sintering, capillary stresses developed during drying, and surface derivatization of the membranes with titanium iso-propoxide. We observed that both partial sintering of membranes and development of larger-capillary stresses during membrane formation lead to consolidation of the membrane structure as evidenced by increased ideal separation factors, e.g. {alpha}CO{sub 2}2/CH{sub 4} > 250 over the temperature range of 160 to 220 C. Surface derivatization was also shown to be an effective tool to reduce the membrane pore size in an angstrom by angstrom fashion, resulting in comparable separation factors. What`s more, the altered pore surface chemistry of TiO{sub 2} derivatized membranes may lead to improved stability and impart catalytic properties to the membrane surface
