A high-quality zeolite T membrane was prepared in only 6 h using a fluoride-mediated gel with NaF/SiO(2) ratio of 0.5 on mullite tubes seeded with nanosized zeolite T. The (19)F MAS NMR evidence shows that fluorine anion presents in channels as counter ion of cations. Zeolite T membranes synthesized in fluoride media displayed the high flux values of 4.43 and 3.64 kg m(-2) h(-1) with high separation factors of 8200 and 2900 toward 10 wt % water/isopropanol and 10 wt % water/ethanol mixtures at 348 K, respectively.