Highly intergrown mordenite membranes were rapidly prepared on seeded aluminum supports by microwave-assisted synthesis. Both the thicknesses of the zeolite layer and the sizes of the zeolite crystals of the mordenite membranes were highly dependent on the synthesis time. With a SiO2:0.08Al(2)O(3):0.2Na(2)O:0.1NaF:35H(2)O precursor synthesis gel, a compact and 0.75 rho m thick mordenite crystal layer was successfully prepared on the aluminum support at 170 degrees C for 3 h. The as-synthesized mordenite membrane exhibited excellent water perm-selectivity and long-term stability for dehydration of alcohol/water, acetic acid/water, and acetic acid/ethanol/water/(e)thyl ester mixtures by pervaporation. For dehydration of 90 wt % acetic acid/water solution, the corresponding flux and separation factor (water over acetic acid) of the membrane remained at 0.44 kg center dot m(-2)center dot h(-1) and 2300, respectively, at 75 degrees C even after 59 days of immersion.