Hydrophilic acid-resistant Ge-ZSM-5 membranes were synthesized by the secondary growth method on porous α-Al2O3 substrates with Silicalite-1 zeolite as seeds.The membranes were characterized using scanning electron microscopy,X-ray diffraction and energy dispersive X-ray spectrometer to look into the microstructures and element contents of the membranes.The separation performance of the membranes was investigated for separating water from acetic acid by pervaporation.It was shown that membranes fabricated using the conventional secondary growth method had a high flux but the selectivity is rather limited.By preheating of the secondary synthesis sol and using the supernatant as the secondary synthesis sol for membrane fabrication was found to be effective to lower the concentration of the nutrient to constrain re-nucleation,at the same time,lower the A1 content in the membranes.The membrane so obtained exhibited improved separation performance;a separation factor of 83 at a flux of 0.67 kg/cm2·h at 353 K was achievedration for a feed concentration of 98 wt% acetic acid.