Synthesis of Hydrophilic Acid-resistant Ge-ZSM-5 Membranes via Secondary Growth Method Using Silicalite-1 Zeolite as Seeds

Hydrophilic acid-resistant Ge-ZSM-5 membranes were synthesized via secondary growth method on porous a-A1203 substrates with Silicalite-1 zeolite as seeds. The membranes were characterized by means of 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 solution by pervaporation. The results show that membranes fabricated by the conventional secondary growth method have a high flux, but the selectivity of them is rather limited. Preheating the secondary synthesis sol and using the supernatant as the secondary synthesis sol for membrane fabrication were found to be ef- fective to lower the concentration of the nutrient to constrain re-nucleation, at the same time, lower the A1 content in the membranes. The membrane obtained exhibited improved separation performance with a separation factor of 83 at a flux of 0.67 kg.rn-2.h-1 at 353 K for a feed concentration of 98% acetic acid solution.