High performance zeolite NaA membranes synthesized on the inner surface of zeolite/PES-PI blend composite hollow fibers

Zeolite/polymer blend composite hollow fibers are prepared as a new type of zeolite membrane supports by the dry-wet phase inversion method. The spinning slurry is formed by mixing zeolite NaA crystals with miscible polyethersulfone-polyimide polymer blend. Zeolite NaA membranes are hydrothermally synthesized in the lumen side of the hollow fibers under dynamic conditions. Their properties are characterized by scanning electron microscopy, mechanical test, contact angle test and pervaporation. The effects of the N2 extrusion pressure and polyimide content on properties of the supports are investigated. Both of them limit the exchange rate between solvent and non-solvent during spinning process resulting in the supports with high mechanical properties. Zeolite membranes are thin and well intergrown with no macroscopic defects. The water flux is 10.6±0.4 kg m−2 h−1 with a separation factor of more than 10,000 in dehydration of a 90 wt% ethanol aqueous solution at 75 °C. The effect of hydrophobicity of the composite supports is discussed in the context of advantages of the supports.