In situ hydrothermal growth of Zeolite-A membrane on polysulfone hollow fibers

Abstract

Zeolite-A hollow-fiber membranes with a high surface area are explored to address the present demands of high-productivity bioethanol manufacturing. Herein, we prepared Zeolite-A membranes on polymeric hollow-fiber support via double hydrothermal crystallization. The first hydrothermal crystallization from the solution yielded zeolite A crystals anchored on the polysulfone support. This transformation of the hollow fiber's skin layer into an organic-inorganic interface layer, as observed through SEM-EDX elemental analysis. This interface layer with penetrated Zeolite-A provides nucleation sites for further Zeolite-A membrane formation during the second hydrothermal crystallization and simultaneously enhanced interphase adhesion of Zeolite-A with the polymer support. The duration of the first and second cycles of hydrothermal crystallization was systematically studied to obtain continuous, crack-free, and pure Zeolite-A membranes on polysulfone hollow-fiber support. The membrane exhibited fluxes of 3.8 and 9.75 kg m−2 h−1 at 25 °C and 75 °C, respectively, with >99.9 wt% water separated through pervaporation of the 90/10 wt % ethanol/water mixture.