In situ growth of α-Fe2O3 on Al2O3/YSZ hollow fiber membrane for oily wastewater

This work focused on in situ growth of α-Fe2O3 on an asymmetric Al2O3/YSZ hollow fiber via hydrothermal route. An asymmetric Al2O3/YSZ hollow fiber composite was prepared using the dry–wet phase inversion method and sintering process. The pristine hollow fiber and hollow fiber with α-Fe2O3 were systematically characterized using FESEM. The separation performance of the membranes was determined using the fluxes of both pure water and synthetic oily wastewater and membrane rejection. The FESEM images show more α-Fe2O3 particles grew and deposited on the hollow fiber with at increasing iron (Fe) concentration. The flux of the hollow fiber with α-Fe2O3 was higher compared to that of the pristine hollow fiber (1003 and 1148–1370 L∙m−2∙h−1, respectively). As for oily wastewater separation, the flux declined when the Fe concentration was increased from 0.05 to 0.5 M. However, an improvement in oil rejection up to 95% was obtained. Under visible light assisted filtration, fluxes and rejections of oil emulsion increased, which indicates that the α-Fe2O3 growth on top of the hollow fiber is prone to activate the photocatalytic activity for self-cleaning properties. Hence, the α-Fe2O3 supported Al2O3/YSZ hollow fiber can act as both separation membrane and photocatalytic membrane.