Shear-aligned graphene oxide laminate/Pebax ultrathin composite hollow fiber membranes using a facile dip-coating approach

Abstract

Graphene oxide (GO) has been considered as a promising candidate for molecular separation because of its capability to form highly efficient gas flow intergalleries. However, a major challenge is the lack of a facile, scalable, low-cost membrane fabrication approach, especially for the hollow fiber composite membrane with a thin selective layer. By using a facile dip-coating technique, we prepared a shear-aligned GO/Pebax composite hollow fiber membrane on a porous polymeric support. The incorporation of the aligned GO laminates significantly improved the original Pebax (polyethylene oxide–polyamide block copolymer) membrane permeance without compromising the CO₂/N₂ selectivity, and the composite membrane had good operational stability and enhanced mechanical strength. We further investigated the formation mechanism of the shear-aligned GO structure and discovered that the control of the withdrawal speed and liquid film thickness was a key factor. This dip-coating technique offers significant opportunities to exploit the GO-based membrane for industrial CO₂ capture.