Constructing high-efficiency facilitated transport pathways via embedding heterostructured Ag+@MOF/GO laminates into membranes for pervaporative desulfurization

Abstract

Mimicking the efficient facilitated transport features of carrier proteins in cytomembranes, constructing facilitated transport pathways in synthetic membranes to achieve the desired performance for task-specific molecules has become attractive. Herein, heterostructured laminates (UGO) were created through in-situ growth of amine-functionalized zirconium-based metal-organic frameworks (UiO) on graphene oxide (GO) nanosheets, and subsequently used as supports to immobilize Ag+. The as-prepared Ag+@UGO were incorporated into poly (ether-block-amide) (Pebax) matrix to fabricate facilitated transport membranes for pervaporative desulfurization. Densely packed UiO on GO nanosheets increase the inter-particles connectivity of the molecular transport channels and reduce the mass transport resistance, intensifying the permeability. Meanwhile, the uniform immobilization of Ag+ can reversibly interact with thiophene via π-complexation reaction and form continuous facilitated transport pathways, significantly enhancing the selectivity. Accordingly, the resultant membrane acquires separation performance with an optimum permeation flux of 23.40 kg/(m2 h) and enrichment factor of 7.12, achieving 52% and 57% higher than the pristine membrane. This study extends strategies to design high-performance hybrid membranes with facilitated transport mechanism through the well-designed heterostructures as supports to immobilize carriers for molecular separations.