Ultrathin Graphene Oxide Nanoribbon Networks as Architects of Enhanced Performance in Polyamide-Based Nanofiltration Membranes

Abstract

Customized architecture and chemistry play a pivotal role in conferring exceptional permeability and selectivity to polyamide (PA) membranes for desalination and ionic separation. Herein, a new interfacial polymerization (IP) template, the ultrathin graphene oxide nanoribbon (GONR) networks, is developed to meet the need for minimizing the funnel effect and mediating the IP reaction toward a highly permeable and selective membrane. The coated GONR template efficiently represents the gutter layer role and regulates the adsorption and transport of amine monomers at the GONR interface, which is studied by molecular simulation as well. The structure, electrostatic interaction, capillary rise, and nanoconfinement of the IP template are manipulated by different GONR loadings to optimize the membrane structure. The optimized GONR loading at 0.02 g m⁻² results in a hybrid layered GONR/PA-thin-film-composite nanofiltration membrane with nanostrip crumpled structure beyond the PA context, ultrathin 15 nm PA nanofilm, 80% cross-linking degree, and narrow pore size distribution. The membrane passes the upper bound trade-off with a permeance of 21.3 L m⁻² h⁻¹ bar⁻¹ and a remarkable rejection of 98% for Na₂SO₄. This research offers a fresh perspective on comprehensively understanding the role of the IP template in creating a desired membrane for efficient desalination and ionic separation.