Exploring the Potential of Nanoporous Single-Layer Graphene As a Next-Generation Membrane Material

Nanoporous graphene has potential as an ideal ultrathin membrane for high-flux, high-selectivity, chemically-resistant membrane separations. I will discuss our work on understanding mass transport and developing membranes that employ nanoporous single-layer graphene as the selective layer. Through controlled nucleation of defects via ion bombardment and oxidative etching, sub-nanometer pores are created in the otherwise impermeable graphene placed on a porous support. The resulting membranes exhibit selectivity between ions and between salt and small molecules. We also present strategies for the design of defect-tolerant membranes using centimeter-scale areas of single-layer graphene, which allows for measurement of water flux and solute rejection during filtration by forward osmosis. The membrane can reject multivalent ions and small molecules, and exhibits a permeance that is consistent with theoretical predictions. We also demonstrate that these membranes exhibit high mechanical strength and are able to withstand applied pressures up to 100 bar. These studies illustrate the feasibility and potential of single-layer nanoporous graphene membranes for nanofiltration, water purification, and other applications.