Two-dimensional, graphene-based materials, such as GO (structure shown in Figure 1), have attracted great attention as a new membrane building block, primarily owing to their potential to make ultimate membranes with the thinnest thickness and thus provide the highest permeance for effective sieving, assuming comparable porosity to conventional membranes and uniform molecular-sized pores. Great challenge, however, exists to fabricate large area, ultrathin GO membranes that have negligible undesired transport pathways, such as grain boundaries, tears, cracks, etc. Our research in this direction is focused on fabrication, nanostructure clarification, and separation study of ultrathin, GO-based membranes.
Under the support by NSF Career Award and DOE/NETL, we obtained the following key results and reported them in peer-reviewed journals:
· We demonstrated the feasibility of using a facile vacuum filtration process to fabricate ultrathin GO membranes (thickness of ~ 1.8 nm) for highly selective H2 separation.
· We developed a printing process to deposit ultrathin GO membranes on polymeric substrate.
· Self-assembly was found to be an effective way of forming high flux and high selectivity GO membranes for water purification.
· GO membranes functionalized with amines were highly efficient for CO2 capture.
Currently we are working on nominal single-layered GO membranes with tunable pores (3-10 nm) for protein separation, crosslinked GO membranes for molecular separation of hydrocarbons and extraction of organics from water, and scalable process for depositing ultrathin GO membranes for water purification. A UK company, G2O Water Technologies LLC, is commercializing our GO membranes for water purification. In the future work, we will further understand the GO-based membrane nanostructures and fundamental transport mechanisms and identify promising membrane structures and scalable membrane fabrication processes for commercialization.