Scaling-up CO2-selective graphene oxide membranes via sequential coating with gelated graphene oxide and polyethyleneimine for CO2 separation

In our ongoing efforts to mitigate the rapidly increasing carbon dioxide (CO2) emission, graphene oxide (GO) membranes are expected to be the next generation of CO2 separation membranes. However, existing fabrication methods lack the scalability required for commercial production of laminar GO membranes. To address this challenge, we developed a scaled-up laminar GO membrane by coating a thin laminar GO film onto a commercial ultrafiltration membrane using a blade-casting technique in combination with an ion-crosslinked GO hydrogel. The as-prepared GO membrane was then surface-modified with polyethyleneimine to imbue a unique CO2-selectivity for handling humidified CO2-containing feed gases. Resultantly, this approach yielded a GO-based membrane with a scaled-up surface area of close to 0.1 m(2). The membrane demonstrated good uniformity and performances at CO2/CH4 and CO2/N-2 selectivities of 22.3 and 34.4 in wet conditions, respectively. Furthermore, the membrane also showed long-term stability for about 100 hours. Overall, this study showcases the potential of our approach for producing scalable GO-based membranes and underscores the effectiveness of the CO2-selective membrane for CO2 separation.