Preparation of Holey Graphene Oxide-Modified Polyamide Composite Organic Solvent Nanofiltration Membranes

Coal thermal dissolution extraction is key for efficient conversion/utilization of low-rank coal, but its industrialization is limited by poor extraction product separation. However, commercial thin-film composite (TFC) polyamide membranes swell in organic solvents, compromising separation accuracy. To solve this, this study incorporated holey graphene oxide (HGO) into interfacial polymerization. HGO-modified polyamide composite membranes were prepared, and their feasibility in OSN was explored. HGO’s amphiphilicity and porous structure enhanced piperazine monomer diffusion kinetics/uniformity, improved polymerization cross-linking, and built an interpenetrating network with polyamide chains to inhibit membrane swelling in polar solvents. Experiments demonstrated that the modified membrane exhibited better structural stability in methanol and excellent small-molecule sieving in methanol systems simulating low-rank coal thermal dissolution extracts. This study fills the gap in HGO for organic OSN membranes, offers new insights for high-efficiency OSN membrane preparation, and facilitates the efficient separation of coal extraction products.