Facile Fabrication of High Performance Nanofiltration Membranes by Using Molecular Coordination Complexes as Pore-Forming Agents

Nanofiltration (NF) is widely used in water treatment; however, the fabrication of NF membranes with high permeability and selectivity still remain a challenge. Here, we propose a facile and feasible approach to design and prepare nanoporous polymeric membranes (NPMs) by using soluble molecular coordination complexes as pore-forming agents for the removal of dyes from water. Enhanced porosity and tuned pore sizes of the membranes were achieved by using several selected coordination complexes with different compositions and structures. The resulting membranes display high permeance without compromising rejection compared with corresponding pristine membranes. Particularly, one of membranes, with tBu-MOP acting as the pore-forming agent, shows an optimal separation performance of the water permeance over 209 L/(m2·h·MPa) and a rejection about 98% toward both methyl blue (MB) and eriochrome black T (EBT). This permeance is 4.5-fold higher than that in the pristine membrane fabricated without using any pore-forming agent. This method is expected to extend to the fabrication of other polymeric membranes with required pore properties by selecting suitable coordination complexes as pore-forming agents for different separation applications.