Facile preparation of nanochannel membrane based on polydopamine modified porous organic polymer nanoparticles for high-efficient dye desalination

Nanochannel membranes derived from porous nanomaterials are crucial for driving the development of advanced desalination and water treatment membranes. However, the practical application of polymer nanochannel membranes is halted by the tedious and complicated preparation and the lack of stability in aqueous service process. In this work, we synthesized a novel type of polydopamine modified imidazolium containing porous organic polymer nanoparticles (PDA@POP), which has good water dispersibility and interface adhesion capability. The PDA@POP aqueous dispersion solution was dip coated on the polysulfone ultrafiltration supporting layer, and the nanocoating was further crosslinked with 1,3,5-Benzenetricarboxylic chloride. The appropriate surface modification of POP nanoparticles with PDA enhances the interfacial interaction and maintains effective-aperture structure, leading to stiff and continuous nanochannels facilitating the water molecules and salt ions quickly transporting through the PDA@POPM membrane. As such, both the water permeability (similar to 57.0 L center dot m(-2)center dot h(-1)center dot bar(-1)) and dye/salt selectivity (>24) of PDA@POPM are improved 5-10 times higher than that of conventional polymer nanofiltration membranes. Meanwhile, the membrane exhibits good stability and anti-fouling property in long-term dye desalination process. This work provides a convenient and universal strategy to design and manufacture nanochannel membranes with high separation performance.