In situ formation of porous organic polymer-based thin polyester membranes for loose nanofiltration

Porous organic polymers (POPs) hold considerable promise for developing porous membranes with fast and efficient molecular separation because of their well-structured pores, robust organic backbone, and adjustable chemical functionalities. However, preparing membranes from POPs via conventional solvent casting method is difficult because of the insolubility of the majority of POPs in most solvents. Here, for the first time, polyester membranes were in situ fabricated using hydroxyl-containing POP on a porous substrate via interfacial polymerization. The abundant hydroxyl groups within POP enabled them to be crosslinked with trimesoyl chloride (TMC) at the water/hexane interface at a mild temperature (40°C), thus forming a defect-free, continuous active layer. The superb intrinsic porosity of POP as well as their hydrophilic nature promoted a high water permeability of 31.28 L m−2 h−1 bar−1. Importantly, the as-fabricated polyester membranes exhibited high dye rejection (>95%), low salt retention (25.53% for Na2SO4), rendering them highly competitive for dye/salt fractionation. Notably, the membranes demonstrated good chlorine resistance and antifouling properties. This facile and cost-effective approach provides a useful guideline for assembling POP into continuous membranes with great potential for textile effluent treatment. [Display omitted] •Hydroxyl porous organic polymer based polyester membrane was firstly in situ synthesized via interfacial polymerization.•The membranes showed high dye rejections and low salt retentions, rendering them highly competitive for dye/salt separation.•The POP-based membranes demonstrated superior chlorine resistance and antifouling property.