A comprehensively fouling- and solvent-resistant aliphatic polyketone membrane for high-flux filtration of difficult oil-in-water micro- and nanoemulsions

Comprehensive fouling resistance, high permeability, high rejection, and robustness are indispensable criteria for advanced oil/water separation membranes intended for sustainable operation under harsh conditions. Accordingly, in the present study, a new class of zwitterionic-polyelectrolyte-grafted aliphatic polyketone (PK) membranes was prepared by the highly controllable surface-initiated atom transfer radical polymerization (SI-ATRP) of N-(3-sulfopropyl)-N-methacroyl-oxyethyl-N, N-dimethylammonium betaine (SBMA) on highly porous and hydroxylated PK membranes. The PK-g-PSBMA membrane prepared with 10-min grafting modification exhibited excellent solvent-resistant underoil superhydrophilicity as well as underwater superoleophobicity and ultralow protein adhesion. The low mass-transfer resistance, low fouling potential, and strong solvent resistance of the porous hydroxylated PK substrate along with the ultralow fouling nature of the zwitterionic SMBA layer, endowed the PK-g-PSBMA membranes with self-cleaning properties, sustainably high emulsion fluxes of 1200-1800 Lm(-2) h(-1) bar(-1), low oil permeations at 6-33 ppm, and high flux recovery ratios of 82-98%, even for difficult micro-and nanoemulsions containing small oil droplets and complicated pollutants (surfactant, high salinity, and natural organic matters). Thus, PK-g-PSBMA membranes with simple preparation route and comprehensive performances show great potential for treatment of challenging oily wastewater.