Polytetrafluoroethylene hollow fiber membranes with thru hydrophilic channels for enhancing water transfer and anti-oil-fouling properties

Herein, a feasible method for hydrophilic modification of polytetrafluoroethylene (PTFE) hollow fibers via interfacial polymerization (IP) was proposed. 1, 3-Diamino-2-propanol (DAP) and trimesoyl chloride (TMC) were selected as monomers and a three-time IP method was adopted to construct hydrophilic channels within the membrane pores, thus effectively improving the hydrophilicity and permeability of membranes. The solvent of aqueous phase in conventional IP process was replaced by ethanol for better introducing amine monomers into membrane pores. The characterization results of Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and water contact angle (WCA) tests indicated the successful formation of polyamide (PA) layer within the membrane pores. In comparison to the ethanol pre-wetted control membrane, the PTFE hollow fibers modified under optimal IP conditions exhibited higher water flux (from 136.8 to 1059.1 kg m−2 h−1) and showed better resistance to both BSA (FRR from 53.4% to 92.3%) and soybean oil (FRR 16.4% from to 78.1%) after four cycles of filtration and cleaning. Simultaneously, the modified membranes demonstrated a favorable oil removal capacity (≥ 92%), and still maintained good stability after 24 h ultrasonic treatment and 8 d immersion tests in acid, alkali and oxidation solutions. This membrane holds significant application value in the treatment of oily wastewater.