Biomimetic Superhydrophobic Construction of a PTFE-HFM Surface with CNTs for Waste Oil Purification

The complex composition of industrial waste oil poses a severe challenge to efficient separation and recycling, urgently necessitating the development of membrane materials that combine high separation efficiency, excellent high-temperature stability, and antifouling performance. In this paper, a carbon nanotube (CNT)/polydimethylsiloxane polytetrafluoroethylene hollow fiber membrane (PPHFM) was fabricated via the wet impregnation method. Results indicated that CNTs were uniformly dispersed within the PDMS matrix, synergistically constructing a hierarchically rough surface and endowing the membrane with superhydrophobic and superoleophilic properties. The optimized membrane pore structure conferred molecular sieving ability, achieving a separation efficiency of 94.32% for water-in-oil emulsified oil. Simultaneously, the membrane exhibited excellent permeation flux: the initial flux for kerosene reached 454.96 L–1 m–2 h–1 bar–1, and the flux for waste oil at 150 °C was 47.39 L–1 m–2 h–1 bar–1. The poly(p-phenylene terephthalamide) reinforcement layer endowed the membrane with ultrahigh mechanical strength (tensile strength >450 MPa). The optimized CM-2 membrane (CNTs 2 wt %) exhibited outstanding antifouling properties and cycling stability: after 4 consecutive operational cycles, the flux recovery ratio remained at 81.8% in the high-temperature waste oil system; it maintained a high flux even after long-term operation with high-temperature waste oil. This study successfully fabricated a CNT/PPHFM material. This membrane can efficiently treat industrial waste oil and exhibits enhanced durability, demonstrating broad application potential in demanding environments.