2D/2D Covalent triazine-based heterostructure membrane for highly enhanced photoactivity and anti-fouling ability

2D/2D S-scheme heterojunction membrane of covalent triazine frameworks@TiO2 (CTFs@TiO2) was fabricated through electrospinning, hydrothermal reaction, and vapor-assisted in situ polymerization. This hierarchical structure was composed of TiO2 nanosheets uniformly grown on electrospinning fiber, and the loading of tiny CTFs flakes. The CTFs@TiO2 heterojunction membrane achieved complete removal of antibiotic and dyes within 100 min of visible light irradiation. This highly enhanced photoactivity and hierarchical morphology also exhibited strong anti-fouling ability that backwash and photo-induced self-cleaning were responsible for membrane regeneration. In dynamic photocatalysis-separation system, the constructed membrane was capable of simultaneous purification of multiple pollutants of organics and oils, indicating the satisfactory adaptability and practical value. Based on XPS, DRS and selective deposition of Pt, a possible mechanism on the formation of S-scheme heterojunction, and an optimal state of "efficient match" between CTFs and TiO2 nanosheets were proposed.