An interfacial networked self-cleaning membrane based on 2D/2D C-g-C3N4/BiVO4 heterojunction for photocatalytic degradation of tetracycline

Background Photocatalytic membrane technology has attracted widespread concern in the field of water purification due to its high-efficiency and eco-friendly. However, the active sites of photocatalyst are easily embedding in the polymer membrane, consequently reducing degradation efficiency of photocatalytic membrane. Methods In this study, two-dimensional/two-dimensional regenerated silk fibroin-carbonized carbon modified graphite carbon nitride/bismuth vanadate heterojunction (2D/2D C-g-C 3 N 4 /BiVO 4 ) with excellent photocatalytic performance was synthesized by electrostatic self-assembly method. Then C-g-C 3 N 4 /BiVO 4 heterojunction was selected as catalytic structural units, three-dimensional (3D) interfacial networked poly(vinylidene fluoride) membrane-supported C-g-C 3 N 4 /BiVO 4 heterojunction (C-g-C 3 N 4 /BiVO 4 /PVDF) was fabricated by electrospinning technique. The combination of C-g-C 3 N 4 /BiVO 4 heterojunction and interfacial networked PVDF membrane synergistically enhanced their permeability, antifouling and antibacterial performance. Significant findings The optimized C-g-C 3 N 4 /BiVO 4 /PVDF photocatalytic membrane had higher degradation TC efficiency (83.33 %) than other membrane samples, and the efficiency of bacterial inactivation of C-g-C 3 N 4 /BiVO 4 /PVDF could reach 99.00 %. The C-g-C 3 N 4 /BiVO 4 /PVDF exhibited tremendous enhancement in the permeability (13,488.2 L m −2 h −1 ) and flux recovery efficiency (94.44 %). The free radical trapping tests and ESR spectra indicated that superoxide radical (·O 2 ⁻ ) was the dominant active species. In addition, the as-prepared C-g-C 3 N 4 /BiVO 4 /PVDF could easily recover and reuse, and photocatalytic activity basically remain unchanged, highlighting the potential application of membrane photocatalyst for the practical wastewater treatment.