Synergistic interaction of Z-scheme 2D/3D g-C3N4/BiOI heterojunction and porous PVDF membrane for greatly improving the photodegradation efficiency of tetracycline

Designing photocatalytic membranes with excellent photocatalytic and self-cleaning ability based on the synergistic effect between the crystal structure of membrane matrix and photocatalyst is highly desirable. Herein, Z-scheme 2D/3D g-C3N4/BiOI heterojunction blended in beta-phase polyvinylidene fluoride membrane (beta-phase PVDF) was prepared via solvent crystallization and phase inversion technique. As expected, the designed g-C3N4/BiOI/beta-phase PVDF photocatalytic membranes (CN/BI/beta-phase PVDF PMs) achieved exceptional photocatalytic degradation efficiency for tetracycline (94.6%) as compared to the CN/BI heterojunction power (84.0%) and two other control membrane matrixes (CN/BI/PAN and CN/BI/CA PMs) within 120 min. Meanwhile, the dynamic cyclic degradation system of CN/BI/beta-phase PVDF PMs was also investigated that reached to be 94.8% in 80 min. Besides, the CN/BI/beta-phase PVDF PMs not only had outstanding self-cleaning activity and remarkable permeability (up to 30,688 Lm(-2).h(-1)) but also had high stability and reusability even after five runs. Importantly, the hydroxyl radical detection and ESR analysis identified that the beta-phase PVDF membrane could promote photoinduced carrier separation efficiency of 2D/3D g-C3N4 /BiOI heterojunction. This work may open up a novel strategy for designing and constructing high-efficient photocatalytic membranes for water treatment. (C) 2020 Published by Elsevier Inc.

Automated summary

This study successfully designed photocatalytic membranes with exceptional photocatalytic degradation efficiency and self-cleaning ability by blending Z-scheme 2D/3D g-C3N4/BiOI heterojunction with beta-phase PVDF membrane matrix. The membranes showed remarkable permeability, stability, and reusability, as well as enhanced photoinduced carrier separation efficiency, opening up a novel strategy for high-efficient photocatalytic membranes in water treatment applications.