Fabrication of self-assembled 0D-2D Bi2MoO6-g-C3N4 photocatalytic composite membrane based on PDA intermediate coating with visible light self-cleaning performance

A Self-cleaning surface can efficaciously solve the problem of irreversible contamination buildup on filtration membranes. Photocatalytic membranes were fabricated via vacuum assisted layer-by-layer (LBL) self-assembly of 0D-2D Bi2MoO6-g-C3N4 on a PDA coated thin-film composite PVDF substrate by Schiff base reaction. The rejection rate of the simulated polysaccharide was more than 90%, and that of the simulated protein was more than 80%. The combination of the membrane and the photocatalyst promoted the degradation of tetracycline hydrochloride by the composite membrane to 67.85% when original membranes had minor effect. Under visible light, reversible radiation pollutants (R-r) gradually replaced irreversible pollutants (R-ir) as the main pollutants. The flux recovery ratio (FRR) of 0D-2D Bi2MoO6-g-C3N4/PVDF membrane was 85% after being irradiated with visible light for 30 min. The flux recovery rate of contaminated photocatalytic membrane remained 75%, and the rejection was maintained in a stable range after four cycles of the cleaning operation under visible light. The results indicated that the excellent photocatalytic performance of 0D-2D Bi2MoO6-g-C3N4 photocatalysis material and the increase of multi-dimensional functional layer morphology on pollutant contact area improved the mechanical stability, interception performance and self-cleaning performance of the composite membrane. This work not only builds a new type of composite coating membranes, but also help us to further understand the relationship between the dimensions of photocatalytic materials and the improvement of photocatalytic membrane performance. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

A self-cleaning surface was created via vacuum-assisted layer-by-layer self-assembly of a photocatalytic membrane, effectively solving irreversible contamination buildup on filtration membranes. The rejection rates for simulated polysaccharides and proteins were high, indicating efficient filtration. This innovative composite membrane showed excellent photocatalytic performance and mechanical stability, highlighting the potential for improving photocatalytic membrane technology.