An Engineered Membrane Separation System Using Binder-Free Immobilized Heterojunction Photocatalyst for Enhanced Energy-Efficient Organic Dye Separation

Abstract

MOF-based photocatalytic membranes provide a promising solution for efficient, selective, and continuous pollutant removal by effectively integrating membrane separation and photocatalytic degradation. However, a combination of factors, including single-MOF photocatalysis, high driving pressure, and binder-based immobilization, limit the photocatalytic efficiency for large-scale organic dye separation. Herein, a binder-free immobilization strategy combined insitu MOF-on-substrate growth and pressure-driven coating methods is proposed to construct multi-component collaborative heterojunction photocatalysts on copper foam, with high photocatalytic activity on the surface. This stable, yet highly exposed, multi-component heterojunction photocatalyst on the copper foam surface demonstrates rapid and efficient degradation of various organic dyes. By leveraging a multi-component collaborative construction method and a kinetic model, we reveal a synergistic effect that enhances the photocatalytic reaction process, enabling efficient and rapid in-situ degradation of various water-soluble dye pollutants. Based on this synergistic effect, an engineered microfiltration membrane-like system, featuring a large specific surface area for abundant active sites, long transport channels, and excellent synergistic photocatalytic degradation properties, is also provided for the pressureless, continuous, and long-term separation of large-scale organic dyes from wastewater with high efficiency, showing great potential for practical large-scale organic pollutant treatment.