Bimetal Enhanced Covalent Organic Frameworks Catalytic Membranes for Concurrent Conversion and Separation

Traditional nanofiltration membranes face challenges such as membrane fouling and difficulties in achieving precise separation of small organic molecules. A promising solution to these issues is the preparation of thin-film nanocomposite membranes. In this study, Cu and Ag bimetals were incorporated into covalent organic frameworks to fabricate thin-film nanocomposite membranes. The hydrophilic monomer 1,3,5-tris(4-aminophenyl) benzene of covalent organic frameworks was introduced as a water phase monomer during interfacial polymerization to enhance the organic–inorganic compatibility. The incorporated covalent organic frameworks within the thin-film nanocomposite membrane loosened the selective layer, resulting in an enhanced permeability of 24.6 LMH bar⁻¹. The membrane exhibited a rejection rate over 99.0% for Congo Red, Xylene Brilliant Cyanine G, and Reactive Blue, while exhibiting relatively low rejection rates of MgCl₂ and NaCl. Moreover, the outstanding catalytic capability of the incorporated bimetals led to a 4-nitrophenol conversion rate of 84.38%, enabling simultaneous conversion and separation. The integration of covalent organic frameworks and bimetals also imparted robust antibacterial properties, significantly enhancing operational stability. In conclusion, the covalent organic framework-Cu/Ag-based thin-film nanocomposite membrane demonstrated superior catalytic and separation capabilities, presenting a promising alternative for advanced filtration applications.