Biomimetic and durable sea grape-like COFs membrane for high performance emulsion separation and dye removal

This study leverages a traditional in-situ growth method to prepare covalent organic frameworks (COFs) membranes that can effectively treat oil/water mixtures, especially challenging oil-water emulsions. We construct bionic functional layers of COFs in situ on the fiber surface, that feature a mechanically robust, strong interfacial adhesion, unique hydrophilicity, reduce pore clogging and improve the specific surface area, which facilitates adsorption. Tightly weaving these fibers and COFs produces Eucommia ulmoides gum (EUG)@TAPB-PDA-COF membranes, the separation efficiency up to 99 % or more. Gravity-driven separation is employed to effectively treat n-hexane-in-water emulsion, attaining a flux of up to 2597 ± 14 L·m^-2·h^-1. The EUG@TAPB-PDA-COF demonstrate outstanding chemical stability, maintaining structural integrity when exposed to strong acids, bases, high-concentration saline solutions, and various organic solvents. The EUG@TAPB-PDA-COF show superior adsorption capacity for organic dyes, achieving removal efficiencies exceeding 93 % for crystalline violet. These excellent properties make EUG@TAPB-PDA-COF an ideal candidate for the treatment of oily water waste streams and the removal of dyes.