Covalent Organic Framework Membrane with Turing Structures for Deacidification of Highly Acidic Solutions

Abstract The deacidification of highly acidic industrial wastewater, such as the spent fuel reprocessing feed liquid, is of great significance for the smooth progress of the subsequent treatment processes. Herein, a novel covalent organic framework (COF) membrane with bidirectional anisotropic Turing structures is synthesized for the first time and used for deacidification. The COF membrane presents linear and hydrophobic properties on one side and porous and superhydrophilic properties on the other side, which makes the water permeability of hydrophilic side 45 times higher than that of the hydrophobic side and effectively prevents the reverse osmosis of water. Impressively, the COF membrane has excellent thermal, acid, and irradiation stabilities, and an extraordinarily high ability to intercept metal ions in a complex multi‐ion solution containing 5 m HNO₃, with the interception rate up to 100%. However, H⁺ can easily pass through the membrane with the permeation flux of 1015.7 mol L⁻¹ m⁻², which realizes the efficient deacidification of high acidic solutions. This study provides not only a new idea for the design and preparation of Turing‐structural membranes, but also a feasible strategy for the deacidification and process simplification of spent fuel reprocessing feed liquid and other industrial wastewater with high acidity.