Construction of Asymmetric Filler Density Mixed-Matrix MOF Membranes via Liquid-Phase Ion Activation for Advanced Oxidation Processes

Mixed-matrix membrane (MMM) reactors incorporating metal-organic framework (MOF) fillers have significant applications in fields such as separation, catalysis, and chiral resolution. However, the traditional method of directly mixing MOF fillers with polymers results in a symmetric structure where most of the MOF fillers are uniformly distributed across the membrane reactor's cross-section. During usage, this leads to a pronounced trade-off between flux and efficiency and the waste of the MOF, as the rich pore characteristics and active sites of MOFs are not fully utilized. In this study, we propose a liquid-phase ion activation strategy that enables the in situ formation of a uniform and densely packed MOF shell layer on the membrane surface during the phase inversion process of MMM fabrication. This asymmetric density distribution of the MOF-based MMM reactor selectively induces the generation of considerable nonradical ¹O₂ in the peroxomonosulfate (PMS) system, demonstrating superior catalytic degradation performance against antibiotics like TC and dye molecules (with a flux of 1880 L m^-2 h^-1 and a <i>K</i>_app value of 648 min^-1), as well as outstanding cycling stability and environmental tolerance. This discovery sheds light on the design and engineering of composite membrane materials and applications for advanced oxidation processes in water purification.