Inorganic–Organic Composite Hydrogels Inspired by the Mother of Pearl Used for Efficient Oil–Water Separation and Catalytic Degradation of Organic Pollutants

Abstract Traditional separation membranes suffer from inherent limitations of single functionality, severe fouling susceptibility, and incapability of simultaneous removal of dissolved organic pollutants in oily wastewater, which severely limit their advanced treatment and applications. To address the limitations of traditional separation membranes in terms of antifouling and multifunctionality, this study, inspired by the hierarchical structure of nacre, aims to develop a dual-functional inorganic–organic composite hydrogel membrane that possesses both efficient oil–water separation and simultaneous catalytic degradation capacity for organic pollutants. By successively constructing an Fe–Mo/tannic acid inorganic hydrogel layer and a β-cyclodextrin/polyacrylamide organic hydrogel layer on a microporous stainless steel mesh, a functionalized inorganic–organic composite hydrogel membrane (FMH@SS/PAC) was successfully fabricated. The membrane exhibits superhydrophilicity and underwater superoleophobicity and achieves a separation efficiency of over 99.5% for various oil–water mixtures solely under gravity with a pure water flux of 1.07 × 105 L·m–2·h–1. It also exhibits excellent cycling stability and antifouling ability (flux recovery rate of 87.32%). Additionally, it can activate peroxymonosulfate (PMS) and effectively degrade Rhodamine B (RhB) within 65 min. This study successfully prepares a highly performing “separation–degradation” dual-functional membrane. Its unique inorganic–organic composite strategy provides a new material solution and theoretical basis for the efficient advanced treatment and reuse of complex oily wastewater.