Hierarchical Micro/Nano‐Architected Nylon Mesh Integrated With Metal–Organic Framework, Cellulose Nanocrystal, and Graphene Oxide for High‐Efficient Oil–Water Separation

ABSTRACT The exploitation, transportation, and utilization of various oil products frequently generate substantial volumes of oily wastewater, making the development of efficient treatment methods imperative for addressing environmental pollution and water scarcity. In this study, sodium hypochlorite was first employed to oxidize and etch the surface of the nylon mesh separation membrane (NFM), resulting in a modified NFM (M‐NFM) characterized by a unique honeycomb‐like porous structure and an abundance of oxygen‐containing functional groups. Subsequently, a hydrophilic and positively charged UiO‐66‐NH 2 particle layer is in situ synthesized on the NFM surface, capitalizing on the abundant nucleation sites offered by carboxyl groups within the honeycomb framework, yielding the composite membrane of M‐NFM/UiO‐66‐NH 2 (M‐NFMU). To further enhance the oil–water separation performance of this composite membrane, surface‐functionalized cellulose nanocrystals (SF‐CNC) and graphene oxide (GO) were sequentially adsorbed onto the surface of the M‐NFMU membrane through a synergetic self‐assembly strategy. This process led to the formation of a hierarchical micro‐nano structure on the surface of the NFM, ultimately producing a composite membrane designated as M‐NFM@UiO‐66‐NH 2 /SF‐CNC/GO (M‐NFMUCG). During the oil–water separation process, water molecules engage in hydrogen‐bonding interactions with the amine, carboxyl, and hydroxyl functional groups present in the UiO‐66‐NH 2 , SF‐CNC, and GO structures. This interaction effectively captures and stabilizes a water film on the surface of the M‐NFMUCG membrane, preventing oil from coming into contact with it. As a result, the M‐NFMUCG exhibits remarkable superhydrophilicity, exceptional oil resistance, and outstanding oil–water separation performance, achieving a permeate flux of up to 16,361 L m 2  h −1 and an oil rejection rate exceeding 99.9% under gravity. Moreover, the M‐NFMUCG membranes exhibit excellent chemical stability and remarkable salt resistance, underscoring their significant potential for the treatment of oily wastewater.