Solventless Polymer-Grafted Mesh for Rapid and Efficient Oil–Water Separation

Abstract

We report a solventless bilayer strategy for grafting hydrophilic poly(methacrylic acid) (PMAA) onto metal meshes. The bilayer nanocoating consisted of ultrathin PMAA brushes grafted onto a highly crosslinked primer that binds to each mesh wire. The enrichment of hydrophilic functionalities on the PMAA-grafted mesh surface improved the surface hydration and underwater oil repellency over the PMAA-crosslinked mesh, which contributed to the formation and stabilization of continuous water films between mesh wires to reject oil penetration in repeated uses. The vapor-based nanocoating process maximized the retention of pore openings for high-flux oil–water separation. The retained permeability, together with the enhanced oil repellency, enabled the PMAA-grafted mesh to achieve excellent gravity-driven oil–water separation, with an oil rejection rate higher than 99%, water flux exceeding 50,000 L m–2 h–1, and flux decay less than 3% after 20 cycles of reuse. More importantly, the PMAA-grafted mesh preserved high separation efficiency and flux stability under conditions of high salinity and extreme pH.

A hydrophobic/oleophilic silica‐cellulose composite aerogel for oil–water separation

“…Frequent oil spills and oily domestic and industrial sewage discharge have caused catastrophic pollution to the marine environment and aquatic ecosystems. Various methods have been established to remedy water pollution by oil contamination, including combustion, 1 bioremediation, 2 mechanical oil recovery, 3 chemical treatment, 4 membrane filtration, 5–7 etc. However, these methods usually have their own drawbacks.…”

Peroxidase-Catalyzed Fabrication of a Mechanically Robust Nanofibrillated Cellulose-Based Aerogel with Antibacterial Activity for Efficient Oil–Water Separation

“…Various techniques have been utilized for oil–water separation, such as gravity separation, centrifugal separation, incineration, chemical flocculation, bioremediation, and oil adsorption. − Among them, physical oil adsorption method is commonly considered as a relatively economical and effective way to treat oily wastewater . Many hydrophobic and lipophilic materials such as carbon-based materials, polytetrafluoroethylene-coated meshes, polymeric porous materials, and polydimethylsiloxane-coated nanowire films, have been developed for the adsorption of residue oil from oily wastewater. − However, due to their inherent lipophilic nature, it is difficult to effectively separate the adsorbed oil from the interior of the above-mentioned materials, which easily leads to scaling on the material surfaces or blocking the internal porous structures, affecting the reuse effect of the oil-adsorbing materials . Therefore, it is critical to develop new materials with an efficient oil–water separation property and reusability.…”

“…Many hydrophilic/oleophobic materials have been constructed by integrating nano/microscale surface structures with appropriate chemical surface modifications. However, when their intricate topologies were disrupted, these materials may lose their hydrophilic and oleophobic properties. ,− Inspired by fish scales, the separation materials with super hydrophilic/underwater lipophobicity can substantially mitigate oil pollution, thereby enhancing the stability of oil–water separation. , Nanofibrillated cellulose (NFC) exhibits excellent superhydrophilicity and underwater lipophobicity, which are determined by the surface chemistry of NFC rather than the surface morphology such as roughness, and can maintain excellent stability even in harsh environments. , Therefore, applying NFC as a porous material can improve the fragility and low durability of the hydrophilic/oleophobic surface structure of the traditional materials. NFC aerogels exhibit significant advantages in oil–water separation due to their low-density, high-specific surface area, highly porous nanostructures, tunable wettability, and biodegradability. , However, the poor mechanical properties of NFC aerogels limit their further practical applications. , …”

“…8−11 However, due to their inherent lipophilic nature, it is difficult to effectively separate the adsorbed oil from the interior of the above-mentioned materials, which easily leads to scaling on the material surfaces or blocking the internal porous structures, affecting the reuse effect of the oil-adsorbing materials. 1 Therefore, it is critical to develop new materials with an efficient oil−water separation property and reusability.…”

“…NFC aerogels exhibit significant advantages in oil−water separation due to their low-density, high-specific surface area, highly porous nanostructures, tunable wettability, and biodegradability. 1,12 However, the poor mechanical properties of NFC aerogels limit their further practical applications. 20,21 Chemical and physical methods have been widely applied to establish covalent and noncovalent cross-linking networks between the molecular chains to improve the mechanical properties of composites including aerogels.…”