Oil-water Separation Research Articles

Superhydrophobic composite coatings for photocatalysis and oil–water separation: durable and eco-friendly solutions for industrial applications

Superhydrophobic composite coatings for photocatalysis and oil–water separation: durable and eco-friendly solutions for industrial applications

Mesoporous Silica Supported Hydrophilic Ionic Liquid Gel Microspheres for Solvent-Free Deep Oxidative Desulfurization.

Solvent-free oxidative desulfurization can avoid environmental pollution caused by organic solvents as well as prevent loss of fuel during the oil-water separation process. In this work, first, hydrophilic ionic liquid gel microspheres with [BMIM]BF4 and PHEMA as the dispersion medium and gel network, respectively, were successfully prepared by using mesoporous silica microspheres as a supporting skeleton capable of stabilizing the gel through an anchoring effect, and then the catalyst [BMIM]PW and oxidant H2O2 were incorporated into the gel microspheres to construct a liquid compartment microreactor for deep desulfurization. The prepared microreactor (SiO2@[BMIM]PW/ILG-microspheres) has excellent extraction-catalytic capacity and exhibited ∼100% desulfurization ratio for a model oil of n-heptane with 500 ppm of DBT at 60 °C for 3 h without solvents. Additionally, the prepared microreactor can absorb hydrophilic desulfurization products after the reaction and has advantages of reusability and simple recovery without polluting the fuel oil, which is beneficial for potential petroleum industrial application.

Use of the droplet convergence effect of under-medium superlyophilic membranes in designing a system for on-demand separations of oil-in-water and water-in-oil emulsions

Separation using superwetting membranes that have discrepant interactions with water and oil, primarily those that display extreme liquid repellence, is a facile approach for oily wastewater treatment and purification of water-containing oil. However, these kinds of membranes suffer from size-sieving limitation. Owing to greater affinity toward dispersed droplets over liquid media, under-medium superlyophilic membranes have greater flexibility in the design of superwetting interfaces for oil–water separation. Herein, two membranes with completely opposite superwettabilities both in air and under oil/water media were utilized to create an integrated system for effective, on-demand separation of oil-in-water and water-in-oil emulsions. At superwetting interfaces, the under-medium superlyophilic membrane facilitates convergence of emulsion droplets while the other membrane intercepts converged droplets. As a result, the integrated membranes exhibit high purification capabilities of water and oil in surfactant-stabilized emulsions (e.g., > 99.97 % oil purification under gravity). The viscosity-dependent fluxes are > 550 L m−2h−1 when the viscosities of the liquid media are ≤ 1 mPa s. In contrast, an integrated system in which conventional in-air superhydrophilic membranes are utilized in place of the under-medium superlyophilic membranes does not efficiently separate the emulsions. The unique affinity profiles will endow under-medium superlyophilic membranes with a high potential for liquid–liquid separation.

Multifunctional lignin-reinforced cellulose foam for the simultaneous removal of oils, dyes, and metal ions from water

Pollutants emitted by industry pose an emerging threat to ecosystems, human health and native species, which has attracted global attention. At present, most of the biomass-based water remediation materials suffer from the poor mechanical properties, complexity of the modification process, single function and low adsorption capacity. Therefore, a high-strength lignin/cellulose foam absorbent (LCMA) with super-hydrophilic surface was developed for wastewater treatment by using lignin as the skeleton to crosslink cellulose through sol-gel method. Combined with an abundance of reactive functional groups and a highly porous structure, LCMA demonstrated a superior absorption and removal performance for cationic dyes and heavy metal ions, with separation efficiencies exceeding 99.76 % for cationic dyes and 99.85 % for heavy metal ions. Further modification of LCMA by a facile method using polydopamine (PDA) and polyethyleneimine (PEI) imparted superhydrophilicity to the foams. The developed LCMA@PDA@PEI exhibited an impressive immiscible oil-water separation performance and emulsion separation performance (Separation efficiency >99.95 % for immiscible oil-water mixtures and >99.05 % for oil-in-water emulsions). With the capabilities of simultaneous removal for dyes, heavy metal ions and oil pollutants from water, LCMA holds a broad application prospect in the water remediation, especially in the treatment of polluted water with complex components.

Exploring the Possibilities of Using Recovered Collagen for Contaminants Removal—A Sustainable Approach for Wastewater Treatment

Collagen is a non-toxic polymer that is generated as a residual product by several industries (e.g., leather manufacturing, meat and fish processing). It has been reported to be resistant to bacteria and have excellent retention capacity. However, the recovered collagen does not meet the requirements to be used for pharmaceutical and medical purposes. Due to the scarcity of water resources now affecting all continents, water pollution is a major concern. Another major field that could integrate the collagen generated as a by-product is wastewater treatment. Applications of collagen-based materials in wastewater treatment have been discussed in detail, and comparisons with already frequently used materials have been made. Over the last years, collagen-based materials have been tested for removal of both organic (e.g., pharmaceutical substances, dyes) and inorganic compounds (e.g., heavy metals, noble metals, uranium). They have also been tested for the manufacture of oil-water separation materials; therefore, they could be used for the separation of emulsified oily wastewater. Because they have been analysed for a wide range of substances, collagen-based materials could be good candidates for removing contaminants from wastewater streams that have seasonal variations in composition and concentration. The use of recovered collagen in wastewater treatment makes the method eco-friendly and cost efficient. This paper also discusses some of the challenges related to wastewater treatment: material stability, reuse and disposal. The results showed that collagen-based materials are renewable and reusable without significant loss of initial properties. In the sorption processes, the incorporation of experiments with real wastewater has demonstrated that there is a significant competition among the substances present in the sample.

Fabrication of Micro/Nanostructured Copper Fibers by Vibration Cutting for Felt-Based Freshwater Purification

Freshwater purification from wasted water and seawater is crucial in addressing the global problem of water scarcity. Porous fiber felt with a micro/nanostructure emerges as an efficient approach for water purification; however, its production usually relies on chemical postprocessing to create micro/nano structures on the fiber surface, which might pollute the environment. This study proposed an ecofriendly method to produce micro/nanostructured copper fiber felt without chemical treatment. First, a new transverse-feeding vibration cutting is proposed to fabricate micro/nanostructured fibers with controllable structure characteristics. Through the sintering of the structured fibers without postprocessing, the fiber felt can be produced in an ecofriendly way and exhibit special wettability and excellent photothermal properties. Felt-based freshwater purification, including oil–water separation and solar-driven seawater desalination, can be realized effectively. Results show an oil–water separation efficiency of > 90% and a high evaporation rate of water of > 1.08 kg m−2 h−1 at 73 mW cm−2 are achieved, demonstrating the application prospect of the produced fiber felt.

Rice husk-derived self-healing superhydrophobic films using solvent-less approach for drag reduction and oil absorption behaviour

The present work focuses on a sustainable approach to transform rice-husk waste into self-healing superhydrophobic films with potential application for drag-reduction and oil absorption. Rice husk was transformed into amorphous nano silica particles (d50 ∼ 150 nm) exhibiting mesoporosity with a surface area of 400 m2/g. Superhydrophobic films fabricated using a solvent-less approach showed the transition from flattened to nano-globular morphology with increasing silica content in polydimethylsiloxane (PDMS), leading to exceptional superhydrophobicity. The optimized film with a particle fraction of 60 % exhibited high de-wetting (> 150º) and mechanical strength (∼7 MPa). The film showed extremely low water droplet adhesion of ∼19 μN, similar to lotus leaf owing to high negative Laplace pressure. Significantly, the film exhibited persisting de-wettability and endurance under harsh chemical, thermal, and mechanical conditions. The robustness is further fortified with room temperature self-healing and real-time self-regeneration characteristics, persisting even after exposure to strong acids and significant abrasion. The multidimensional aspects of the film embarked with a 70 % drag reduction and effective oil-water separation. The present work not only provides a sustainable pathway for managing agricultural waste but also a practical and easy-to-implement approach to tackle oil spill incidents.

Dopamine triggered the polymerization and co-deposition of HEMA on PVDF membranes to prepare oil-water separation membranes

A one-step co-deposition method based on dopamine and hydrophilic hydroxyethyl methacrylate (HEMA) was proposed for the modification of polyvinylidene fluoride (PVDF) membrane, which could ameliorate its oil-water separation performances and hydrophilicity. A range of modified membranes were prepared by adding different content of HEMA in the reaction solution. For the improved membrane, the minimum water contact angle can reach 13.63°, and the maximum underwater oil contact angle can reach about 150°. The pure water flux for the improved membrane reaches 9668 L·m-2·h-1·bar-1, showing excellent hydrophilicity. In addition, the separation efficiency of the improved membrane for a variety of oil-water emulsions exceeds 98%, indicating good permeability and circulating oil resistance. At the same time, this approach is also applicable to other membranes on account of the extensive availability of dopamine.

Preparation of novel nanoparticle demulsifier and its demulsification for surfactant-stabilized crude oil emulison

The application of nanoparticle (NP) demulsifiers in processing the emulsified crude oil production fluid is of great significance for improving production efficiency and reducing energy consumption in crude oil extraction. In this work, a novel NP demulsifier (PPA@KAO) was prepared by chemically modifying the mineral kaolinite (KAO) nanoparticles using γ-Methacryloyl propyltrimethoxysilane (MPS) and polyether-polyquaternium (PPA). The morphology and structure of the PPA@KAO demulsifiers were characterized by FT-IR, SEM, TG, XPS and Zeta potential. The contact angle measurements, interfacial tension (IFT) characterization, and the distribution of nanoparticles in the oil-water phase showed that PPA@KAO have good amphiphilicity and interfacial activity. The demulsification performance of PPA@KAO demulsifiers for a sodium dodecyl benzene sulfonate (SDBS) stabilized crude oil emulsion was studied with bottle method. It was found that the oil-water separation could be completed within 20 min, with a demulsification efficiency of 96.75 % at a dosage of 3 g L−1，pH of 6 and temperature of 30°C. Such a result indicates that the PPA@KAO NP demulsifier can achieve rapid and efficient demulsification for the surfactant-stabilized crude oil emulsion at room temperature. The demulsification mechanism of PPA@KAO for the SDBS-stabilized crude oil emulsion was well revealed, which provides an important synthetic strategy of how obtaining an effective NP demulsifiers by regulating the amphiphilicity and surface functional groups of the nanoparticles.

Preparation and properties of bio-based PA56/SiO2–NH2 composite nanofiber membranes for high efficiency oil-water separation

With the continuous development of environmental protection and resource recycling demands, the development of bio-based separation membrane materials has increasingly attracted attention. Bio-based polyamide 56 (PA56), exhibiting excellent hydrophilicity, spinnability, and mechanical properties, is expected to complement and replace traditional separation membrane materials. In this study, the electrospinning preparation and structural control of PA56 nanofiber membranes were achieved through the optimization of PA56 content and mixed solvent ratios. The study found that when the PA56 content was 16 wt% and the formic acid to acetone ratio in the mixed solvent was 8:2, the nanofiber diameter distribution was the most uniform. Building on this, amino-functionalized modified silica (SiO2–NH2) nanoparticles were introduced to prepare PA56/SiO2–NH2 composite nanofiber membranes featuring a cobweb-like nanofiber network and micro-nodule structure. The effects of the addition of SiO2–NH2 nanoparticles on the morphology, structure, and properties of the fiber membranes were studied. The results indicate that the control of the mixed solvent ratio and the addition of SiO2–NH2 nanoparticles led to the formation of a cobweb-like nanofiber network and micro-nano nodular structure on the nanofiber surface, enhancing the hydrophilicity of PA56 nanofiber membranes. The M − 3 membrane with a nanoparticle addition amount of 0.8 wt% exhibited high hydrophilicity and underwater superoleophobic properties, achieving efficient separation of stable oil-in-water emulsions with a separation efficiency of 99.8 %. This work provides a new bio-based membrane material and its preparation method for treating oily wastewater using the membrane separation method.

Preparation of the sandwiched PS-SiO2-PVAc-SiO2 electrospinning fiber membrane with super-hydrophobic and self-cleaning and its performance in oil-water emulsion separation

Oil-water emulsion separation could improve the efficiency of oil resources and reduce environmental pollution. The efficiency of oil-water separation was directly affected by the surface hydrophobicity of the membrane and its reliability and reusability. Therefore, the construction of a reliable and reusable super-hydrophobic surface was very important. In this research, the EFM with sandwich structure of PS-SiO2-PVAc-SiO2 was easily fabricated by a three times liquid phase induction process and heat treatment. The PS-SiO2-PVAc-SiO2 EFM was first formed by a triple liquid phase induction process, then the EFM was heat-treated, the PVAc, which is a heat-sensitive material, resulting in SiO2 nanoparticles being welded onto PS fibers. The rolling contact angle experiment at an inclination of 8° proved that the PS-SiO2-PVAc-SiO2 EFM has super-hydrophobic properties. Meanwhile, the PS-SiO2-PVAc-SiO2 EFM showed excellent stability and reliability of super-hydrophobic properties after the EFM was washed or taped. In addition, the PS-SiO2-PVAc-SiO2 EFM had self-cleaning function and fine oil-water separation property. The oil-water separation efficiency was over 99.50 % and the flow rate was 68 L/m2h. After 5 times of oil-water separation, the flux and separation efficiency did not decrease significantly, which proved that the PS-SiO2-PVAc-SiO2 EFM could be reusable.

Facile Preparation of Raspberry-Like SiO2@Polyurea Microspheres with Tunable Wettability and Their Application for Oil-Water Separation.

Raspberry-like microspheres have been widely used as superhydrophobic materials, photonic crystals, drug carriers, etc. Nevertheless, their preparation methods, usually consisting of multiple steps, are generally time- and energy-consuming. Herein raspberry-like SiO2@polyurea microspheres (SiO2@PUM) are readily prepared via a one-step precipitation polymerization of isophorone diisocyanate in a H2O/acetone mixture with the presence of SiO2 particles. The sphere size, surface roughness, and SiO2 content of SiO2@PUM are easily adjustable by varying the experimental conditions. TEM and SEM observations reveal that the final SiO2@PUM exhibits a core-shell structure, with polyurea (PU) in the core and SiO2 particles as the shell. In the process, the SiO2 particles were initially located on the PUM surface as a monolayer. With the reaction proceeding, the monolayer of SiO2 particles became thicker, forming a thicker layer of SiO2 particles on PUM due to the accumulation of SiO2 particles, leading to a multilayer structure of SiO2 particles on the shell of SiO2@PUM. The formation mechanism of the raspberry-like SiO2@PUM was thoroughly discussed and ascribed to electrostatic attraction between the positively charged PU and negatively charged SiO2 particles. Once dried, SiO2@PUM was superhydrophobic and turned hydrophilic if water-wetted. Using a layer of SiO2@PUM, effective separation with good reusability for a variety of oil-water mixtures was achieved regardless of the oil density and types of oil-water emulsions. This work presents a novel protocol for the preparation of raspberry-like microspheres with tunable wettability via a rapid and green process, and the resulting microspheres are highly effective for the separation of diverse types of oil-water mixtures.

Tannic Acid Film Based on One-Dimensional Supramolecular Self-Assembly for Electrical Conductivity and Oil-Water Separation.

Tannic acid is widely regarded as one of the most promising natural polyphenolic compounds. However, current research predominantly focuses on the utilization of its phenolic hydroxyl groups, with limited exploration of the functional potential of its aromatic structure. Herein, one-dimensional nanofibers based on supramolecular self-assembly were successfully prepared through the simple alkylation reaction of tannic acid and the π-π stacking of aromatic structures. These fibers, with lengths reaching tens of micrometers and an average height of 10 nm, were clearly observed using SEM and AFM. A film with excellent electrical conductivity (σ = 37.9 μS/cm) was fabricated by vacuum filtering the organic suspension of these fibers, which was 100-fold higher than that of the TA film. Additionally, the hydrophobic and lipophilic properties of Bn-TA were further investigated through oil-water separation experiments, where the Bn-TA membrane displayed excellent separation efficiency and durability, maintaining stable performance over multiple cycles. This strategy presents opportunities for the high-value utilization of tannic acid.

Water drop transportation on wettability switchable surface via anisotropic molecules

Active control of the transportation of liquid drops on a horizontal surface is achieved using surfaces with switchable wettability via remote stimuli. However, the mechanism how the dynamic wettability influences drop dynamics is rarely reported. In this paper, we demonstrate that a surface with switchable wettability induces depinning of the contact line through re-orientation of anisotropic molecules. We investigated the dynamics of contact lines and contact angles during the initiation of drop movement by the advancing and receding angles of the surface. We found that imbalance between advancing and receding angles with respect to the dynamic contact angle provides the force needed to overcome the energy barrier due to contact angle hysteresis on the surface. We discovered that the driving energy is accumulated with oscillations in contact angle until it breaks the pinning energy barrier. Understanding the role of dynamic contact angles in drop movement on switchable surfaces paves the way for designing effective fluid manipulation devices, such as water harvesters, biosensors, and oil–water separators.

Durably Superhydrophobic Magnetic Cobalt Ferrites for Highly Efficient Oil-Water Separation and Fast Microplastic Removal.

Microplastic pollution has become a primary global concern in the 21st century. Recyclable magnetic particles with micro-nanostructures are considered an efficient and economical way to remove microplastics from water. In this study, superhydrophobic magnetic cobalt ferrite particles were prepared by using a simple coprecipitation method combined with surface functionalization. The micromorphology, chemical composition, hysteresis loop, and surface contact angle of the functionalized cobalt ferrite were characterized. The separation efficiency and absorption capacity of cobalt ferrite particles in water-oil separation and microplastic removal were investigated. The results showed that the saturation magnetic field intensity of cobalt ferrite was 65.52 emu/g, the residual magnetization intensity (Mr) was 18.79 emu/g, and the low coercivity was 799.83 Oe. Cobalt ferrites had stable superhydrophobicity in the pH range of 1-13. The separation efficiency of cobalt ferrite powder for four oil-water mixture separations was higher than 94.2%. The separation efficiency was as high as 99.6% in the separation of the hexane and water mixtures. Due to the synergistic effect of the hydrophobic effect and van der Waals force, the functionalized magnetic cobalt ferrite had a high and stable microplastic removal efficiency and capture capacity. The removal efficiency of microplastics was close to 100%, and the capture capacity was 2.56 g/g. After ten microplastic removal cycles, the removal efficiency reached more than 98%, and the surface contact angle was still greater than 150°.

Constructing multi-path channels in graphene oxide-based membrane for high-efficiency oil/water separation

Graphene oxide (GO) membranes have demonstrated significant potential for effective wastewater treatment; however, their tortuous and irregular water transport pathways through stacked nanosheets pose considerable challenges. In this study, we present a novel approach for fabricating faveolate-structured graphene oxide nanomesh (GONM) membranes, enhanced by the in situ growth of Co(OH)2 nanosheets to facilitate oil–water separation. The incorporation of in-plane pathways through the porous GONM, alongside the enlargement of interlayer pathways from Co(OH)2 growth, significantly improves water permeance. The nanopores present in the holey GONM reduce diffusion pathways, while intercalation of Co(OH)2 nanosheets increases channel sizes and stabilizes the GONM structure. By manipulating the mass ratio between GONM and cobalt salt, we optimized the membrane, achieving an exceptional water permeance of 224.2 L m-2h−1 bar−1, surpassing GO membranes. Additionally, the resultant membranes exhibit remarkable underwater anti-oil adhesion performance and efficient separation capabilities for a wide variety of oil-in-water emulsions, with separation efficiencies exceeding 99.1 %. This work provides valuable insights into the intentional manipulation of surface topography and hierarchical nanochannels in membrane materials, paving the way for high-efficiency water treatment solutions.

Robust mussel-inspired LBL carbon nanotube-based superhydrophobic polyurethane sponge for efficient oil–water separation utilizing photothermal effect

Superhydrophobic materials possessing efficient and rapid oil–water separation capabilities, as well as robustness, have emerged as the epicenter of global attention. Conventional three-dimensional adsorbent materials often succumb to impaired performance under extreme environmental conditions, rendering it arduous to ensure the efficacy of oil–water separation, and confining the application scenarios. In this study, polyurethane sponges (PUs) co-modified with stearic acid (SA), polydimethylsiloxane (PDMS), and multi-walled carbon nanotubes (MWCNTs), designated as SA-PDMS/MWCNTs@PU (SPMPU), were successfully synthesized via layer-by-layer (LBL) self-assembly and liquid-phase deposition. The SPMPU sponge exhibits an overall separation efficiency of not less than 90 %. It boasts a stable adsorption capacity, formidable mechanical properties, and commendable reusability. SPMPU sponges maintain unparalleled stability in extreme environments, such as strong acids and alkalis, and in the photothermal effect experiment, the SPMPU sponge can attain a temperature of 101.5 °C within 2 min, with rapid reaction kinetics, high efficiency, and unwavering stability. Through the photothermal effect-assisted oil–water separation, a reliable solution is furnished for the current oil–water separation endeavors. The SPMPU sponge preparation is uncomplicated, economical, and yields stable performance, holding significant potential for application in marine oil spills and industrial oil–water separation scenarios.

A robust and high-throughput superhydrophobic-superoleophilic Zn/Ni composite coating prepared on stainless steel mesh for oil-water separation

Frequent oil spills and the discharge of oily wastewater have adverse effects on the environment and ecosystems. Against the backdrop of escalating environmental concerns, developing high-performing and eco-friendly oil-water separation techniques is crucial. In this study, we successfully created a PFOTS-Zn/Ni superhydrophobic-superoleophilic coating, abbreviated as PZNM, by electroplating Zn2+ and Ni2+ on the stainless steel mesh, followed by modification with perfluorooctyltriethoxysilane-ethanol solution. The wettability test results show that the water contact angle (WCA) reaches 161.3°, with a water sliding angle (WSA) of 2°, and the oil contact angle (OCA) is approximately 0°. Subsequently, the PZNM samples were subjected to tests including blade scratching combined with sandpaper abrasion, tape peeling, bending tests, submerging in acidic and alkaline solutions, high-temperature gradient exposure, and electrochemical corrosion to verify their outstanding long-term durability. Most importantly, it can be shaped into a practical continuous oil-water separation device. In the oil-water separation test, it was found that the superhydrophobic-superoleophilic PZNM achieves highly efficient oil-water separation, with a water/n-hexadecane separation efficiency of up to 93.2 % and a water-chloroform separation flux of 6450±30 L·m−2·h−1. The preparation process is straightforward and green, providing an economical solution. This design holds considerable prospects for applications in the domain of oil-water separation.

All-electrochemical-prepared, efficient and robust superhydrophilic/underwater superoleophobic meshes for synchronously achieving oil-water separation and water-soluble pollutant photodegradation

Superhydrophilic/underwater superoleophobic “water-removing” type membranes can overcome the issue of surface themselves easily fouled or even blocked by oils that seriously affects the oil-water separation capacity and limits the recycle use, and thus attract a great deal of research attention. In this work, we employed the electrochemical deposition method to fabricate Cu3(PO4)2 nanosheets (NSs) vertically grown on a copper mesh (COM) to achieve efficient oil-water separation, followed by the deposition of titanium dioxide (TiO2) nanoparticles and graphitic carbon nitride (g-C3N4) nanosheets on the surface of Cu3(PO4)2 nanosheets-wrapped mesh (Cu3(PO4)2@COM), respectively. The composited meshes of TiO2@Cu3(PO4)2@COM and g-C3N4@Cu3(PO4)2@COM not only showed the considerable superhydrophilic/underwater superoleophobic property in the application of oil-water separation, but also simultaneously exhibited the desirable photocatalytic activity for the degradation of water-soluble pollutants as the water passed through the meshes. The oil-water separation efficiency of TiO2@Cu3(PO4)2@COM and g-C3N4@Cu3(PO4)2@COM can reach as high as 97 % and 96 % that both of meshes have the water flux of various water-oil mixtures above 3250 L/m2h, along with their degradation efficiency of 79 % and 90 % for RhB pollutant under full spectrum light irradiation, respectively. In addition, the as-prepared meshes have the robust, sustainable and stable properties through ten-cycles test of oil-water separation and photocatalytic degradation without significant performance decay. Our primary results provide a potential and simple route to construct multifunctional membrane materials for synchronously achieving water purification in oily wastewater.

Enhancing durability and oil-water separation efficiency with plasma-treated graphene oxide coated mesh

In recent years, there has been a surge in interest surrounding the fabrication and utilization of superhydrophobic and superhydrophilic surfaces, driven by their exceptional functionalities and properties. Graphene Oxide (GO) has inherent hydrophilicity and underwater superoleophobicity, which has made this material a particularly capable candidate for oil-water separation. Addressing the persistent challenge of efficient oil-water separation in industrial contexts, this study presents the fabrication of a GO-coated stainless steel mesh via a facile dip coating method augmented by an intermediate two-step O2 plasma treatment. The coated meshes were tested with various oil and water mixtures, including neutral, acidic, saline, and hot water, to find separation efficiency and recyclability. Notably, the meshes can achieve excellent separation efficiency of approximately 98.9 % and a superior flux of 11,464 L m−2 h−1 driven by gravity. This is a significant improvement over GO-coated meshes without O2 plasma treatment. Moreover, the plasma-treated meshes exhibit robust long-term durability and chemical stability, maintaining high underwater oil contact angles ≥119° even after extended immersion in diverse pH mediums and salt solutions for 150 days. This work showcases the practical viability of plasma-treated GO-coated meshes for oil-water separation applications and establishes a framework for systematically evaluating their long-term performance in harsh immersion conditions.