Oil-water Separation Research Articles

Facile Fabrication of Multifunctional Superhydrophobic Surfaces Synthesized by the Additive Manufacturing Technique Modified with ZnO Nanoparticles.

This article reports facile fabrication of a multifunctional smart surface having superhydrophobic self-cleaning property, superoleophilicity, and antimicrobial property. These smart surfaces have been synthesized using the stereolithography (SLA) method of the additive manufacturing technique. SLA is a fast additive manufacturing technique used to create complex parts with intricate geometries. A wide variety of materials and high-resolution techniques can be utilized to create functional parts such as superhydrophobic surfaces. Various materials have been studied to improve the functionality of 3D printing. However, the fabrication of such materials is not easy, as it is quite expensive. In this work, we used a commercially available SLA printer and its photopolymer resin to create various micropatterned surfaces. Additionally, we applied a low surface energy coating with ZnO nanoparticles and tetraethyl orthosilicate to create hierarchical roughness. The wettability studies of created superhydrophobic surfaces were evaluated by means of static contact angle using the sessile drop method and rolling angle measurements. The effects of various factors, including different concentrations of coating mixture, drying temperatures, patterns (pyramids, pillars, and eggbeater structures), and pillar spacing, were studied in relation to contact angles. Subsequently, all the functional properties (i.e., self-cleaning, oleophilicity, and antibacterial properties) of the as-obtained surfaces were demonstrated using data, images, and supporting videos. This inexpensive and scalable process can be easily replicated with an SLA 3D printer and photopolymer resin for many applications such as self-cleaning, oil-water separation, channel-less microfluidics, antibacterial coating, etc.

Fabrication of Polytetrafluoroethylene Composite Membrane via Laser Perforating and Nanosilica Coating for Efficient Oil–Water Separation

Fabrication of Polytetrafluoroethylene Composite Membrane via Laser Perforating and Nanosilica Coating for Efficient Oil–Water Separation

An easily-prepared superhydrophobic paper promoted by dodecanethiol and its oil–water separation mechanism

An easily-prepared superhydrophobic paper promoted by dodecanethiol and its oil–water separation mechanism

Numerical simulations on the separation performance of two-stage mini hydrocyclones connected in series

ABSTRACT Conventional hydrocyclones (CHCs) exhibit limited effectiveness in separating fine oil droplets from produced fluids, constraining overall oil-water separation efficiency. Mini hydrocyclones (MHCs) with smaller main diameter can further enhance the separation efficiency of fine oil droplets. This study constructs a two-stage series separation system using two individual MHCs. Simulations were conducted to investigate the effects of split ratio, water content, and oil droplet size on the separation performance. The adaptability of the series system to these parameters was thereby obtained. Results indicate the optimal separation efficiency is achieved when the total split ratio of the series system is 48%. The two-stage series system has better adaptability to the water content, and the separation efficiency keeps more than 97% when the water content is 86–98%, while the separation efficiency is lower than 92% when the water content is 86% in a single-stage MHC. When the inlet oil concentration exceeds 10%, for oil droplet sizes less than 0.15 mm, the two-stage series system outperforms single-stage MHCs operating independently.

Foldable, Stretchable, Superelastic, and Tunable Wettability Aramid Nanofiber Aerogels for Efficient Thermal Insulation and Oil-Water Separation.

Aerogels hold great potential in thermal insulation, catalytic supports, adsorption, and separation, due to their low density, high porosity, and low thermal conductivity. However, their inherent mechanical fragility and limited control functionality pose substantial challenges that hinder their practical use. In this study, a strategy is developed for the fabrication of cross-linked aramid nanofiber aerogels (cANFAs) by combining internanofiber surface cross-linking with ice-templating techniques. This approach enables the production of cANFAs with an ultralow density of 6.3 mg/cm3 while exhibiting robust mechanical properties, including exceptional mechanical resilience, withstanding 90% compression in air and 80% compression underwater for 100 cycles, and high stretchability with a tensile strain of 34%. The cANFAs demonstrate remarkable thermal insulation properties, with low thermal conductivities of 0.03816 W/(m·K) at room temperature and 0.03518 W/(m·K) at -40 °C. Additionally, the cANFAs exhibit tunable wettability, being hydrophilic and oleophilic in air while becoming superhydrophobic underwater, which enables efficient gravity-driven oil-water separation performance. This study presents a promising route to create robust and functional aramid nanofiber aerogels for practical applications across various fields.

Ultra-high flux electrospun PAN/MWCNTs/SiO2 membranes for oil–water separation: development and characterization

Ultra-high flux electrospun PAN/MWCNTs/SiO2 membranes for oil–water separation: development and characterization

Environmental and Wastewater Treatment Applications of Stimulus-Responsive Hydrogels.

Stimulus-responsive hydrogels have emerged as versatile materials for environmental and wastewater treatment applications due to their ability to adapt to changing environmental conditions. This review highlights recent advances in the design, synthesis, and functionalization of such hydrogels, focusing on their environmental applications. Various synthesis techniques, including radical polymerization, grafting, and copolymerization, enable the development of hydrogels with tailored properties such as enhanced adsorption capacity, selectivity, and reusability. The incorporation of nanoparticles and bio-based polymers further improves their structural integrity and pollutant removal efficiency. Key mechanisms such as adsorption, ion exchange, and photodegradation are discussed, emphasizing their roles in removing heavy metals, dyes, and organic pollutants from wastewater. Additionally, this review presents the potential of hydrogels for oil-water separation, pathogen control, and future sustainability through integration into circular economy frameworks. The adaptability, cost-effectiveness, and eco-friendliness of these hydrogels make them promising candidates for large-scale environmental remediation.

Imidazolium-Based Ionic Liquid Exhibiting Dual Hydrophilic and Oleophobic Properties without Polar End Groups.

Simultaneously hydrophilic and oleophobic surfaces offer substantial advantages for applications such as antifogging, self-cleaning, and oil-water separation. It remains challenging to engineer such surfaces without requiring polar functional groups. This study introduces HFIL, a novel ionic liquid (IL) coating that achieves simultaneous hydrophilic and oleophobic properties via a one-step dip-coating process without relying on polar functional groups. Key findings show that, despite the bulk form of HFIL having a high hexadecane contact angle (HCA) of 74.1° and an even higher water contact angle (WCA) of 87.6°, the IL forms a stable monolayer on high-energy surfaces exhibiting a much lower WCA of approximately 40° with minimal change to the HCA. Washing tests demonstrate that, even without the polar functional groups, there is a non-zero bonded thickness upon which the oleophobicity is comparable to polytetrafluorethylene (PTFE). These properties highlight HFIL's potential for durable applications in antifouling, antifogging, and environmental separation technologies, where selective liquid interactions are essential. This work contributes to a broader understanding of IL-based surface modifications, advancing the development of high-performance coatings.

Direct Ink Writing 3D Printing Polytetrafluoroethylene/Polydimethylsiloxane Membrane with Anisotropic Surface Wettability and Its Application in Oil-Water Separation.

Biological surfaces with physical discontinuity or chemical heterogeneity possess special wettability in the form of anisotropic wetting behavior. However, there are several challenges in designing and manufacturing samples with anisotropic wettability. This study investigates the fabrication of PTFE/PDMS grid membranes using Direct Ink Writing (DIW) 3D printing for oil-water separation applications. The ink's rheological properties were optimized, revealing that a 60% PTFE/PDMS composite exhibited the ideal shear-thinning behavior for 3D printing. Our research investigated the interplay between various printing parameters like the extrusion air pressure, layer thickness, feed rate, and printing speed, which were found to influence the filament dimensions, pore sizes, and hydrophobic properties of the grid membrane. Two distinct grid structures were analyzed for their wettability and anisotropic hydrophobic characteristics. The grid membranes achieved up to 100% oil-water separation efficiency in specific configurations. Separation efficiency was shown to be dependent on factors like intrusion pressure, grid architecture, and the number of layers. This study underscores the potential of DIW 3D printing in creating specialized surfaces with controlled wettability, particularly superhydrophobicity and anisotropy, paving the way for advanced environmental applications such as efficient oil-water separation.

Tunning the Wettability of the PVDF Membrane using the PVA-Stabilized TA-UiO-66-NH2 MOF Membranes to Separate Layered Oil-Water Mixture and Surfactant-Stabilized Emulsion.

This study introduces a UiO-66-NH2/Tannic acid/Polyvinylidene fluoride (UTP) composite membrane for efficient oil-water separation. Pristine polyvinylidene fluoride (PVDF) membranes, due to their hydrophobic nature, tend to foul during oil-in-water emulsion separation. By incorporating the metal-organic framework (MOF) UiO-66-NH2 and stabilizing it with tannic acid (TA) and polyvinyl alcohol (PVA), the membrane's hydrophilicity and antifouling properties were significantly enhanced. The water contact angle of the UTP membrane decreased from 121° to 3°, indicating a dramatic increase in hydrophilicity, while the underwater oil contact angle (UWOCA) of 119° demonstrated excellent oleophobicity. The modified membrane achieved over 99 % separation efficiency and improved flux by 15 times compared to the pristine PVDF. TA acted as a binder, ensuring uniform MOF dispersion and improving the composite's stability. The PVA further reinforced the structure, enhancing durability under operational conditions. Durability tests showed no significant MOF detachment after repeated use, confirming the stability of the UTP composite. The results highlight the potential of the UTP membrane for oil-water separation with superior permeability and fouling resistance.

Advancements in Superhydrophobic Paper-Based Materials: A Comprehensive Review of Modification Methods and Applications.

Superhydrophobic paper-based functional materials have emerged as a sustainable solution with a wide range of applications due to their unique water-repelling properties. Inspired by natural examples like the lotus leaf, these materials combine low surface energy with micro/nanostructures to create air pockets that maintain a high contact angle. This review provides an in-depth analysis of recent advancements in the development of superhydrophobic paper-based materials, focusing on methodologies for modification, underlying mechanisms, and performance in various applications. The paper-based materials, leveraging their porous structure and flexibility, are modified to achieve superhydrophobicity, which broadens their application in oil-water separation, anti-corrosion, and self-cleaning. The review describes the use of these superhydrophobic paper-based materials in diagnostics, environmental management, energy generation, food testing, and smart packaging. It also discusses various superhydrophobic modification techniques, including surface chemical modification, coating technology, physical composite technology, laser etching, and other innovative methods. The applications and development prospects of these materials are explored, emphasizing their potential in self-cleaning materials, oil-water separation, droplet manipulation, and paper-based sensors for wearable electronics and environmental monitoring.

2D Titanium Carbide MXene-Interfaced Zinc Oxide/Tungstite Architectures Adorned Mixed Matrix Polymer Membranes for Oily Wastewater Treatment.

An exceedingly porous and interwoven fibrous structure was achieved in this study by interlocking titanium carbide (Ti3C2) MXenes onto the electrospun mats using poly(vinylidene fluoride) (PVDF) as the base polymer. The fibrous membrane was further modified with the inclusion of zinc oxide (ZnO) and tungstite (WO3·H2O) nano/microstructures via annealing and hydrothermal approaches. Through these strategic interfaced morphological developments in novel Ti3C2/ZnO/WO3·H2O heterostructures, our findings reveal enhanced wettability and charge-segregation desirable for promoting oil-water separation and photoreactivity, respectively. The superhydrophilic hierarchical architectures offer optimal separation potential for stable oil-water emulsions with a higher flux. Additionally, when exposed to LED light, the composite membrane demonstrated an enhanced photocatalytic capacity for the removal of organic contaminants. This simple, inexpensive, and eco-friendly approach may thus promote the route for the fabrication of 2D MXene-based multifunctional membranes for effective treatment of complex oily wastewater.

PH-Responsive superhydrophobic fabric based on AgNP/copolymer composites for controllable oil–water separation

pH-Responsive superhydrophobic fabric based on AgNP/copolymer composites for controllable oil–water separation

Superhydrophobic porous organic cage decorated melamine sponge for efficient oil-water separation

Superhydrophobic porous organic cage decorated melamine sponge for efficient oil-water separation

Regulation of Oil/Water Separation Using Pyridinium-Based Poly(ionic liquid)s with Prewetted Induced Responsive Transition.

The development of affordable, intelligent dual-separation technology is crucial for the treatment of oil-water mixtures. Pyridinium-based poly(ionic liquid)s (PILs), designed using molecular theory, exhibit unique switching wettability properties, making them ideal for use in both aqueous and oily environments. By prewetting the material's surface with water or oil, the targeted separation of these components becomes feasible. PILs are synthesized through the cross-linking of [Pyr]Cl with various cross-linkers and auxiliary agents. Studies on the wetting mechanism of these materials have identified bursting pressure and surface structure as key factors influencing their wetting properties. They exhibit hydrophilic and lipophilic properties in air, hydrophobic properties under oil, and oleophobic properties under water, achieving a 99% separation efficiency. A reusability study demonstrated maintenance of 90% efficiency after 10 cycles, highlighting their sustained high performance. This research presents promising avenues for the application of PIL-based materials in oil-water separation, environmental remediation, and industrial processing.

Highly Efficient Production of Mullite Sponges with Ultralight and Superelastic via Solution Blow Spinning for Oil–Water Separation

Highly Efficient Production of Mullite Sponges with Ultralight and Superelastic via Solution Blow Spinning for Oil–Water Separation

Anisotropic Microparticles with a Controllable Structure via Soap-Free Seeded Emulsion Polymerization.

Anisotropic particles have a wide range of applications in materials science such as emulsion stabilization, oil-water separation, and catalysis due to their asymmetric structure and properties. Nevertheless, designing and synthesizing large quantities of anisotropic particles with controlled morphologies continue to present considerable challenges. In this study, we successfully synthesized anisotropic microspheres using a soap-free seed emulsion polymerization method. This approach combines the benefits of seed emulsion polymerization with emulsion interfacial polymerization. By varying the concentrations of dissolved polymeric monomers, 3-methacryloyloxypropyltrimethoxysilane (MPS), and the initiator of potassium persulfate (KPS), different shapes of bowl, cap, and three-sided concave particles were obtained in surfactant-free aqueous solutions, simplifying the post-treatment process. The cap particles are Janus particles with good emulsion stability to toluene/water emulsions over 30 days. The catalytic degradation of 4-nitrophenol (4-NP) was investigated after loading silver nanoparticles on the surface of the particles by in situ deposition. The anisotropic particles obtained in this work have potential applications in emulsion stabilization and catalysis.

Facile preparation of marine carrageenan hydrogel-coated steel mesh with superhydrophilic and underwater superoleophobic performance for highly efficient oil-water separation.

The discharge of oil-laden wastewater from industrial processes and the frequent occurrence of oil spills pose severe threats to the ecological environment and human health. Membrane materials with special wettability have garnered attention for their ability to achieve efficient oil-water separation by leveraging the differences in wettability at the oil-water interface. These materials are characterized by their simplicity, energy efficiency, environmental friendliness, and reusability. Among them, superhydrophilic-underwater superoleophobic membranes inspired by biomimetic fish scale structures have become a focal point of oil-water separation research due to their ability to repel oil contaminants effectively and maintain self-cleaning properties during the separation process. In this study, a stainless steel microporous two-dimensional metal mesh was employed as the substrate, coated with a carrageenan solution, and gelled in situ using sodium periodate as a crosslinking agent to fabricate a membrane with oil-water separation capabilities. The robust hydrophilicity of the carrageenan hydrogel imparts the coated stainless steel mesh with superhydrophilicity and underwater superoleophobicity (underwater oil contact angle ≥ 158°), along with excellent antifouling properties and recyclability. Experimental results demonstrate that the membrane achieved separation efficiencies of 98.87%, 98.08%, 98.14%, and 97.98% for silicone oil, canola oil, cyclohexane, and liquid paraffin, respectively, with a water flux of 1380.75L/m2·h. Remarkably, the membrane retained its initial separation efficiency even after 20 cycles. Additionally, the hydrogel exhibited exceptional stability under highly alkaline conditions, making it suitable for the treatment of complex oil-contaminated wastewater. PRACTITIONER POINTS: This study extracted a biocompatible and renewable hydrogel from marine red algae for application in oil-water separation. A superhydrophilic/underwater superoleophobic oil-water separation membrane was developed based on biomimetic fish scale structures. The membrane exhibited exceptionally high separation efficiency under pure gravity-driven conditions. The resulting material exhibits excellent oil repellency, self-cleaning capability, and recyclability.

Enhancing interfacial regulation by S/O co-doping for effective oil–solid and oil–water separation at room temperature

Enhancing interfacial regulation by S/O co-doping for effective oil–solid and oil–water separation at room temperature

Robust shape memory chlorobutyl rubber/boron nitride polymer nanocomposites for oil-water separation application

BackgroundBoron nitride (h-BN), an excellent 2D material finds exceptional applications in various fields owing to its unique characteristics including excellent hydrophobicity. Incorporation of boron nitride in polymer matrices is a captivating strategy by the scientific community to tune the properties of polymer. Interestingly, the possibilities of incorporating h-BN in chlorobutyl rubber (CIIR) matrix has never been considered and tried till now. Moreover, the use of CIIR to create a clean environment and reduce water pollution is an unexplored area even though the CIIR rubber possess excellent barrier properties. MethodsIn this work, two techniques were used for the fabrication of BNNS/CIIR nanocomposite. We exfoliated h-BN via chemical exfoliation method and tried the reinforcement of CIIR with BNNS via solution intercalation method. Shape memory analysis was performed with the help of stearic acid and oil-water separation analysis was achieved through an easy experimental technique. Significant findingsEnhanced mechanical strength of 11.57 MPa, improved thermal degradation temperature and char yield, higher glass transition temperature of -45.98° were observed for BNNS/CIIR nanocomposite reinforced with higher BNNS loading owing to the uniform distribution and better intercalation of BNNS in CIIR. Excellent shape memory was exhibited by CIIR matrix when reinforced up to 5 g BNNS. In addition, the nanocomposites displayed excellent ability to perform oil-water separation with increase in BNNS loading owing to the good hydrophobic character of h-BN and inherent barrier properties of CIIR. Thus, the study proved successful towards the fabrication of advanced CIIR nanocomposites with excellent shape memory and oil water separation efficiency.