Superhydrophobic and Superlipophilic Low Density Polyethylene/Styrene–Butadiene Rubber Thermoplastic Vulcanizate Film for Pressure-Responsive Continuous Oil–Water Separation

In recent years, with the continuous discharge of wastewater, which has caused serious environmental pollution, it is a task to separate oil or water from wastewater. Therefore, an efficient and low-cost oil–water separation method is needed to separate the oil–water mixture. Here, a superhydrophobic/superoleophilic low density polyethylene/styrene-butadiene rubber (LDPE/SBR) thermoplastic vulcanizate (TPV) film (oil contact angle of 0° and water contact angle of 161.1° ± 1.7°) is prepared using an etched aluminum foil as a template and applied to a laboratory-assembled oil–water separation device, which is a new method for oil–water separation via a pressure response valve. The LDPE/SBR TPV film is rolled up and stuffed into the through-valve, and the gap between the films is used as the pressure response channel for oil and water separation, thus achieving oil and water separation. When the film gap is 25 or 50 µm, the separation efficiency of TPV film is greater than 99% with the variation of external pumping force, indicating that this method can achieve complete oil–water separation under a suitable external pumping force. This functional TPV film has good recyclability, environmental stability, chemical stability, mechanical durability, as well as thermal stability, which makes it have great application potential.     

Stable superhydrophobic surface based on low‐density polyethylene/ethylene‐propylene‐diene terpolymer thermoplastic vulcanizate

Stable superhydrophobic surface based on low‐density polyethylene (LDPE)/ethylene–propylene–diene terpolymer (EPDM) thermoplastic vulcanizate (TPV) was successfully fabricated by using etched aluminum foil as template. The etched aluminum template consisted of micropores and step‐like textures, was obtained by the metallographic sandpaper sanding and the subsequent acid etching. The surface morphology and hydrophobic properties of the series molded TPV surfaces were researched by varying the weight ratio of the LDPE/EPDM TPV. The superhydrophobic LDPE/EPDM TPV surfaces exhibited the microstructures consisting of step‐like textures obtained via molding with etched aluminum template and a large number of fiber‐like structures resulted from the plastic deformation of LDPE matrix. The obtained TPV (LDPE/EPDM weight ratio = 70/30) surface exhibited the remarkable superhydrophobicity, with a contact angle of 152.0° ± 0.7° and a sliding angle of 3.1° ± 0.8°. The molded TPV surface had excellent environmental stability when the pH of water solution was in the range of 1 to 14; moreover, the surface also showed the excellent resistance to various organic solvents. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46241.     

One-pot fabrication of robust hydrophobia and superoleophilic cotton fabrics for effective oil-water separation

A one-pot sonochemical irradiation method was developed for the fabrication of superhydrophobic and superoleophilic cotton fabric from a solution consisting of branched silica nanoparticles and tetraethoxysilane-dodecyltrimethoxysilane sol. The silica/sol-coated cotton fabric could be wetted by liquids of low surface tension, but was water repellent with a water contact angle of 159 ± 1.2° and water shedding angle of 6 ± 0.8°. The as-prepared cotton fabric could be used as effective materials for the separation of oil from water with separation efficiency as high as 98.2% and maintained separation efficiency above 94% after 30 separation cycles for the kerosene-water mixture. Moreover, the superhydrophobic and superoleophilic cotton fabric could maintain stable superhydrophobicity after treatment with strong acidic and alkali solutions, and harsh mechanical damage. Therefore, this reported robust superhydrophobic cotton fabric exhibits encouraging practical application for oil-water separation.     

Robust,fluorine-free and superhydrophobic composite melamine sponge modified with dual silanized SiO_2 microspheres for oil–water separation

Massive oily wastewater discharged from industrial production and human daily life have been an urgent environmental and ecological challenge. Superhydrophobic materials have attracted tremendous attention due to their unique properties and potential applications in the treatment of wastewater. In this study, a novel superhydrophobic/superoleophilic composite melamine sponge modified with dual silanized Si O_2 microspheres was fabricated simply by a two-step sol–gel method using vinyltriethoxysilane and hexadecyltrimethoxysilane as functional agent, which exhibited a water contact angle of 153.2° and a water sliding contact angle of 4.8°. Furthermore, the composite sponge showed the excellent oil adsorption performance and the compressive elasticity reaching up to 130 g·g~(-1) of dichloromethane and 33.1 k Pa of compressive stress. It was worth noting that the composite sponge presented the excellent separation efficiency(up to 99.5%) in the processes of continuous oil/water separation. The robust superhydrophobic composite melamine sponge provided the possibility with the practical application for oil–water separation.     

A novel composite coating mesh film for oil-water separation

Polytetrafluoroethylene-polyphenylene sulfide composite coating mesh film was successfully prepared by a simple layered transitional spray-plasticizing method on a stainless steel mesh. It shows super-hydrophobic and super-oleophilic properties. The contact angle of this mesh film is 156.3° for water, and close to 0° for diesel oil and kerosene. The contact angle hysteresis of water on the mesh film is 4.3°. The adhesive force between the film and substrate is grade 0, the flexibility is 1 mm and the pencil hardness is 4H. An oil-water separation test was carried out for oil-contaminated water in a six-stage superhydrophobic film separator. The oil removal rate can reach about 99%.     

耐腐蚀超疏水超亲油不锈钢网的制备及其在油水分离过程中的应用

以不锈钢网为基底,通过化学刻蚀法制备微米级粗糙表面,通过一步浸泡法将st9ber法制得的疏水亲油纳米Si O2颗粒沉积到粗糙的不锈钢网表面,制备了具有微纳二级粗糙结构的超疏水超亲油不锈钢网。利用扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FT-IR)和接触角测量仪(CA)表征了超疏水超亲油不锈钢网的表面形貌、化学组成和润湿性能,并将其用于油水分离过程中。结果表明,疏水亲油纳米Si O2颗粒成功的沉积到不锈钢网表面;水滴在超疏水超亲油不锈钢网上的接触角最大为151°,煤油的接触角为0°;制备的超疏水超亲油不锈钢网不仅能高效的分离不同种类油和水的混合物,还能高效的分离油和腐蚀性液体(强酸或强碱水溶液)的混合物,其耐腐蚀特性可满足复杂环境下的油水分离要求。     

Fabrication of durable superhydrophobic and superoleophilic cotton fabric with fluorinated silica sol via sol–gel process

Superhydrophobic and superoleophilic cotton fabric was successfully prepared with fluorinated silica sol via a facile sol–gel method. A fluorinated polymeric sol–gel precursor (PHFBMA-MTS) was synthesized via free-radical polymerization by using hexafluorobutyl methacrylate (HFBMA) in the presence of (3-mercaptopropyl)trimethoxysilane (MTS) as the chain transfer agent, which led to the formation of fluoropolymer with alkoxysilane end groups. Then the fluorinated silica sol was prepared by introducing PHFBMA-MTS as the co-precursor of tetraethylorthosilicate (TEOS) in the sol–gel process with ammonium hydroxide as the catalyst, which was then used to fabricate superhydrophobic and superoleophilic fabric coatings through a simple dip-coating method. The coated fabrics showed superhydrophobic property with a high water contact angle of 154.1° and superoleophilic property with an oil contact angle of 0°. Moreover, the coated fabrics still kept superhydrophobicity even after ultrasonic treatment, as well as for organic solutions, acidic solutions. Thus, the coated fabrics were successfully applied to separate oil–water mixture with separation efficiency up to 99.8%. More importantly, the separation efficiency had no significant change after 20 cycles of oil–water separation. These present a simple, low-cost, and durable approach to achieve industrialized application of coated fabrics in oil–water separation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47005.     

Superhydrophobic/superoleophilic micro/nanostructure nickel particles for oil/water mixture and emulsion separation

Nowadays, developing reusable and highly efficient materials for separating nano/micro-sized oil droplets from oil/water mixture and emulsion remains very challenging. Herein, hedgehog-like micro/nanostructure nickel particles were fabricated via a hydrothermal route. Thanks to its unique morphology, the octadecyltrichlorosilane (ODTS)-modified nickel particles show suitable superhydrophobicity/superoleophilicity properties with water contact angle, oil contact angle, and contact angle hysteresis values of 169.17° ± 2.13°, 0°, and 2.32°± 0.34°, respectively, making the potential sorbent for oil/water separation. The dense narrow thorns of superhydrophobic/superoleophilic nickel particles help the maximum scattering of particles on the surface and in the solutions. Hence, superhydrophobic/superoleophilic nickel particles demonstrated outstanding sorption capacity ranging from 3.86 to 5.27 (g/g) for a wide range of organic solvents and oils. Also, sorption capacities were retained even after 10 sorption cycles. Additionally, sorption capacities remain steady under acidic, alkaline, and high-saline conditions, indicating the high resistance in the harsh media. More importantly, ODTS-modified particles could also be used in oil/water emulsion separation with efficiencies of higher 99%. The appropriate resistance of hedgehog-like micro/nanostructure nickel particles to various environmental conditions as well as reusability and recyclability provides good opportunities for industrial applications of oil uptake from the oil/water mixture and emulsion.     

Vertically zeolitic imidazolate framework-L coated mesh with dagger-like structure for oil/water separation

The novel functional superwettable materials for high-efficiency oil/water separation are urgently required due to oil pollution in water body caused by oil tanker accidents, seabed oil production, and oil from refineries and petrochemical plants. Here, the superhydrophobic and superoleophilic zeolitic imidazolate framework-L (ZIF-L) mesh with antimicrobial effect was successfully fabricated by in-situ growth, composed of vertically ZIF-L with micro-/nanodagger-like structure and exhibited the water contact angle of 155.4 ± 1.8° and the oil contact angle of 0° in air. Furthermore, ZIF-L was verified to have an excellent antimicrobial activity, which endowed ZIF-L mesh with good antimicrobial performance. ZIF-L mesh provided a permeation flux with 1.75 × 10⁵ L m⁻² hr⁻¹ and 99.7% separation efficiency after 10 cycles operations for water mixtures with isooctane and presented optimal stability. Accordingly, the results demonstrated that ZIF-L as a new material shows an attractive applied promise for oil/water separation in industry.     

Facile fabrication of robust superhydrophobic cotton fabrics modified by polysiloxane nanowires for oil/water separation

The removal of oil and organic pollutants from water is highly desired due to increasing industrial oil-contaminated wastewater, as well as frequent oil spill accidents. In this paper, superhydrophobic and superoleophilic fabrics were facilely fabricated for oil/water separation application via in situ growth of polysiloxane nanowires on cotton fabrics. The polysiloxane nanowires were immobilized on the cotton fabrics through a self-assembly process of alkylsilane on the microfibers of fabrics. The combination of the hierarchical structure and the low-surface-energy polysiloxane nanowires greatly contributed to the superhydrophobicity of the fabrics. Furthermore, the superhydrophobicity remained even after they were exposed to different chemicals for 72 h and strong ultraviolet irradiation and repeated abrasion, indicating excellent stability. More importantly, the as-prepared cotton fabrics were successfully used for separating various oil/water mixtures by a solely gravity-driven process with high separation efficiency and desirable durability. The cotton fabrics are commercially available, low-cost, and environmentally friendly materials, and thus such superhydrophobic and superoleophilic cotton fabrics could be very attractive for oil/water separation and oil spill cleanup when high flexibility, strength, and chemical resistance are taken into account.     

Oil‐absorbent polyurethane sponge coated with KH‐570‐modified graphene

Polyurethane (PU) sponge has become a preferred oil adsorbent in recent oil‐spill accidents. To make the sponge superhydrophobic and superoleophilic, this study used graphene (GN), which was modified with γ‐methacryloxypropyl trimethoxy silane (KH‐570), to coat the PU sponge (called the KH–GN sponge). This study showed the best loading capacity (11.96%) of the KH‐570‐modified GN on the sponge. The contact angles of the KH–GN PU sponge were 161° for water and 0° for soybean, diesel, and pumping oil. It had good selectivity for oil over water, and the KH–GN sponge achieved adsorption equilibrium within a few seconds. The absorption capability of the KH–GN sponge was up to 39 times greater. Additionally, the KH–GN PU sponge could be reused for oil–water separation for more than 120 cycles without losing its superhydrophobic and superoleophilic properties. Therefore, the sponge prepared in this study could be a desirable material for the cleanup of oil spills. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41821.     

A polypropylene melt-blown strategy for the facile and efficient membrane separation of oil-water mixtures

Porous materials with selective wettability and permeability have significant importance in oil-water separation, but complex fabrication processes are typically required to obtain the desired structures with suitable surface chemistry. In this work, an industrial melt-blown strategy that utilized commercially available polypropylene (PP) was used for the large-scale fabrication of superhydrophobic/superoleophilic membranes with staggered fabric structures. These membranes could readily separate different oils including pump oil and crude oil from various aqueous solutions such as strongly acidic, alkaline, and saline media. In addition, the separation efficiencies of these membranes exceeded 99%, and they could remain functional even after exposure to corrosive media. We anticipate that this work will further the design of membranes and enhance their applicability in oil-water separation, and provide researchers and engineers with a more effective tool for performing challenging separations and mitigating pollution.     

基于HDPE/EPDM TPV的超疏水表面的构建及性能

以高密度聚乙烯(HDPE)/三元乙丙橡胶(EPDM)热塑性硫化胶(TPV)为原材料,采用金相砂纸为模板,通过模压法在TPV表面构建出超疏水表面。FE-SEM的观察表明,以金相砂纸为模板可在TPV表面获得具有较高保真度的微米级粗糙结构,模压过程中TPV表面发生的塑性变形,使得TPV表面具有比砂纸表面更为复杂的粗糙结构;润湿性测试结果表明,基于TPV的粗糙表面具有良好的疏水性,当磨料目数高于W14号砂纸时,模压后TPV表面与水的接触角可超过150°,且滚动角在10°以内,符合Cassie模型;采用W10号砂纸为模板制备的TPV表面具有最佳的超疏水性能。     

Halloysite nanotube-based superhydrophobic foam for highly efficient oil/water separation

Oil/water separation is a worldwide concern because of the emissions of oil contaminated wastewater and increasing number of oil spill accidents in recent years. Materials with superhydrophobicity and superoleophilicity provide a new strategy to solve such problems, which allow organic solvents to pass through freely while repelling water. Herein, the porous foams with superhydrophobicity and superoleophilicity were prepared successfully through a facile low-temperature sintering method, in which the halloysite nanotubes (HNTs), polyvinylidene fluoride (PVDF) and sodium chloride were used as the raw materials. Among them, HNTs constructed the rough surface in micro-/nano-scale and sodium chloride served as the sacrifice template. The superhydrophobic surface was achieved via the synergistic effect between the rough surface and PVDF with the low surface energy. The foam showed good water repellency (water contact angle, CA: 156.0 ± 0.1°) and superoleophilic properties, which could selectively absorb organic solvents from the mixture solution with water. Moreover, the foam exhibited high separation efficiencies for a variety of oil/water mixed solutions with excellent cycling stability, which make it a promising material for practical oil/water separation.     

超亲水天然多酚改性膜的制备及其油水分离性能

为研发绿色环保、制备工艺简单的油水分离材料，以单宁酸(TA)和聚乙二醇(PEG)为改性剂，聚偏氟乙烯(PVDF)膜为基底，通过简单浸渍法，制备了超亲水复合膜(TAPE膜)。采用SEM、AFM、FTIR、XPS和接触角测定仪对TAPE膜进行了表征和分析，并考察了TAPE膜的油水分离性能、耐磨性能和稳定性。结果表明，TAPE膜具有多孔微纳米粗糙结构，当TA含量为蒸馏水质量的1.75%时，该膜的水接触角和水下油接触角分别为0°和156°，表现出超亲水性和水下超疏油性。在0.09 MPa工作压力下，TAPE膜分离水包油乳液的膜通量为1146.4 L/(m²·h)，是原始PVDF膜的30倍，该膜对油水混合液和水包油乳液的分离效率均可达99.9%。此外，TAPE膜具有良好的稳定性，膜表面经砂纸(320目)磨损(100 g载重)25次后水接触角仍高达152°。     

The effect of superhydrophobicity of prickly shape carbonyl iron particles on the oil-water adsorption

The separation of oil spillage from marine environments has been discussed as a global concern. Recyclable superhydrophobic magnetic particles with micro-nano structures have been considered as a potential providing a safe, practical, and easy method for removing the oil from oil-water. In this research, the hydrophobicity of magnetic particles was enhanced to achieve the maximum adsorption capacity. For this purpose, reacted carbonyl iron (CI) with glucose was reacted with stearic acid under different condition of temperature, time, and concentration. Analytical tests were performed to confirm the reaction of stearic acid with CI@glucose. The prickly shape created on the surfaces of magnetic particles led to achieving the maximum superhydrophobicity. In this connection, the optimized superhydrophobic particles based on the maximum obtained water contact angle (WCA) of 169° at 75 °C, and 3.5 h and 10% concentration of stearic acid were selected for the oil-water separation. The results revealed that the superhydrophobic particles had acceptable stability within pH range of 2–12. The adsorption capacity of the modified particles for hexane, silicone oil, gasoline, and kerosene was 4.1, 2.5, 3.1, and 3.7 g/g, respectively, with a high adsorption efficiency ( > 99.7%) in the oil-water mixture. After ten cycles of using these particles, the adsorption capacity range was 2 to 4 g/g regardless of the number of recycling times, and no significant change was observed in the contact angle.     

Robust superhydrophobic/superoleophilic sponge for efficient removal of oils from corrosive aqueous solutions

Separation of oil/water mixtures became a significant worldwide issue because of the frequent oil leakage incidents in marine. Herein, a robust superhydrophobic/superoleophilic porous polyurethane (PU) sponge was fabricated just by simple one-step procedure of dip-coating of OTS. The modified PU sponges possessed a superhydrophobicity with water contact angles (CAs) exceeding 156°. The as-prepared sponge exhibited high oil adsorption capacity, robust recyclability for oil/water separation even under strong acid, alkali and salt conditions. Furthermore, when the as-prepared sponge was connected to a vacuum system, the sponge could efficiently remove up to 100?mL kerosene within 25?s under a vacuum of 30?kPa. The simple fabrication process and favorable durability make the sponge a promising candidate for using in a large-scale marine oil leakage clean-up.     

A facile approach in fabricating superhydrophobic and superoleophilic poly (vinylidene fluoride) membranes for efficient water–oil separation

New preparation strategies for films that exhibit separation of emulsified oil/water mixtures through a simple, practical, and cost‐effective method are highly desirable. Herein a poly (vinylidene fluoride) membrane with superhydrophobic and superoleophilic surface had been successfully fabricated via a facile dip‐coating process. As‐prepared membrane exhibits good stability of wettability and can be applied for oil and water mixture separation. After cycles, the membranes still keep a relatively high flux, which indicates their great potential for practical applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42077.     

One-step fabrication of superhydrophobic and superoleophilic cigarette filters for oil-water separation

To develop a simple and efficient way to recycle used cigarette filters, we report on a one-step method for preparing superhydrophobic and superoleophilic cigarette filters for oil–water separation. The robust coating layer on the surface of the cellulose acetate fiber, along with the inherent rough texture of the cigarette filter, could lead to its surface that displayed superhydrophobicity and superoleophilicity. Water droplets can retain in spherical shapes on the modified cigarette filters, while oils were immediately absorbed by the cigarette filters with high absorption capacity. As a result, free oil–water mixtures were separated with efficiency of above 98.0% by the driving force of gravity, and water-in-oil emulsion was also separated with a promising flux of about 2500 L m^?2 h^?1. The purity of oil for the tested emulsion was above 99.96%, indicating extremely high separation efficiency. This method for the fabrication of the superhydrophobic and superoleophilic cigarette filters would be a good candidate for recycling the solid wastes and developing an economic oil–water separation material to meet emerging needs in practical applications.     

Superhydrophobic–superoleophilic electrospun nanofibrous membrane modified by the chemical vapor deposition of dimethyl dichlorosilane for efficient oil–water separation

Superhydrophobic and superoleophilic functionalized electrospun poly(vinylidene fluoride) (PVDF) membranes with water repellence, breathability, and oil-sorption and oil–water separation properties were achieved with a combination of an electrospinning technique and the chemical vapor deposition of dichlorodimethyl silane. The samples were laterally characterized by scanning electron microscopy, atomic force microscopy, water contact angle measurement, and Fourier transform infrared spectroscopy. The maximum water contact angle value was 152.0 ± 2.5° for the PVDF nanofibrous membranes with 500 μL of deposited silane (PMS2) obtained under certain conditions. The PMS2 membranes showed 100.0, 93.7, 23.3, 35.0, and 100.0% separation efficiencies for n-hexane, kerosene, crude oil, frying oil, and toluene, respectively. The understudy membrane exhibited reasonable waterproofness and remarkable breathability (water vapor transition rate = 215.21 g/m².h). Moreover, the superhydrophobic and superoleophilic nanofibrous membranes also showed good reusability, stability, moderate water-repellent properties, breathability, antifouling properties, and oil–water separation ability after several cycles. These properties confirmed potential in feasible applications, including protective cloths and in the purification of oil-polluted water. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47621.