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.     

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.     

超疏水-超亲油材料在油水分离中的研究进展

综述了超疏水-超亲油油水分离材料的研究进展及其在油水分离中的应用。首先介绍了油水分离材料的特殊润湿性的基本理论和设计理念,主要包括Young方程、Wenzel模型、Cassie模型以及制备油水分离材料的两种途径。然后全面介绍了金属网膜类、纺织品类、合成膜类等二维结构的油水分离材料,以及海绵、泡沫、气凝胶等三维网络状类油水分离材料和智能型油水分离材料。最后总结了目前在油水分离这一领域存在的一些问题,主要是油水分离的基本机制和理论研究不够完善,并指出开发和研究能够分离特殊油品的材料以及智能响应性可控的油水分离材料仍然是一大挑战。     

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.     

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。     

Super-hydrophobic and super-lipophilic functionalized graphene oxide/polyurethane sponge applied for oil/water separation

Nowadays, oil spills have led to a serious environmental crisis of the world. To deal with this problem, inspired from super-hydrophobic lotus leaf, this study fabricated super-hydrophobic and super-lipophilic functionalized graphene oxide/polyurethane(FGP) sponge by a simple and inexpensive dip coating method. The resulting FGP sponge was characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and water contact angle. The results expressed that FGP sponge exhibited a similar surface structure to that of a lotus leaf, and possessed the super-hydrophobic characteristic with the water contact angle(WAC) of 152°±1°. The absorption capacity and reusability were also investigated. It can be seen that, the FGP sponge can remove a wide range of oils and organic solvents from water with good absorption capacities(up to 35 times of its own mass). Significantly, after 10 cycles the absorption capacity of the oils and organic solvents was higher than 90%for the reused FGP sponge, demonstrating the good reusability of the FGP sponge. Therefore, this study probably provided a simple way to remove the pollutions of oil spills and toxic organism from water.     

Superhydrophobic and photothermal sponge for effective oil/water separation and solar-assisted recovery of viscous oil

With the occurrence of offshore oil spills, the recovery of viscous oil continues to be a significant issue. The multi-functional sponge with superhydrophobic, absorption of high viscosity oil is an effective approach to settle this problem. In this work, the melamine-formaldehyde (MF) sponge was the backbone and doped with polydopamine (PDA) to mimic mussels. Subsequently, candle soot nanoparticles (CS) and polydimethylsiloxane (PDMS) were applied to modify the MF sponge into a superhydrophobic sponge (P-CS-PDA@MF) (WCA = 153.56°). The P-CS-PDA@MF sponge showed good absorption properties for many oils and organic solvents (33.87–78.90 times of its own weight). In addition, the P-CS-PDA@MF sponge also showed outstanding chemical stability, low density (0.013 g/cm³), emulsion-breaking ability and flame retardancy. More interestingly, the P-CS-PDA@MF sponge showed superior photothermal conversion capability, the temperature of it increased to approximately 91°C within 100 s under simulated sunlight from room temperature (about 25°C), and the sorption capacity of viscous oils was significantly increased. Moreover, the P-CS-PDA@MF sponge exhibited a high efficiency (over 97%) for separating viscous oils/water mixtures with the aid of sunlight. This versatile and efficient multifunctional P-CS-PDA@MF sponge via a simple and low-cost way shows promising prospect in oily wastewater treatment and water ecosystem remediation.     

Polymeric materials with switchable superwettability for controllable oil/water separation: A comprehensive review

Oily water treatment has become an urgent need in our daily life because of its harmful potential to the ecological system. In recent years, functional materials with superwetting or superantiwetting property have experienced a rocketing development due to their applications in various areas, including self-cleaning, anti-icing, printing, water collection, liquid transfer, oil/water separation, and so on. In this regard, recent advances in polymer science hold the promise of fine-tuning the composition and morphology for a targeted design to meet the requirements in specific application fields. This review focused on polymeric materials, especially smart polymers, for controllable oil/water separations. Starting from the fundamental theories and criteria related to the separation mechanisms, different stimuli including pH, solvent, ions, chemicals, temperature, photo, electric, pressure, and dual stimuli for triggering smart oil/water separation processes were summarized. Highlights on polymer types, polymer synthesis approaches, separation materials fabrication method, as well as separation performances were present. Current limitations and future perspective were also given. This review aims to offer deep insights into polymer-based interfacial science and provide guidance for the fabrication of smart polymeric surfaces for oily water separation.     

聚结技术及其乳化油水分离性能

聚结分离是一种利用油、水两相对材料浸润性的不同而实现乳化液滴聚结长大并最终通过重力沉降实现油水分离的物理方法,这种方法结构可控性好、分离效率高、运行成本低,是乳化油水分离领域的研究热点。本文首先对聚结分离方法进行详细阐述,介绍了聚结分离原理和影响因素;总结了近年来国内外学者对聚结材料表面改性和修饰等方面的研究。通过调控聚结材料的表面具有特殊浸润性,可显著提高油水分离效率;系统介绍聚结分离器的分类及其应用。最后阐述了聚结分离技术在石油化工领域的应用。本文对聚结分离技术进行展望,指出可以进一步研究实际液滴聚结过程和分离效果影响因素,应深入研究分离器在乳化油水分离过程中液滴聚结行为、机理、控制机制将是研究的重点。     

Superhydrophobic,mechanically flexible and recyclable reduced graphene oxide wrapped sponge for highly efficient oil/water separation

Water pollution has become an urgent issue for our modern society, and it is highly desirable to rapidly deal with the water pollution without secondary pollution. In this paper, we have prepared a reduced graphene oxide (RGO) wrapped sponge with superhydrophobicity and mechanically flexibility via a facile low-temperature thermal treatment method under a reducing atmosphere. The skeleton of this sponge is completely covered with RGO layers which are closely linked to the skeleton. This sponge has an abundant pore structure, high selectivity, good recyclability, low cost, and outstanding adsorption capacity for floating oil or heavy oil underwater. In addition, this sponge can maintain excellent adsorption performance for various oils and organic solvents over 50 cycles by squeezing, and exhibits extremely high separation efficiencies, up to 6 × 10⁶ and 3.6 × 10⁶ L·m^–3·h^–1 in non-turbulent and turbulent water/oil systems, respectively. This superhydrophobic adsorbent with attractive properties may find various applications, especially in large-scale removal of organic contaminants and oil spill cleanup.

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Fabrication of supported carbide-derived-carbon membrane by two phases of interfacial polymerization for oil/water separation

As recovery of clean and potable water from oil contaminated produced water lies at the heart of petroleum industry, various membranes have been developed to address this challenge. Given the salient features of high thermal and chemical stabilities, ceramic membranes possess huge potential for recovering potable water from produced water. A new CDC/PA@Ceramic membrane (carbide-derived carbon/polyamide on Al₂O₃ ceramic support) was fabricated by depositing carbide derived carbon (CDC) on alumina support through two phases of interfacial polymerization using piperazine and 3,5-diaminobenzoic acid crosslinked through terephthaloyl chloride. The merits of the fabricated membrane were thoroughly characterized by several characterization techniques including Field emission scanning electron microscopy, Energy-dispersive X-ray spectroscopy, Elemental mapping, Powder X-ray diffraction and Attenuated total reflectance Fourier transform infra-red spectroscopy. The CDC/PA@Ceramic membrane showed promising performance in terms of permeate flux and separation efficiency for oil/water emulsion. The separation efficiency remained >96% for all studied emulsion-concentrations (250 ppm, 125 ppm and 67.5 ppm). The highest separation efficiency was >98% with a feed concentration of 67.5 ppm of oil/water emulsion. The highest pure water permeate flux reached 250 L/m².h at 4 bar. The long-term stability test showed that the CDC/PA@Ceramic membrane remained stable for elongated time of 720 min with constant separation efficiency of >96% and permeate flux of 58 L/m².h at 2 bars. All results were validated by visual inspection, fluorescence spectrophotometry and optical microscopy of the feed and permeate throughout the membrane performance tests. The CDC/PA@Ceramic membrane can be a potential candidate for recovering precious water from the waste produced water.     

超亲水SiO2修饰膜的构建及其油水乳液分离性能

采用硅溶胶和多巴胺作为修饰剂,通过一步反应在微孔聚丙烯膜(MPPM)表面构建了SiO₂修饰层。利用FTIR、ESEM和EDX对膜进行了表征,发现膜表面SiO₂颗粒分布非常均匀。水/油接触角及纯水通量实验结果表明,修饰膜具有超亲水性及水下超疏油性,透水能力强,水通量大[在0.1 MPa时,水通量高达(5100±500)L·m^-2·h^-1]。油水乳液分离结果表明,修饰膜能有效分离油水乳液,在0.05 MPa时,油水乳液水通量达2830 L·m^-2·h^-1,油截留率达99.8%以上,即使过膜压力增大到0.15 MPa,油截留率也能保持在99%以上,且膜表面的油污可用水清洗除去,展现出很好的应用前景。     

Preparation of PAN@PU coaxial electrostatic spun nanofibers for oil/water separation

Coaxial electrostatic spinning (co-electrostatic spinning) technology has greatly expanded the versatility of the preparation of core–shell polymer nanofibers and has found a wide range of applications in the environmental and biological fields. Here we present a method for the preparation of coaxial nanofibers using polyacrylonitrile (PAN) and polyurethane (PU) as raw materials. It was found that the tensile strength ranges from 2.14 to 4.07 MPa with the increasing spinning speed of the nucleated PU layer, and the elongation at break was up to 95.09% for M_6:4, which was three times higher than that of the original M_PAN (30.54%), and the toughness of the nanofiber film was also significantly improved. Finally, the oil/water separation capacity of the coaxial nanofiber membrane was investigated, and the results showed that the separation fluxes for various oil compounds ranged from 2380.18 to 3130.17 L·m⁻²·h⁻¹, with separation efficiencies above 99%. This study not only investigates the effect of different flow rates of core (PU)/shell (PAN) on the performance of coaxial electrostatic spun nanofiber membranes, but also provides a new insight into the coaxial electrostatic spinning process.     

Tuning the morphology of PVDF membranes using inorganic clusters for oil/water separation

Polyvinylidene fluoride (PVDF) membranes with modified membrane morphology were prepared by phase inversion process using iron alkoxide as a novel pore-forming additive (PFA). Higher pure water flux was observed for PVDF/PFA (iron alkoxide) membranes treated with 5% HCl, due to higher porosity produced by the leaching out of the iron alkoxide additive. The untreated membrane containing 0.04% iron alkoxide showed ~99% efficiency oil removal from a surfactant-stabilized oil–water emulsion. After acid treatment, there was a slight decrease in the rejection efficiency (~96.5%); however, this membrane still exhibited the highest emulsion flux. The fouling propensity of the membrane with 0.04 wt % iron alkoxide tested in a crossflow condition decreases indicating a lower amount of oil adsorbed onto the surface and a greater flux recovery ratio. The treated membranes showed appreciable anti-biofouling property when the membranes were challenged with Escherichia coli and Bacillus subtilis obtained from freshwater and/or seawater. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47641.     

疏水性油水分离膜及其过程研究进展

油水分离是治理含油废水和含水油液的重要工业过程。本文概括了疏水性油水分离膜的类型与制备方法,包括常规分离膜和高度疏水/超亲油分离膜。前者为常规微滤、超滤及纳滤过程用膜;后者由构筑高度疏水（水滴接触角≥120°）表面方法得到,形式有金属网膜、纤维膜、滤纸、复合膜及不对称膜,其为制备耐污染的疏水性油水分离膜提供了新思路。指出了疏水性膜用于油水分离的过程原理及应用现状：含油废水除油中,疏水性膜可实现O/W乳液的破乳、粗粒化油滴、滤除油滴及吸附油分子几方面的功能;含水油液除水中,膜被用来截留水滴,可直接得到净化的油品。最后,指出了其过程规模化应用前尚需解决的重要问题,特别是高度疏水/超亲油分离膜的制备、相关过程研究的深入及其规模化试验等方面需着力加强。     

三元复合驱含油污水油水分离剂的研制

针对三元复合驱含油污水水相粘度大、油珠粒径小和油珠聚并困难的问题，从阴离子型和非离子型药剂的思路出发，研发了促使三元复合驱含油污水兼有油珠聚结和浮选除油功能的油水分离剂Drows-1，根据Drows-1对O／W型三元复合驱采出液具有良好破乳效果的特点，提出了将油水分离剂的加药点设在三元复合驱采出液破乳之前，采用热化学沉降－浮选处理工艺解决三元复合驱含油污水油水分离问题的思路。     

Biodegradable,superhydrophobic walnut wood membrane for the separation of oil/water mixtures

The preparation of environmentally friendly oil/water separation materials remains a great challenge. Freeze-drying of wood after lignin removal yields wood aerogels, which can be used as substrates to prepare fluorine-free environmentally friendly superhydrophobic materials, However, they are more suitable for absorption rather than filtration applications due to their poor strength. A study using cross-sections of pristine wood chips as substrates retains the original strength of wood, but the use of the cross-sectional of wood pieces limits their thickness, strength, and size. In this paper, a degradable fluorine-free superhydrophobic film (max. water contact angle of approximately 164.2°) with self-cleaning and abrasion resistance characteristics was prepared by a one-step method using pristine and activated walnut longitudinal section films as the substrate, with tetraethyl orthosilicate as a precursor and dodecyltriethoxysilane as a modifier. The tensile strength results show that superhydrophobic films with pristine or activated wood substrates maintained the strength of pristine wood and were 2.2 times stronger than the wood aerogel substrate. In addition, after cross-laminating the two samples, the films had the ability to separate oil and water by continuous filtration with high efficiency (98.5%) and flux (approximately 1.3 × 10³ L∙m^‒2∙h^‒1). The method has potential for the large-scale fabrication of degradable superhydrophobic filtration separation membranes.     

Performance evaluation of modified fabricated cotton membrane for oil/water separation and heavy metal ions removal

Preparation of effective membrane with special surface treatment for oil/water separation having promising future and low manufacturing cost. The suggested membrane was fabricated by a simple treatment via increasing the hydrophilicity of the cotton fabric surface. The cotton fabric was impregnated in poly(acrylic acid-co-N-methylol acrylamide), poly(AA-co-NMA), where NMA acts as bonding agent. Sodium hypophosphite (SHP) was added to the modification solution to enhance the bonding between the cotton fabric and the PAA. The modified fabric was thermally dried and cured at different temperatures. It was found that, the presence of 3.5% NMA and addition of 5% SHP to the modification solution then curing at 190°C gave the highest amount of bonded PAA to the cotton fabric. The success of the modification process was confirmed by scanning electron microscope, Fourier transformer infrared and the increase in the contact angle of the cotton fabric after modification. Furthermore, the prepared membrane was evaluated for oil (n-hexane, toluene, and petroleum ether)/water separation and also for heavy metal ions removal (Cd²⁺ and Co²⁺). Neutralization of the produced membrane with ammonium hydroxide resulting in a higher contact angle and consequently higher separation efficiency for oil/water mixtures and higher performance for heavy metal ions removal compared to the unneutralized one.     

Fabrication of a superhydrophilic/underwater superoleophobic stainless steel mesh for oil/water separation with ultrahigh flux

Because of the increasing amount of oily wastewater produced each day, it is important to develop superhydrophilic/underwater superoleophobic oil/water separation membranes with ultrahigh flux and high separation efficiency. In this paper, a superhydrophilic/underwater superoleophobic N-isopropylacrylamide-coated stainless steel mesh was prepared through a simple and convenient graft polymerization approach. The obtained mesh was able to separate oil/water mixtures only by gravity. In addition, the mesh showed high-efficiency separation ability (99.2%) and ultrahigh flux (235239 L∙m^–2∙h^–1). Importantly, due to the complex cross-linked bilayer structure, the prepared mesh exhibited good recycling performance and chemical stability in highly saline, alkaline and acidic environments.     

原油中酸性组分对油/水乳状液的影响研究

原油中的酸性组分是天然表面活性物质,影响油/水乳状液的稳定性,相关研究对采出液破乳有重要参考价值。作者研究了原油中酸性组分对油/水乳状液破乳效果、乳状液粘度、油/水接触角、界面膜强度的影响,结果如下:随w(酸性组分)从2.25%增加到2.65%,85℃时,脱水率由81.2%降低至14%,粘度由212.3mPa·s增加到1 452mPa·s,乳状液的稳定性大幅度增加;随w(酸性组分)增加,油/水接触角减小,界面膜强度增加;虽然间隔都是0.2%,w(酸性组分)为2.25%和2.45%时,油/水接触角、单滴破裂率相差较大,但w(酸性组分)为2.45%和2.65%时相差较小。