微孔膜法油水分离——表面性质及微观结构的研究进展

石油炼制和化工过程存在大量油水混合物体系,影响生产过程稳定性,也会造成环境污染,亟需高效低成本的油水分离技术。与气浮、离心、化学混凝等传统油水分离技术相比,微孔膜技术通过油或水的选择性渗透实现分离,具有操作简单、分离效率高、运行成本低等众多优点。然而,微孔膜处理油水混合物的分离效率和加工能力同时取决于膜材料的表面性质（表面浸润性能）和微孔结构（分离通道的尺寸效应）。本文首先基于表面润湿现象和尺寸筛分机制介绍了膜法油水分离的原理,然后从上述两个角度出发综述了近年来微孔膜法油水分离的相关研究进展,最后指出微孔膜法油水分离在迈向工业化应用的过程中还需解决的一些问题,并对未来膜材料表面性质和微孔结构的研究进行了展望。     

面向油水分离的无机膜制备及应用进展

膜技术是处理含油污水及含水油液的有效分离方法。无机膜材料由于可调变的表面性质和良好的稳定性,即使在苛刻的条件下,在分离油水方面表现出优异的分离性能。本文首先阐述了设计与制备油水分离膜的理论基础,包括分离过程中压力驱动力和膜表面特性对膜通量和选择性的影响;然后综述了当前国内外用于油水分离的无机膜的制备及其应用进展,重点介绍分子筛膜、金属氧化物/金属氢氧化物膜和氧化石墨烯膜等的研究,分析了在不同油水混合物中研究者们调控无机膜表面性能的策略,提出膜表面润湿性和膜结构是提高膜分离效率和抗污染性的关键;最后指出抵制含大量表面活性剂、碱液及有机聚合物种的乳化油对膜造成污染,是无机膜亟需解决的问题,并展望了无机膜在分离油水方面的发展方向。     

室温下ZnO超疏水表面的制备及油水分离性能

利用简便的液相法,在室温下于不锈钢网上沉积ZnO纳米片和纳米花粗糙结构,接着通过浸渍法修饰低表面能物质硬脂酸,制备了超疏水不锈钢网。对沉积后的不锈钢网表面形貌、晶体结构、润湿性能、耐磨性能、油水分离性能等进行表征与测定。结果表明,该不锈钢网表面由纳米片和纳米花组成的微纳米结构ZnO构成,具有超疏水性,水接触角161 °;油水分离效率达98%,循环使用20次后分离效率仍保持在95.5%以上;具有良好的机械耐磨性,在高盐环境中表现出化学稳定性。     

油水重力分离设备技术及进展

结合作者工作实践,从油水分离技术工业设备应用的现状和生力分离设备的发展概况等方面,介绍了油水重力分离设备的发展过程。     

特殊润湿性表面的油水分离研究进展

以油水分离的材料表面润湿性为主线,介绍了特殊润湿性表面的制备机理,分析了超疏水超亲油、超亲水超亲油、超亲水超疏油、可转换润湿性的智能表面的优缺点,提出了特殊润湿性材料在油水分离方面的改进方向。未来特殊润湿性材料表面必定向环保、低廉、多功能的方向发展。     

特殊润湿性表面的油水分离研究进展

以油水分离的材料表面润湿性为主线,介绍了特殊润湿性表面的制备机理,分析了超疏水超亲油、超亲水超亲油、超亲水超疏油、可转换润湿性的智能表面的优缺点,提出了特殊润湿性材料在油水分离方面的改进方向.未来特殊润湿性材料表面必定向环保、低廉、多功能的方向发展.     

膜淤塞对微滤的油水分离性能的影响

本文报道了用微滤分离乳化含油废水的研究，利用微滤过程中膜淤塞的特点，显著地提高了油水的分离效率，同时维持较高的水透过率。文章讨论了油水分离的机理，并根据实验结果提出流体中适当的油粒粒径分布，是获得较好分离效果的重要条件。本研究表明了在一定下，可以用水透过率较高、操作成本降低的微滤取代超滤。     

特殊浸润性膜的油水分离研究进展

以特殊浸润材料的浸润机理出发,介绍了构建具有特殊浸润性膜的方法,阐述了"去油型"、"去水型"、"智能控制型"分离膜的研究成果。具有特殊浸润性的膜分离效率高、循环性能好,在处理油水混合物方面有极大的潜力。对其现存的问题及未来发展进行了展望,认为需要开发出分离性能好、抗污染性能优异、可大规模生产的商业膜;需要解决分离后乳化剂的去除问题,以及在分离过程中对膜污染的清洗方式、清洗效果;迫切需要开发出一种可同时分离"油包水""水包油"混合物的高效简单分离膜。     

聚乳酸电纺纤维膜的油水分离性能

采用静电纺丝法,制备了聚乳酸(PLA)电纺纤维膜。通过扫描电子显微镜、接触角测试仪等表征了PLA电纺纤维膜的纤维结构和水接触角,并研究了其油水分离性能。结果表明PLA可纺性好,电纺纤维膜为由光滑的微纤维组成的三维多孔网络结构,纤维直径1～2μm,纤维膜孔径为3～10μm且分布较均匀。PLA电纺纤维膜的水接触角可达136°以上,具有良好的疏水性。PLA电纺纤维膜对油水混合物的分离效率可达98.3%以上,最大分离通量约15 000 L·m^-2·h^-1。     

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。     

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.     

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。     

Preparation of three-dimensionally linked pore-like porous atomized ceramics with high oil and water absorption rates

Ceramic atomization cores are a new application of porous ceramics; however, the challenging regulation of the pore structures of porous ceramics has limited their application. To improve the low liquid absorption rates and low liquid storage capacity of porous ceramics in the field of atomization, this study used three substances, polymethyl methacrylate (PMMA), starch, and diatomaceous earth, to produce porous ceramics with a three-dimensional interconnected triple-porous structure by sacrificial templating. In the porous ceramics, large pores resulting from PMMA increase liquid storing capacity, medium pores resulting from the starch facilitate the transport of liquid, and small pores resulting from diatomaceous earth enhance capillary action, significantly increasing the rate of liquid absorption. By varying the PMMA contents and type of starch in the preform, water and oil storage capacities of up to 123% and 143%, respectively, can be achieved. We found that an optimized porous ceramic with dimensions of 15 mm × 15 mm × 15 mm absorbs water rapidly (reaching saturation in only 1.67 s), demonstrates good solid–liquid properties and shape stability, and is recyclable (requires drying before reuse). The proposed porous ceramics have promising atomization core and oil–water separation applications.     

Extracting hydrocarbons from Huadian oil shale by sub-critical water

The possibility of extracting hydrocarbons from Huadian oil shale by sub-critical water was found in a stainless steel vessel. The effects of temperature and pressure on the extraction of hydrocarbons were studied. After extraction experiments, the residual solid, liquid and gas phase samples were collected and characterized, respectively. The extract yield could reach 7 wt.% (ad) when the extraction of oil shale was conducted at 260 °C for 2.5 h with the pressure of 15 MPa. The results of thermogravimetry (TG) showed that the weight loss of residual solid samples was much smaller than that of the original oil shale. It indicated that kerogen components had been decomposed partly by treatment with sub-critical water. Gas chromatography-mass spectrometry (GC-MS) analysis showed that there were more than 300 recognizable peaks in the extracting solution following processing at 330 °C and 18 MPa. Large amounts of high molecular weight hydrocarbons were gradually decompounded by the increase in types and levels of low molecular weight hydrocarbons, and polycyclic and heterocyclic compounds with the rising of pressure and temperature. These indicated that sub-critical water is capable of cracking kerogen into smaller hydrocarbon compounds at relatively low temperatures.     

油水分离技术在钢厂浊循环水处理改造中的应用

循环冷却水水质状况直接影响到钢厂浊循环水的应用,如何有效去除循环水中的油类和氧化铁皮是整个处理过程的技术关键.作者通过对某钢厂浊循环水处理工程的技术改造设计及运行实际效果的分析,阐述了油水分离技术的过程与原理、设计参数,以及该项技术在浊循环水处理中的应用及效果.     

Removal of oil from oil/water emulsions using electroflotation process

Dispersed oil was separated from oil–water emulsions in an electroflotation cell equipped with insoluble electrodes: titanium coated with ruthenium oxide as anode and stainless steel screen as cathode. The effect of operating parameters such as current density, oil concentration, flotation time and coagulant concentration, on the performance of the electroflotation cell was examined. Oil removal reached 70% at optimum conditions; 75% in the presence of NaCl (3.5% by wt); and 99.5% in the presence of both NaCl and an optimum concentration of coagulant. Electrical energy consumption varied from 0.4 to 1.6 kWh m⁻³ according to experimental conditions. The performance of the oil removal process was also represented by a first order kinetic rate model. The constants obtained fit the experimental data well. Good correlation was found for the change in percentage oil removal within a wide range of operating parameters.     

对油水乳浊液分离的研究

本文主要研究了操作条件的改变对分离效果的影响，在研究中还考察了NaCl和絮凝剂加入乳浊液后对分离过程产生的增效作用。得到了一个与实验数据相关联的数学方程，为估算油的去除率提供了一个有用的工具。在电浮选装置中采用不溶电极，为今后的分离技术提供了一个新思路。     

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.     

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.