Tungsten incorporated mobil-type eleven zeolite membranes: Facile synthesis and tuneable wettability for highly efficient separation of oil/water mixtures

Tungsten (W) incorporated mobil-type eleven (MEL) zeolite membrane (referred to as W-MEL membrane) with high separation performance was firstly explored for the separation of oil/water mixtures under the influence of gravity.W-MEL membranes were grown on stainless steel (SS) meshes through in-situ hydrothermal growth method facilitated with (3-aminopropyl)triethoxysilane (APTES) modification of stainless steel meshes,which promote the heterogeneous nucleation and crystal growth of W-MEL zeolites onto the mesh surface.W-MEL membranes were grown on different mesh size supports to investigate the effect of mesh size on the separation performance of the membrane.The assynthesized W-MEL membrane supported on 500 mesh (25μm)(W-MEL-500) exhibit the hydrophilic nature with a water contact angle of 11.8°and delivers the best hexane/water mixture separation with a water flux and separation efficiency of 46247 L·m^(-2)·h^(-1)and 99.5%,respectively.The wettability of W-MEL membranes was manipulated from hydrophilic to hydrophobic nature by chemically modifying with the fluorine-free compounds (hexadecyltrimethoxysilane (HDTMS) and dodecyltrimethoxysilane(DDTMS)) to achieve efficient oil-permselective separation of heavy oils from water.Among the hydrophobically modified W-MEL membranes,W-MEL-500-HDTMS having a water contact angle of146.4°delivers the best separation performance for dichloromethane/water mixtures with a constant oil flux and separation efficiency of 61490 L·m^(-2)·h^(-1)and 99.2%,respectively along with the stability tested up to 20 cycles.Both W-MEL-500-HDTMS and W-MEL-500-DDTMS membranes also exhibit similar separation performances for the separation of heavy oil from sea water along with a 20-fold lower corrosion rate in comparison with the bare stainless-steel mesh,indicating their excellent stability in seawater.Compared to the reported zeolite membranes for oil/water separation,the as-synthesized and hydrophobically modified W-MEL membranes shows competitive separation performances in terms of flux and separation efficiency,demonstrating the good potentiality for oil/water separation.

Fouling-resistant Composite Membranes for Separation of Oil-in-water Microemulsions

Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water (O/W) microemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a porous ceramic membrane substrate, a polyvinylidene fluoride (PVDF) ultrafiltration sub-layer, and a polyam-ide/polyvinyl alcohol (PVA) composite thin top-layer. The PVDF polymer was cast onto the tubular porous ceramic membranes with an immersion precipitation method, and the polyamide/PVA composite thin top-layer was fabricated with an interfacial polymerization method. The effects of the sub-layer composition and the recipe in the interfacial po-lymerization for fabricating the top-layer on the structure and performance of composite membranes were systematically investigated. The prepared composite membranes showed a good performance for treating the O/W microemulsions with a mean diameter of about 2.4μm. At the operating pressure of 0.4MPa, the hydraulic permeability remained steadily about 190L?m-2?h-1, the oil concentration in the permeate was less than 1.6mg·L-1, and the oil rejection coefficient was always higher than 98.5% throughout the operation from the beginning.

Electrospinning organic solvent resistant preoxidized poly(acrylonitrile)nanofiber membrane and its properties

A high performance preoxidized poly(acrylonitrile)(O-PAN)nanofiber membrane with excellent solvent resistance,thermal stability and flexibility was fabricated by the preoxidation of electrospun PAN nanofiber membrane.The performance of resultant O-PAN nanofiber membrane was optimized by altering the PAN concentration and preoxidation temperature.The results showed that the O-PAN nanofiber membrane which made from PAN concentration of 14%(mass)and preoxidation temperature of 250.0
℃ have a more optimal comprehensive performance.In the long-term separation test of SiO2 particle(1 μm)in DMAc suspension,the permeate flux of O-PAN nanofiber membrane stabilized at 227.91 L·m^(-2)·h^(-1)(25
℃,0.05 MPa)while the SiO2 rejection above 99.6%,which showed excellent solvent resistance and separation performance.In order to further explore the application of the O-PAN nanofiber membrane,the OPAN nanofiber membrane was treated with fluoride and used in oil/water separation process.The O-PAN nanofiber membrane after hydrophobic treatment showed excellent hydrophobicity and good oil/water separation performance with the permeate flux about 969.59 L·m^(-2)·h^(-1)while the separation efficiency above 96.1%.The O-PAN nanofiber membrane exhibited a potential application prospect in harsh environment separation.

Produced Water from Oil and Gas Exploration—Problems, Solutions and Opportunities

Large volumes of water are generated in gas- and oil-production. This includes the water that is present originally in the reservoirs, but also water that is injected into the wells. While currently much of the produced water is either reinjected or disposed of after treatment, treated produced water is increasingly seen as an interesting resource, especially in water-scarce regions. This review looks at different PW treatment methods available, with an emphasis on the management of PW in oil- and gas production on the Arabian Peninsula.

Flexible,durable,and anti-fouling nanocellulose-based membrane functionalized by block copolymer with ultra-high flux and efficiency for oil-in-water emulsions separation

The clearwater obtained from stabilized oily wastewater has become a worldwide challenge.Nowdays,the area of oil/water emulsion separation materials have accomplished great progress,but still faces the enormous problems of low flux,poor stability,and pollution resistance.Nanocelluloses(cellulose nanocrystals(CNC))with the advantages of hydrophilicity,ecofriendliness,and regeneration are ideal materials for the construction of separation membranes.In this paper,a flexible,antifouling,and durable nanocellulose-based membrane functionalized by block copolymer(poly(N-isopropylacrylamide)-b-poly(N,Ndimethylaminoethyl methacrylate))is prepared via chemical modification and self-assembly,showing high separation efficiency(above 99.6%)for stabilized oil-in-water emulsions,excellent anti-fouling and cycling stability,high-temperature resistance,and acid and alkali resistance.More importantly,the composite membrane has ultra-high flux in separating oil-in-water emulsions(29,003 L·m^(−2)·h^(−1)·bar^(−1))and oil/water mixture(51,444 L·m^(−2)·h^(−1)·bar^(−1)),which ensures high separation efficiency.With its durability,easy scale-up,and green regeneration,we envision this biomass-derived membrane will be an alternative to the existing commercial filter membrane in environmental remediation.

Green Fabrication of Underwater Superoleophobic Biopolymeric Nanofibrous Membranes for Effective Oil-Water Separation

Currently,most of the materials for oil-water separation membranes are limited to fluorine-based polymers with low surface energy.However,it is not biodegradable and requires large amounts of organic and toxic solvents in the membrane manufacturing process.Therefore,interest in the development of a new eco-friendly oil-water separation membrane that does not cause secondary pollution and exhibits selective wettability characteristics in water or oil is increasing.The biopolymeric nanofibrous membranes inspired by fish skin can provide specific underwater oleophobicity,which is effective for excellent oil-water separation efficiency and prevention of secondary contamination.Fish gelatin,which is highly soluble in water and has a low gelation temperature,can be electrospun in an aqueous solution and has the same polar functional groups as the hydrophilic mucilage of fish skin.In addition,the micro/nanostructure of fish skin,which induces superoleophobicity in water,introduces a bead-on-string structure using the Rayleigh instability of electrospinning.The solubility of fish gelatin in water was removed using an eco-friendly crosslinking method using reducing sugars.Fish skin-mimicking materials successfully separated suspended oil and emulsified oil,with a maximum flux of 2086 Lm^(−2) h^(−1) and a separation efficiency of more than 99%.The proposed biopolymeric nanofibrous membranes use fish gelatin,which can be extracted from fish waste and has excellent biodegradability with excellent oil-water separation performance.In addition,polymer material processing,including membrane manufacturing and crosslinking,can be realized through eco-friendly processes.Therefore,fish skin-inspired biopolymeric membrane is expected to be a promising candidate for a sustainable and effective oil-water separation membrane in the future.

特殊润湿性膜在油水分离中的应用进展

石油泄漏和含油废水排放严重污染生态环境,油水分离技术是涉油污染治理的重要手段。由于低耗能、简单高效等优点,特殊润湿性的膜材料在油水分离方面表现出巨大的应用潜力。基于润湿性相关理论和分离机理,总结了超疏水/超亲油膜、超亲水/水下超疏油膜、Janus膜和智能响应膜等油水分离膜的研究进展,并对油水分离膜的优缺点进行了分析,对将来的发展提出了展望。

Rapid formation of metal-monophenolic networks on polymer membranes for oil/water separation and dye adsorption

Surface deposition based on metal-phenolic networks(MPNs) has received increasing interest in recent years. The catechol structure is generally considered to be essential to the formation of MPNs. Our most recent results have demonstrated that some kinds of monophenols can form MPNs on substrate surfaces.Herein, we report a fast and effective surface-coating system based on the coordination of 3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid, a kind of monophenol, with Fe^(3+). Compared with other metal ions such as Cu^(2+)and Ni^(2+), Fe^(3+)with stronger electron acceptability can coordinate with the monophenol more strongly to form MPNs, and moreover, the deposition time significantly decreases to 40 min from generally 24 h. It is demonstrated that the deposition process is controlled by the coordination, Fe^(3+)hydrolysis, and deprotonation of the monophenol. The coatings endow substrates such as polypropylene microfiltration membrane with underwater superoleophobicity, which can be applied in oil/water separation with high separation efficiency and great long-term stability. In addition, the coated membranes are positively charged and thus are useful in selective adsorption of dyes. The present work not only provides a novel, fast, and one-step deposition method to fabricate MPNs, but also demonstrates that the fabrication efficiency of monophenol-based MPNs is comparable with that of polyphenol-based MPNs.

g-C_(3)N_(4)/MXene@Ag多功能膜制备及其水净化性能研究

通过真空辅助组装构建g-C_(3)N_(4)/MXene@Ag(CNMA)分离膜。研究表明,银纳米粒子的引入可以增强表面润湿性并优化传质通道,复合膜最高分离通量(对水包1,2-二氯乙烷乳液)为(6812.7±106)L m^(-2)h^(-1)bar^(-1),最大效率可达99.7%。值得注意的是,CNMA复合膜具有显著的抗污能力,在连续使用10次后仍保持稳定的分离性能。此外,MXene@Ag材料能够优化复合膜体系的能带结构,促进电子-空穴(e^(-)-h^(+))的有效空间分离,从而改善光电性能,实现对有机污染物(染料、抗生素)的高效去除,其中对亚甲基蓝染料的降解效率为98%。CNMA分离膜适用于有机污染物场景下的水环境修复,满足实际污水处理要求,具有十足的发展前景。

多孔通道结构纳米纤维膜的制备及油水分离性能

通过静电纺丝制备以聚丙烯腈(polyacrylonitrile,PAN)/聚乙烯吡咯烷酮(polyvinylpyrrolidone,PVP)为壳,PVP/纤维素纳米晶体(cellulose nanocrystal,CNC)为核的Janus结构纳米纤维膜,并利用绿色的水刻蚀法获得用于油水分离的多孔通道结构纳米纤维膜。结果表明,多孔通道结构增加了纳米纤维内部的储水空间,提供了额外的水分渗透路径,赋予了纳米纤维膜优异的亲水性和水下超疏油性。纳米纤维膜的孔隙率从54%提升至83%,水下油接触角从134°提升至164°,水通量从731 L/(m^(2)·h)提升至3344 L/(m^(2)·h)。纳米纤维膜对水包正己烷乳液的渗透通量高达1985 L/(m^(2)·h),滤液中的TOC含量低于50 mg/L,表明其油水分离效果较好。这种多孔通道结构纳米纤维膜的设计理念为开发油水分离膜提供了一种绿色的制造思路。

聚醚胺D230对聚偏氟乙烯膜表面亲水改性及其油水分离性能

针对聚偏氟乙烯(PVDF)油水分离膜普遍存在分离效果差、易受油污染等问题,受破乳剂多支链聚醚的化学结构和水下超疏油生物表面启发,将具有聚氧丙烯链段的聚醚胺D230引入到PVDF膜表面,构建聚醚胺功能化聚偏氟乙烯(PVDF)超滤膜。首先将PVDF与聚苯乙烯马来酸酐(SMA)共混,采用非溶剂致相转化法制备表面富含酸酐基团的SMA/PVDF膜,然后将膜浸泡于聚醚胺D230溶液中,聚醚胺的端胺基与膜表面的酸酐基团进行表面原位接枝,从而将亲水性聚醚链段固载于膜表面,改善膜表面润湿性和抗污染性。探究聚醚胺D230对膜表面的亲水改性效果及改性膜对含油污水的分离性能。结果表明:随着反应时间延长,膜表面D230的接枝率上升,在最优反应时间9 h下,达到接枝率387.8 mg/g;SMA/PVDF膜表面接枝D230后,膜表面的亲水性显著增强,纯水接触角降低至48.5°,水通量从接枝前的30 L/(m^(2)·h)提高至87 L/(m^(2)·h);D230接枝SMA/PVDF膜表现出水下超疏油特性,其对煤油的水下油接触角达到152°,且对油无黏附性,表现出良好的抗油污性能;D230接枝SMA/PVDF膜对十二烷基硫酸钠(SDS)稳定的煤油/水乳状液具有分离效果,截油率达到99.0%,远高于SMA/PVDF对照膜的60.8%,在油水分离领域具有潜在应用价值。

3D打印聚乳酸膜及其油-水分离性能

采用3D(3-Dimension)打印技术制备了具有规则孔道结构且孔径可控的多孔聚乳酸(PLA)膜,然后以聚乙烯醇(PVA)为表面改性剂,利用氢键交联作用制备了PVA/PLA复合膜。当PLA膜基底填充率为70%时制备的PVA/PLA-70%复合膜的水下油接触角为165.9°,具有超疏油特性。在使用微量水润湿油-水分离膜条件下,PVA/PLA-70%复合膜的油-水分离实验结果表明:PVA/PLA-70%复合膜的油-水分离效率大于99%、水通量高达73.12 L/(m^(2)·s);油-水分离循环使用80次后,分离效率仍大于97%,且水通量稳定在56.10 L/(m^(2)·s),PVA改性PLA膜具有良好的循环稳定性。利用3D打印技术为制备可生物降解的油-水分离膜提供了新的研究方法。

纤维素膜在船舶排油污水分离系统中的应用

船舶在运输中会排放很多含油污水,对含油污水的处理具有重要的意义。纤维素膜具有多孔结构、亲水性和疏水性的特点,是一种较为常见的油水分离方法,本文提出一种基于纤维素膜技术的船舶排油污水分离系统,分析纤维素膜油水分离的原理和常见的改性方法,研究一种改性羧甲基化纤维素膜的制备方法,并对制备的改性纤维素膜性能进行分析。本文提出的船舶排油污水分离系统具有较好的油水分离效率和较高的膜通量,具有一定的应用价值。

部分碳化PTFE/PVDF中空纤维膜的制备及油水分离性能研究

聚四氟乙烯(PTFE)是一种强疏水的氟碳材料,很难用相转化成膜。本文将PTFE粉体分散在聚偏氟乙烯(PVDF)溶液中得到PTFE悬浮液,首先用干湿相转化法制得PTFE/PVDF中空纤维膜胚;然后在氮气气氛下进行部分碳化,制得部分碳化PTFE/PVDF中空纤维膜.用热重分析法、X射线光电子能谱(XPS)和扫描电镜研究了PTFE/PVDF中空纤维膜胚的碳化工艺、膜碳化前后表面元素和微观结构变化情况;最后测试了膜的亲疏水变化和油水分离性能.结果表明:PTFE/PVDF中空纤维膜胚中的PVDF在360~450℃时发生C-H断裂,PTFE保持原结构,可以得到部分碳化PTFE/PVDF中空纤维膜.经部分碳化工艺制得的中空纤维膜孔径减小,形成连续、完整的微孔结构.当PTFE含量为40%时,碳化后制得的膜接触角达到102°,疏水性提高;对10%的模拟含油废水的渗透通量达到30 L/(m^(2)·h)(跨膜压差:0.1 MPa)、分离效率达到80%,呈现出较好的油水分离性能和商业应用价值.

多巴胺改性废弃口罩制备超亲水油水分离膜

始于2019年底的新型冠状病毒(COVID-19)的传播,使得废弃口罩的处置成为人类面临的新挑战。通过在废弃口罩表面原位沉积SiO2纳米颗粒,进而接枝多巴胺(DA),制备得到性能优良的超亲水油水分离膜,改性后膜的水接触角为0°,重力作用下通量达到6953 L·m^(-2)·h^(-1),油水分离效率超过98.65%,且在不同酸碱度(pH=2~14)均表现出稳定的油水分离性能。废弃口罩改性制备油水分离膜为废弃口罩的处置及资源化利用提供了一种新思路,具有很好的社会经济效益。

疏水SiO_(2)纤维膜的制备及其油水分离性能

探讨疏水SiO_(2)纤维膜的制备及其油水分离性能。以硅酸四乙酯和甲基三甲氧基硅烷为原料,采用静电纺丝技术制备疏水SiO_(2)纤维膜并测试其油水分离性能。结果表明:SiO_(2)纤维膜的水接触角为126°,疏水性良好,可以仅在重力作用下有效地分离不同种类的油水混合物。对于重油‐水和轻油‐水混合物的分离通量均高于16 225 L/(m^(2)·h),分离效率大于97.9%。经过10次循环后通量损失均低于3.73%,循环稳定性好。认为:疏水SiO_(2)纤维膜在环境保护方面,特别是在含油废水的处理方面具有潜在应用。

不同孔径陶瓷膜硅烷改性及油水分离性能研究

具有低表面能的疏水陶瓷膜常用于含水油液分离,而渗透通量的提高是提升膜分离过程经济性的关键.本文通过有机硅烷接枝改性制备疏水陶瓷膜,研究硅烷改性对不同孔径陶瓷膜结构及油水分离性能的影响。以孔径为1 000 nm、100 nm、10 nm的3种陶瓷膜为研究对象,考察不同孔径陶瓷膜硅烷化改性前后膜表面微观形貌、润湿性及渗透阻力的变化,评价3种孔径疏水陶瓷膜在溶剂、酸碱等环境下的稳定性,并将3种孔径硅烷改性的陶瓷膜用于油包水乳液分离.结果表明,孔径越小的膜硅烷化改性后渗透阻力增幅越大,尤其是当孔径达到10 nm,改性前后渗透阻力相差近3倍;原膜孔径对改性膜润湿性影响不大,且均表现出良好的耐溶剂性、耐酸碱性.低压高流速的操作方式有利于提高改性膜通量;对于水含量1 000μL/L的W/O乳液,3种改性膜对水的截留率均超过93%,渗透液水含量低于70μL/L,其中1 000 nm改性膜通量最高,达375 L/(m^(2)·h),而10 nm膜更不易被污染;对于水含量10%(体积分数)的W/O乳液,1 000 nm改性膜污染非常严重,通量迅速下降为14.1 L/(m^(2)·h),而100 nm改性膜污染程度较小,通量较高.

基于强氢键作用的超分子微纳米涂层改性滤膜

为解决油水分离滤膜循环使用性差的问题,采用超分子鞣酸-聚乙烯醇(TA-PVA)黏结剂黏附鞣酸-铜(TA-CuⅡ)形成鞣酸-聚乙烯醇-铜(TA-PVA-CuⅡ)涂层改性聚偏氟乙烯(PVDF)膜,制备了具有稳定微纳米涂层的超亲水/水下超疏油膜(TA-PVA-CuⅡ@PVDF)。采用SEM、FTIR、XPS对制备的膜进行了表征,对改性前后PVDF膜的表面润湿性、油水分离性进行了测试,考察了二价铜离子改性时间对TA-PVA-CuⅡ@PVDF循环使用性以及涂层耐久性的影响。结果表明,在亲水性TA-PVA-CuⅡ微纳米涂层的作用下,TA-PVA-CuⅡ@PVDF的水接触角和水下油接触角分别可达到0°和151.0°,其对乳化油的分离膜通量和分离效率最高分别可达1169.30 L/(m^(2)·h)和99.99%,展现出优异的油水分离性能。二价铜离子改性时间为20 min时,TA-PVA-CuⅡ@PVDF循环稳定性和耐久性最佳,具有15次的循环分离次数,并且通量改变率为6.6%。

绿色纤维素基水凝胶膜的制备及油水分离性能

以杨木粉(PF)中提取的纤维素木浆(PF-NA)为基底,通过冷冻盐析技术,利用聚乙烯醇(PVA)将LiCl颗粒包裹在纤维素骨架上制备了纤维素基(CLH)水凝胶膜。采用FTIR、SEM、XRD、XPS对CLH水凝胶膜进行了表征,对其机械、高温、耐酸碱和耐盐稳定性、自清洁和耐污性进行了测试。结果表明,CLH水凝胶膜具有三维层状结构,PVA的加入及冷冻盐析技术的利用提高了CLH水凝胶膜的力学性能。LiCl作为吸水单元分布在纤维素骨架周围,使CLH水凝胶膜具有超亲水性,水下油接触角为151°;在重力作用下,CLH水凝胶膜可以实现对油水混合物和水包油乳液的高效分离,在高温(60℃)、强酸(pH=3)和强碱(pH=13)条件下具有稳定的分离效率(≥99.8%);在循环分离12次水包机油乳液中,CLH水凝胶膜保持稳定的分离性能;CLH水凝胶膜对四氯乙烯油渍具有自清洁和耐污能力。

NDM/Cu(OH)2油水分离膜的制备及分离效果分析

为提高Cu(OH)2泡沫铜的油水分离能力,将泡沫铜浸入正十二烷基硫醇(NDM)制得NDM/Cu(OH)2油水分离膜,经过NDM修饰后的泡沫铜实现了连续高效捕获微米级油滴的目的。研究结果表明:油水分离膜具有大约150μm孔径的Cu(OH)2孔状结构;相比未修饰油水分离膜,NDM修饰的油水分离膜的分离效果明显增加,均达95%以上。该研究有助于提高油水分离效果,为后续的应用测试奠定一定的理论基础。