有机溶剂纳滤膜的润湿性对渗透和分离性能的影响

有机溶剂纳滤是一种绿色、高效、节能的新型膜分离技术,在回收和处理有机溶剂中具有广泛的应用前景。本文采用浸渍法分别将聚合物聚二甲基硅氧烷（PDMS）、嵌段聚醚酰胺（PEBAX2533）和聚乙烯醇（PVA）与聚砜（PS）超滤基膜复合,制备了3种不同润湿性的聚合物耐溶剂纳滤膜,研究了PDMS/PS、PEBAX/PS和PVA/PS复合膜对甲醇、乙醇、异丙醇、正己烷、正庚烷的渗透性能,考察了3种聚合物膜对伊文思蓝/甲醇溶液的有机溶剂纳滤性能。结果表明,有机溶剂在不同润湿性复合膜的渗透和传递性能与溶剂本身的溶度参数、分子量、黏度和极性等有很密切的相关性,溶剂的分子量、黏度、分子动力学直径越小,在同一极性复合膜中渗透通量越大;对伊文思蓝/甲醇溶液的有机溶剂纳滤分离表明,PDMS/PS和PEBAX/PS复合膜的截留率均可达90%以上,通量分别为 58.0L/(m²·h·MPa)和72.2L/(m²·h·MPa);PVA/PS复合膜的截留率为85.1%左右,通量为57.5L/(m²·h·MPa)。     

有机溶剂纳滤传递模型及最新膜材料研究进展

有机溶剂纳滤（organic solvent nanofiltration, OSN）是一种高效节能、操作简便的新型膜分离技术,在化工、制药、能源和环境等相关领域具有广阔的应用前景,因此受到了膜技术领域内研究者们的重点关注。本文首先简述了有机溶剂纳滤的应用背景,其次从有机溶剂纳滤传递模型与膜材料两个方面,总结归纳了近年来在有机溶剂纳滤领域取得的研究进展。总结了基于无机陶瓷、高分子聚合物、多孔有机聚合物、有机-无机杂化材料以及石墨烯类二维材料等用于制备新型OSN膜的研究进展,并结合传输模型讨论分析了有机溶剂分子在膜内的传输行为及膜的分离性能。最后简述了有机溶剂纳滤技术在化工及相关行业中的应用现状,并指出了这些关键有机溶剂纳滤膜材料在有机溶剂纳滤应用中存在的优势和挑战,提出了基于这些关键材料的特点进行设计和优化OSN膜性能的建议供参考,以期促进有机溶剂纳滤膜的研究和应用。     

CD-MOF二维层状膜制备及混合溶剂精准分离研究

随着膜分离技术的迅速发展,其应用于混合溶剂分离以替代传统高能耗精馏等操作受到了越来越多研究者的关注,但制备具有均匀亚纳米筛分孔的分离膜是其面临的挑战。利用苯甲酸诱导各向同性的环糊精金属有机框架（CD-MOF）三维立方颗粒产生错层结构,再通过液相超声剥离法制得CD-MOF纳米片,以此为构筑单元制备二维层状MOF膜。膜内CD-MOF纳米片含有丰富、连通且均匀的本征亚纳米孔（0.78 nm）,可识别分子间微小的尺寸差异,实现混合溶剂精准分离。如CD-MOF层状膜对溶解在苯中的均三异丙基苯与二异丙基苯混合液（摩尔比为1∶3）的分离因子达到7.4。此外,膜对溶解在甲醇中的甲基橙染料（1.0 nm）截留率达到99.6%,且甲醇通量达84.3 L·m^-2·h^-1·bar^-1。     

CD-MOF二维层状膜制备及混合溶剂精准分离研究

随着膜分离技术的迅速发展,其应用于混合溶剂分离以替代传统高能耗精馏等操作受到了越来越多研究者的关注,但制备具有均匀亚纳米筛分孔的分离膜是其面临的挑战。利用苯甲酸诱导各向同性的环糊精金属有机框架（CD-MOF）三维立方颗粒产生错层结构,再通过液相超声剥离法制得CD-MOF纳米片,以此为构筑单元制备二维层状MOF膜。膜内CD-MOF纳米片含有丰富、连通且均匀的本征亚纳米孔（0.78 nm）,可识别分子间微小的尺寸差异,实现混合溶剂精准分离。如CD-MOF层状膜对溶解在苯中的均三异丙基苯与二异丙基苯混合液（摩尔比为1∶3）的分离因子达到7.4。此外,膜对溶解在甲醇中的甲基橙染料（1.0 nm）截留率达到99.6%,且甲醇通量达84.3 L·m^-2·h^-1·bar^-1。     

有机溶剂纳滤技术在石油化工生产中的应用

有机溶剂纳滤技术是一种新的有机溶剂膜分离技术，具有能耗低、分离效率高、环境污染小的优势。本文对有机溶剂纳滤技术在石油化工生产领域的应用情况进行了总结，为优化石油化工生产中的应用和研究情况，提高石油化工生产效率和经济性提供了依据。     

Zn-BTC/MoS2复合二维膜构筑及有机溶剂纳滤性能研究

尽管最近兴起的二维膜材料相较于传统的聚合物基膜材料呈现出明显提升的分离性能。但是二维膜中分子传质需要经过层层堆积的二维通道,传输路径较长,限制了二维膜渗透通量的进一步提升。提出用一维金属有机框架纳米线来调控二维膜实现通量提升,同时不降低分离能力。该策略的实现是通过Zn-BTC纳米线插层MoS₂层级膜,制备了Zn-BTC/MoS₂复合膜。该复合膜的有机溶剂通量比MoS₂二维膜提高了2~6倍,丙酮渗透通量高达3562 L·m^-2·h^-1·bar^-1。同时该复合膜保持了与MoS₂膜同等优异的筛分能力,对于尺寸大于0.42 nm的染料分子,可以实现100%截留。     

异质结构g-C3N4@AM层状膜构筑及纳滤性能研究

随着化工行业的迅速发展,利用纳滤膜对有机溶剂进行高效分离受到了越来越多的关注,但有机溶剂纳滤膜通量和选择性之间普遍存在 trade-off 效应的限制。以相对疏水的g-C₃N₄纳米片和亲水的直链淀粉（amylose,AM）为构筑单元,利用双针头静电雾化技术制备了异质结构的g-C₃N₄@AM 层状膜。亲水的直链淀粉促进了极性溶剂的溶解,相对疏水的g-C₃N₄纳米片实现了通道对极性溶剂的低阻力扩散;两者协同,极大地增强了膜对极性溶剂的渗透性能,而不降低分离能力。与纯g-C₃N₄层状膜相比,g-C₃N₄@AM 层状膜对极性溶剂的渗透系数提高了1~2倍,对于尺寸大于 1.5 nm 的染料分子可以实现 99% 以上的截留率。在操作稳定性、压力循环和耐酸碱测试后,膜的渗透性能和截留能力基本保持不变,衰减 < 6%,具有较好的操作稳定性。     

高性能纳滤膜的制备及性能研究

本文以磺化聚醚砜（SPES）为涂层材料,以聚砜（PSF）超滤膜为支撑层,采用涂覆法制备SPES/PSF纳滤脱色膜,研究了有机溶剂,无机、有机添加剂等因素对纳滤脱色膜性能的影响,并通过SEM表征纳滤脱色膜的表面和断面形貌。结果表明,SPES/PSF纳滤脱色膜对甲基蓝的截留率可以达到90%以上,硫酸钠的截留率低于20%,水通量可以达到70 L/（m2·h）以上,实现了低分子染料和无机盐高选择性分离。     

MOFs/PEI混合基质膜的制备及CO2分离性能研究

二氧化碳的分离和捕获对可持续发展具有重要意义。聚醚酰亚胺(PEI)具有优异的耐溶剂、耐高温、选择性高等优势，然而CO₂渗透性能低成为限制其进一步发展的关键瓶颈。通过引入2种三维MOFs颗粒[UIO-66和MIL-101(Cr)]及2种二维MOFs纳米片[CuBDC和Zn₂(bim)₄]制备了4种MOFs/PEI混合基质膜(MMMs),对膜的物理化学性质及CO₂分离性能展开深入研究。结果表明MOFs的引入大幅提高了PEI膜的CO₂扩散系数及分离性能，并改善了PEI膜的抗CO₂塑化性能。同时，相比三维MOFs颗粒，二维CuBDC纳米片与PEI表现出更高的相容性，其填料含量为20%时MMMs的CO₂渗透通量相比纯PEI膜提高了3.5倍，其CO₂/CH₄选择性提高了2.2倍。以二维MOFs纳米片为功能性填料制备混合基质膜用于CO₂分离是一种有效的策略。     

二维层状膜在离子传质与分离方面的研究进展

二维层状膜由二维纳米片的层层堆叠而成，由于相邻纳米片之间二维毛细通道展现出的选择性传质特性，受到研究者广泛关注。从对二维层状膜的溶胀现象出发，系统总结了纳米通道尺寸调控策略，并分析了其他尺寸因素对离子传输行为的影响，总结了通道表面电荷以及特异性结合基团与离子传输与分离效率的关系。综述了近几年有关二维层状膜在离子传质与分离方面的研究现状、进展以及存在问题，旨在为高性能离子筛分层状膜的结构设计和应用提供理论参考。     

Preparation of thin film nanocomposite membranes with surface modified MOF for high flux organic solvent nanofiltration

Preparation of defect‐free and optimized thin film nanocomposite (TFN) membranes is an effective way to enhance the process of organic solvent nanofiltration. However, it still remains a great challenge due to poor filler particle dispersibility in organic phase and compatible issue between fillers and polymers. Aiming at these difficulties, UiO‐66‐NH₂ nanoparticles were surface modified with long alkyl chains and used in the preparation of TFN membranes. As a result, defect‐free TFN membranes with ultrathin MOF@polyamide layer were successfully prepared benefited from the improved particle dispersibility in n‐hexane. Significant enhancement was found in methanol permeance after nanoparticle incorporation, without comprising the tetracycline rejection evidently. Especially, the novel TFN membrane prepared with organic phase solution containing 0.15% (w/v) modified UiO‐66‐NH₂ nanoparticles showed a superior methanol permeance of 20 L·m^?2·h^?1·bar^?1 and a tetracycline rejection of about 99%, which is appealing to the application in pharmaceutical industry for example. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1303–1312, 2017     

Polyaniline membranes for nanofiltration of solvent from dewaxed lube oil

Polyaniline nanofiltration membranes were synthesized to examine a potential candidate for application of solvent recovery from lube oil. An integrally skinned polyaniline membrane was cast on a woven polyester fabric and then was chemically crosslinked with glutaraldehyde in order to further increase the membranes resistant in a methyl ethyl ketone and toluene mixture. Subsequently, membrane performance was tested under different operational conditions. The operation pressure was fixed at 35 bar and was held constant for all of the tests. The membrane demonstrated a permeate flux of 10 l/(m² h) and oil rejection of 69%.

Abbreviations: PANi: Polyaniline; PI: polyimide; MEK: methyl ethyl ketone; GA: glutaraldehyde; NMP: N-methyl-2-pyrrolidone; 4MP: 4-methylpiperidine; SEM: Scanning Electron Microscope; OSN: organic solvent nanofiltration; MWCO: molecular weight cut-off.     

耐溶剂纳滤膜的制备与应用研究进展

有机溶剂纳滤(organic solvent nanofiltration,OSN)是近年来快速发展起来的一项新型纳滤膜分离技术,具有广阔的应用前景。耐溶剂纳滤(solvent-resistant NF,SRNF)膜的制备是OSN技术发展的关键,也是目前的研究热点之一。本文侧重阐述了SRNF膜在制备及应用方面的进展,着重介绍了相转化法、界面聚合法、自组装法及有机-无机杂化法等SRNF膜制备方法。相转化法是目前国内外SRNF膜制备研究常用的方法,但该法所制备的膜皮层较厚,通量明显偏小;界面聚合法SRNF膜制备的相关研究目前较少,但由于其皮层非常薄,因此是SRNF膜制备发展的一大趋势;自组装膜有较好的耐溶剂性能;加入无机物可以提高耐有机溶剂性,有机-无机杂化法的膜制备是SRNF膜制备的趋势之一。同时简单介绍了SRNF膜的应用,并对未来SRNF膜研究的方向提出了建议。     

Enhancement of flux and solvent stability of Matrimid® thin‐film composite membranes for organic solvent nanofiltration

The development of high flux and solvent‐stable thin‐film composite (TFC) organic solvent nanofiltration (OSN) membranes was reported. A novel cross‐linked polyimide substrate, consisting of a thin skin layer with minimum solvent transport resistance and a sponge‐like sublayer structure that could withstand membrane compaction under high‐pressure was first fabricated. Then the solvent flux was significantly enhanced without compromising the solute rejection by the coupling effects of (1) the addition of triethylamine/camphorsulfonic acid into the monomer solution, and (2) the combined post‐treatments of glycerol/sodium dodecyl sulphate immersion and dimethyl sulfoxide (DMSO) filtration. Finally, the long‐term stability of the TFC membrane in aprotic solvents such as DMSO was improved by post‐crosslink thermal annealing. The novel TFC OSN membrane developed was found to have superior rejection to tetracycline (MW: 444 g/mol) but was very permeable to alcohols such as methanol (5.12 lm^?2h^?1bar^?1) and aprotic solvents such as dimethylformamide (3.92 lm^?2h^?1bar^?1) and DMSO (3.34 lm^?2h^?1bar^?1). © 2014 American Institute of Chemical Engineers AIChE J, 60: 3623–3633, 2014     

Polyamide composite membranes for enhanced organic solvent nanofiltration performance by metal ions assisted interfacial polymerization method

Herein, thin-film composite membranes consisting of poly(m-phenyleneisophthalamide) substrate and polyamide active layer were constructed by transition metal ion-assisted interfacial polymerization method. As compared to the traditional polyamide membranes, a much thinner polyamide layer (33 vs. 200 nm) can be synthesized with higher permeance (3.2 vs. 0.62 L m⁻² h⁻¹ bar⁻¹) in the organic solvent nanofiltration. Similarly, the prepared membranes maintained a high rejection (>99%) for various dyes. Optimal membranes prepared by using Co²⁺ exhibited strong tolerance to various organic solvents with good long-term stability. Positron annihilation spectroscopy and other characterization methods were used to investigate the relationships between the membrane microstructures and the enhanced separation performance. Based on molecular dynamics simulation, it was found that the diffusion coefficient of polyethyleneimine monomer decreased by about 18 times after adding Co²⁺ to the aqueous solution (forming coordination interaction). This procedure has great potential and sustainability for practical organic solvent nanofiltration applications.     

Analysis and optimization of continuous organic solvent nanofiltration by membrane cascade for pharmaceutical separation

The major part of the production costs of pharmaceuticals can be imputed to the downstream processing, where membrane technologies have to deal with some challenges as separations involving solutes with similar sizes or solvent recovery and recycling. This work contributes to the progress in the design of continuous organic solvent nanofiltration systems for this purpose and includes the configuration of dual membrane cascades, sensitivity analysis of the operation variables, and economic optimization as innovations. Analyzed configurations include multistage cascades up to three stages, and dual membrane cascades up to five stages. The total costs (TC) were chosen as the formulated objective function to minimize in the economic optimization strategy. The treatment of the residual stream leaving the system resulted the main cost of the process (more than 85% for dual cascades), but the solvent recovery units can significantly reduce the TC (64–77% depending on the required solvent quality). © 2014 American Institute of Chemical Engineers AIChE J, 60: 931–948, 2014     

双组分无机电解质溶液的纳滤膜分离性能

纳滤膜是20世纪90年代问世的新型分离膜,具有两个显著特点：一是其截留分子量介于反渗透膜和超滤膜之间,约为2002000;另一是纳滤膜的表面分离层由聚电解质构成,一般带有负电荷,因此对无机电解质有一定的截留率．     

Dual-layer membrane with hierarchical hydrophobicity and transport channels for nonpolar organic solvent nanofiltration

Nonpolar solvent separation is widely used in petroleum, chemical, food industries, but traditional separation methods consume intensive energy. State-of-art organic solvent nanofiltration membranes require complex modifications for nonpolar solvent transport. For the first time, we propose the concurrent modification of the surface, interface and support layer of dual-layer membranes with three additives (perfluorodecylamine, fluoro substituted aromatic amine, silica nanoparticles) in a one-step cocasting process. A delamination-free dual-layer membrane was obtained with a hierarchical hydrophobicity and transport channels. The novel designed structure elevated the pure n-hexane permeance (28.75 L m⁻² hr⁻¹ bar⁻¹) by 3 orders of magnitude with a high lecithin rejection (98.7%). This method of synergistically controlling the hierarchical structures and properties of dual-layer membranes can significantly shorten the preparation process of high-performance nonpolar solvent nanofiltration membranes.