荷正电季铵化壳聚糖/聚醚酰亚胺复合纳滤膜的制备及性能研究

以无纺布增强具有耐溶剂、耐热特性的聚醚酰亚胺(PEI)超滤(UF)膜为支撑层,具有荷正电性和良好成膜性的2-羟丙基三甲基氯化铵壳聚糖(HACC)为功能层,制备了一种荷正电HACC/PEI复合纳滤(NF)膜。考察了聚合物浓度、反应时间、交联剂浓度及交联温度等对所制备的复合纳滤膜性能的影响,并利用扫描电镜(SEM)观察了该复合纳滤膜的表面形貌。结果表明:最佳制备条件下得到的HACC/PEI复合纳滤膜在0.3 MPa、20℃下对MgCl2具有较好的分离效果,其通量和截留率分别为10.9 L/(m2·h)和83.1%;另外,HACC/PEI复合纳滤膜呈现典型的荷正电特征,对二价无机盐具有较高的截留率。     

耐溶剂纳滤膜研究进展

纳滤的诸多优点使其在有机溶剂体系中具有极大的潜在应用价值,耐溶剂纳滤膜(SRNF)的制备是有机溶剂纳滤发展的关键。本文从耐溶剂纳滤膜材料出发,综述了耐溶剂纳滤膜的制备及应用等方面的研究进展。重点介绍了均相膜、复合膜等多种耐溶剂纳滤膜材料及制备方法,并对今后研究的发展方向提出建议。     

胺基化氧化石墨烯复合纳滤膜对染料的截留性能研究

采用N,N-二甲基乙二胺对Hummers法制备的氧化石墨烯(GO)进行荷正电改性,得到胺基化氧化石墨烯(AGO);然后以聚砜超滤膜为基膜,采用压力驱动自组装法分别制备GO和AGO复合纳滤膜,选择阳离子染料亚甲基蓝和阴离子染料甲基橙作为模型染料,考察改性前后GO纳滤膜的纯水渗透通量及其对不同荷电性染料的脱除效果。结果表明,改性后AGO纳滤膜的纯水渗透通量明显高于GO纳滤膜,且相同压力、相同浓度下AGO纳滤膜对亚甲基蓝的脱除率明显高于GO纳滤膜,而对甲基橙的脱除效果与之截然相反,证明N,N-二甲基乙二胺对增强GO表面荷正电性改性成功。     

耐污染性复合纳滤膜制备技术研究进展

商业化纳滤膜绝大多数采用由二元胺与多元酰氯在非织造布基超滤膜表面界面聚合得到的复合纳滤膜。复合纳滤膜以其基膜和功能层材料可以分别设计,能够在较低压力下同时获得高脱盐率和水通量的优点,而被广泛应用在膜法水处理领域中。然而由于因环境中无机盐结垢、胶体、有机物和生物膜引起的膜污染,造成产水水质及膜通量的下降,膜寿命大大降低且运行成本增加,迫切需要提高复合纳滤膜的耐污染性。本文从新型单体开发、功能层及新型基膜这三大方面探讨目前复合纳滤膜耐污染性的研究进展,并对其制备方法中亟需深入研究的内容和其应用前景进行了展望。     

热处理对聚哌嗪酰胺复合纳滤膜性能的影响

针对聚哌嗪酰胺复合纳滤膜的制备过程热处理中存在的可能影响界面聚合程度的因素,采用自制的烘箱对复合纳滤膜进行热处理,并研究膜性能的变化规律。烘箱以变频鼓风机控制空气体积流量为200~1 200 m~3/h。考察了热处理温度、鼓风流量对复合纳滤膜性能的影响,研究了所得纳滤膜的氯化钠与硫酸镁截留率、水通量。对不同鼓风速率所制备的纳滤膜表面进行了扫描电子显微镜与全反射傅里叶红外光谱分析。结果表明,烘箱的鼓风流量和温度共同决定了界面聚合过程,从而最终决定了纳滤膜的水处理性能。     

新型复合纳滤膜研究进展

纳滤膜因操作压力低、通量高、具有分离选择性以及运行成本较低等优势引起越来越多的关注,目前已在苦咸水脱盐、污水治理和海水淡化等领域发挥着重要作用。界面聚合作为常见的制备聚酰胺纳滤膜的方法,其聚合反应进程的调控可以有效地调节纳滤膜的微观结构,进而对其分离性能产生重要影响。本文从复合纳滤膜的结构入手,总结了当前常用的提升纳滤膜性能的改性方法,包括优化分离选择层、构建中间层、调整底膜结构三个方面,讨论了界面聚合过程反应单体、添加剂种类、制备条件等对分离层结构和分离性能的影响,并分析了底膜的孔径、孔隙率、亲疏水性等理化性质对复合膜性能的影响以及不同类型中间层的优缺点。在此基础上,总结了当前业界内亟待解决的问题,并对纳滤膜的未来发展趋势进行了展望。     

氧化石墨烯改性复合纳滤膜的研究进展

氧化石墨烯(GO)掺杂到膜表面制备的GO-复合纳滤膜具有抗污染能力强、污染物截留率高的特点,是目前研究解决复合纳滤膜污染问题的热点。本文综述了GO-复合纳滤膜的材料选择和主要制备方法,并讨论了GO对GO-复合纳滤膜抗污染性能的影响,为进一步提高GO-复合纳滤膜抗污染性能的研究提供了理论依据和建议。     

基于单宁酸-壳聚糖复合胶体粒子的复合纳滤膜及其脱盐性能

以聚丙烯腈(PAN)超滤膜作为载体,以单宁酸(TA)-壳聚糖(CS)复合胶体粒子作为水相溶液,均苯三甲酰氯(TMC)的正已烷溶液作为有机相单体,通过界面聚合法成功制备了一种高通量、高截留的复合纳滤膜。对纳滤膜的表面形貌及性能进行分析,研究单体质量分数及界面聚合时间对纳滤膜性能的影响,用4种无机盐来考察膜的盐截留性能。结果表明,在纳滤膜表面成功聚合了复合薄层,并具有良好的亲水性。复合纳滤膜对Na_2SO_4的截留率达到97%,水通量达27.2 L/(m~2·h),可作为一种性能优异的纳滤膜用于无机盐的去除。     

中空纤维纳滤膜制备与应用研究进展

中空纤维纳滤膜虽具有比表面积大、填充密度高以及可通过反洗减轻膜污染等优势，但是在工业领域应用程度却不及平板纳滤膜。其原因是中空纤维具有高弧度的表面特性，纳滤分离层易出现成膜不均、与基膜结合不强等问题，致使中空纤维纳滤膜规模化制造工艺难度提升。本文从制备与改性、工艺优化和应用三个方面综述了近年来国内外中空纤维纳滤膜的研究进展，通过分析不同制膜方法的特性，探讨制膜过程的技术难点与相应研究进展，为推进中空纤维纳滤膜相关研究提供参考。     

芳香聚酰胺纳滤膜的制备及性能研究

以芳香聚酰胺为原料,采用相转化法制备了芳香聚酰胺纳滤膜,通过正交试验确定了最佳制膜工艺.详细讨论了纳滤膜的分离特性,并对纳滤膜的耐溶剂及抗污染性能进行了初步研究.实验结果表明,所制芳香聚酰胺纳滤膜对无机盐及小分子有机物具有较好的选择分离性能.操作压力为0.4MPa时,该膜对蔗糖的截留率为63.74%,对葡萄糖的截留率为54.36%.膜具有很好的耐溶剂性和抗污染性.     

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。     

Investigation on the enhancement of solvent-resistant nanofiltration membrane performance utilizing PDA-UiO-66@CNT as an interlayer

With the growing complexity of separation systems, the application of thin film composite nanofiltration (TFN) membranes in organic solvent separation faces numerous challenges. To augment its solvent stability, an in-situ constructed dopamine hydrogel doped with UiO-66@CNT was developed as an intermediate layer on a polyetherimide (PEI) ultrafiltration membrane. Subsequent interfacial polymerization on this interlayer led to the formation of a solvent-resistant nanofiltration membrane with a vast covalent bond structure, large specific surface area, and enhanced hydrophilicity. Our findings revealed that when the CNT loading in the UiO-66@CNT composite nanoparticles was 2 wt%, the TFN-U₂C₂ membrane exhibited a maximum pure water flux of 126.32 L/(m²·h) and a methanol flux of 45.45 L/(m²·h). The rejection rates for Congo red aqueous and methanol solutions were 96.88% and 92.14%, respectively. The membrane also demonstrated commendable anti-fouling properties. Remarkably, even after 48 h of immersion in various organic solvents, the membrane retained its morphology and separation efficiency. Compared to the TFN-U₂ membrane without CNT addition, the enhancement in separation performance was considerably significant. Hence, this membrane has significant potential for application in treatment of wastewater containing organic solvents and is promising in related fields.     

石墨烯量子点纳滤膜的仿生修饰及稳定性研究

亲水修饰是提高纳滤膜抗污染性能的重要方法。采用氯化胆碱（ChC）对石墨烯量子点（GQDs-TMC）纳滤膜进行后处理仿生修饰,模拟细胞膜上磷酰胆碱的两性离子抗污染表面。红外光谱（FTIR）和表面元素分析（EDS）表明ChC以共价键结合在纳滤膜分离层上。提高反应温度和氯化胆碱溶液浓度,可以增加纳滤膜的仿生修饰程度。ChC的季铵基团与GQDs-TMC纳滤膜分离层羧基基团形成两性离子结构,提高了仿生修饰（GQDs/ChC-TMC）纳滤膜的亲水性,降低了表面电势,提高了对染料分子和二价盐离子的截留率,并且显著增强了抗污染性能。经过酸、碱和氧化剂溶液浸泡处理及高温纳滤膜分离实验,GQDs/ChC-TMC纳滤膜的渗透率和截留率均未发生较大改变,表明仿生纳滤膜具有优异的化学稳定性和耐热稳定性。     

Preparation of highly selective nanofiltration composite membranes based on a novel soluble rigidly contorted monomer

Nanofiltration composite membranes with high selectivity are one of the most critical cores in water treatment, and regulating the surface charge and pore structure of active separation layers in thin film composite membranes is one of the most effective means to improve the selectivity of composite membranes. This article synthesized a novel monomer with positive charge and a rigid twisted Tröger's base structure (named TBDA-SO₃), which was manipulated to improve the microporous structure and surface charge of the composite membrane. By interfacial polymerization, TBDA-SO₃, and piperazine were co-reacted with trimesoyl chloride to successfully prepare positively charged, highly selective, and strongly microporous polyamide composite nanofiltration membranes. The best-performing composite nanofiltration membrane in this article has a permeability similar to that of the control group's poly(piperazine amide) (PPA) membrane (pure water flux, 7.8 L m⁻² h⁻¹ bar⁻¹), but has excellent divalent cation selectivity (52.57), which is 4.4 times that of the control group's PPA membrane.     

用于混合一价盐分离的纳滤膜的制备及性能研究

针对有机颜料废水中单价相似离子（例如CH₃COO^-和Cl^-）分离难的问题,以表面活化能与脱水现象协同作用的分离机制为指导,在界面聚合中加入3,5-二氨基苯甲酸（DMA）来调控孔径、电性等性质,制备对醋酸根和氯离子具有高选择性的复合纳滤膜。XPS结果表明DMA参与界面聚合反应,形成疏松选择层;Zeta电位表明膜表面负电性增强。通过pH、操作压力等条件优化,得出0.6%（质量） DMA-TFC膜性能最佳,水通量较未改性复合膜提高44%,对于醋酸钠与硫酸钠的分离比达到15.0。本工作为相似离子分离纳滤膜的设计与制备提供了理论和实践基础,在颜料废水等水处理、物料分离等领域展现了良好的应用前景。     

Nanofiltrationsmembranen für Trennprobleme in organischen Lösungen

Nanofiltration Membranes for Separation Problems in Organic Solutions . Nanofiltration based on rejection and flux features intermediate between those ultrafiltration and reverse osmosis is one of the technically and scientifically interesting membrane processes with a great future. Moreover, most commercial available nanofiltration membranes are only suitable for separation processes in aqueous solutions. A small number of composite membranes with a highly cross-linked selective layer show a technically interesting resistance towards organic solvents, such as ketones, esters, ethers or alcohols. The present article describes such nanofiltration membranes used for separation of low molecular weight chemical compounds from polar or nonpolar solvents, but also for the removal of organic compound from aqueous solutions. Methods of manufacturing and modifying such solvent stable composite membranes are shown, as are the conditioning of membranes and examples of industrial application.     

Selective filtration of dye by tannic acid-molybdenum disulfide composite nanofiltration membrane

Dye-selective nanofiltration membranes have great potential for chemical dye separation and purification as well as dye wastewater treatment. Two-dimensional materials such as molybdenum disulfide (MoS₂) with excellent physical and chemical properties are ideal nanofiltration membrane materials. MoS₂ with few layers is used in combination with polyphenols to prepare highly selective filtration nanofiltration membranes for cationic dyes. The tannic acid (TA)-MoS₂ composite material is constructed on the surface of a micro-porous Mixed Cellulose Ester membrane by a vacuum filtration method, and the nanofiltration membrane exhibits good flexibility and excellent film-forming properties. The maximum filtration efficiency of TAMoS₂ nanocomposite film for R6G can reach 80%, while for EY and MO, it is only 9.6% and 6.1% respectively. Filtration studies on mixtures of two different types of dyes show that the composite nanofiltration membrane has excellent separation performance. The separation characteristics and mechanism of the composite nanofilm on dyes are carefully studied, showing good selectivity for cationic dyes, which can be ascribed to the synergistic effect of non-covalent interactions and steric hindrance. This work paves the way for the use of eco-friendly membranes for water and wastewater treatment and provides an environmentally friendly solution for various applications.     

Comparison Between Polydimethylsiloxane and Polyimide-Based Solvent-Resistant Nanofiltration Membranes

Nanofiltration using solvent-resistant membranes has become an important separation technology. Polydimethylsiloxane and polyimide are important materials for preparation of solvent-resistant nanofiltration (SRNF) membranes. In this study, the performance of commercial polydimethylsiloxane and polyimide SRNF membranes (as a trademark of MPF and STARMEM) with molecular weight cutoff values of 200–700 Da was compared in terms of organic solvent preconditioning effect, solvent compatibility, solvent flux, and solute rejection. Organic solvents employed were methanol, toluene, ethyl acetate, dichloromethane, and acetone and the organic solutes in a molecular weight range of 160–850 Da were used. Membrane preconditioning with different organic solvents did not affect membrane performance of the polydimethylsiloxane-based MPF membranes but had a significant influence on the polyimide-based STARMEM membranes. Both MPF and STARMEM membranes are not compatible in dichloromethane. MPF membranes were inert to the organic solvents and had relatively low solvent fluxes. STARMEM membranes were highly swollen in methanol and offered much higher solvent fluxes and attractive NF performance in toluene.     

Separating Cyanide from Coke Wastewater by Cross Flow Nanofiltration

Investigations on separation of cyanide from coke wastewater were carried out in a cross flow nanofiltration membrane module following microfiltration of real industrial wastewater. Different composite polyamide nanofiltration membranes were used in the system while studying their effectiveness in cyanide separation under different operating conditions. Transmembrane pressure, pH, and cross flow velocity exhibited strong influence on percentage removal of cyanide. 94% cyanide rejection with a permeate flux of 79 liters per hour at a transmembrane pressure of 13 kg/cm² and at a volumetric cross flow rate of 700 liters per hour was achieved. The membrane module with a composite membrane having high negative charge was successfully operated without any significant loss in flux even after 72 hours operation. These encouraging results show that microfiltration and nanofiltration with properly selected membranes in an appropriate module could lead to a practical solution to a longstanding problem of cyanide removal from industrial wastewater.     

Preparation and separation properties of polyamide nanofiltration membrane

Utilizing an interfacial polymerization technique for the preparation of a polymeric composite nanofiltration membrane, both high permeation flux of water and high salt rejection can be achieved. Synthesis conditions, such as concentration of monomer, reaction time, and swelling agent, significantly affected the separation performance of composite membranes. The composite polyamide membrane had a permeation rate of ～2–5 gallon/ft²/day (gfd) and a salt rejection rate of ～94–99% when 2000 ppm aqueous salt solution was fed at 200 psi and 25°C. Also, a higher performance nanofiltration membrane could be prepared by suitably swelling the support matrix in the period of polymerization. The results of various feed concentrations showed that permeate flux decreased with increasing salt concentration in the feed solution. This result may be due to concentration polarization on the surface of polyamide membranes. The separation performance of polyamide membranes showed an almost independent relationship with operation pressure until it was up to 200 psi. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1112–1118, 2002