水溶性荧光染料溶液脱盐浓缩的纳滤实验研究

选用NTR7450和NF270两种纳滤膜对水溶性工业荧光染料原液进行分离，选择出透过通量大、除盐效果好和染料截留率高的纳滤膜，并对该染料溶液进行了脱盐和浓缩的间歇渗滤过程研究：在温度25℃和压力1.0MPa下，膜对染料截留率达到100％，最终料液中NaCl浓度从0.214mol／L降到0.0025mol／L,料液被浓缩了2．6倍。说明纳滤膜的间歇渗滤操作过程能够实现染料溶液的脱盐浓缩。     

纳滤膜-间歇渗滤法进行染料脱盐与浓缩的实验研究

根据纳滤膜的截留相对分子质量和对盐具有一定的截留率,针对一种商品代号为对ORD-HPDT的染料所需脱盐和浓缩要求,进行了纳滤膜的筛选和纳滤膜-间歇渗滤操作实验研究.结果表明,选用合适的纳滤膜,采用间歇渗滤法处理该染料溶液,不仅脱盐效果较为理想,而且染料质量分数也从3%浓缩至6%,因而技术上是可行的.     

纳滤膜脱盐浓缩染料的研究

考察了料液中盐的浓度对ＣＡ和ＰＡ纳滤膜性能的影响。随着料液中盐浓度的增加,膜的截留率减小,通量减小,ＣＡ膜的脱盐性能优于ＰＡ膜,本文选用脱盐性能较佳的ＣＡ纳滤膜进行了染料连续浓缩脱盐试验。ＣＡ膜对染料的截留率大于９９．９％,总脱盐率为５１％。在浓缩过程中染料的浓度提高了２．７６倍。     

聚酰胺非对称纳滤膜在印染废水深度处理中的应用

利用自制的聚酰胺非对称纳滤膜处理水溶性阴离子染料废水,并与NF270商品膜性能进行了比较研究。在0.7 MPa和25℃的条件下,所制纳滤膜对3种阴离子染料的截留率均大于95%。24 h染料连续脱盐运行条件下,膜的水通量保持在50 L.m-2·h-1,染料截留率96%以上,脱盐率稳定在5%以下,具有较好的选择分离性和耐污染性。2种纳滤膜的性能对比研究表明,所制PMIA非对称纳滤膜的染料截留能力和耐高温性优于NF270商品膜,但膜通量稍低。     

纳滤膜脱盐性能及其在海水软化中应用的研究

选择了ESNA1型纳滤膜对NaCl、MgCl2、Na2SO4、MgSO4等4种无机单盐水溶液体系进行分离实验;考察操作压力和料液浓度等的变化对纳滤膜分离性能的影响及纳滤膜脱盐的稳定性,得到一些纳滤膜脱盐的规律;并对ESNA1膜在人工海水和海水软化脱盐中的应用作了初步探索.无机盐体系脱盐实验结果显示:随操作压力升高和料液浓度增大,ESNA1膜对4种盐溶液中的离子的截留率分别增大和减小,操作压力和料液浓度的变化对一价盐溶液的截留率影响较大,对二价盐溶液的截留率影响较小.人工海水和海水软化脱盐试验结果显示:ESNA1纳滤膜在实验过程中稳定性好,在较低的操作压力下膜通量也较高,且ESNA1纳滤膜对Ca2 、Mg2 、SO42-离子的截留率均＞90%,初步判断此种纳滤膜可用于海水软化预处理.     

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。     

对纳滤膜分离净化湿法磷酸溶液影响因素的研究

选择NP010和NP030两种纳滤膜对含MgSO_4、Fe_2(SO_4)_3、Al_2(SO_4)_3的磷酸溶液进行分离净化试验,考察了盐含量、操作压力、料液温度等对纳滤膜分离性能的影响。结果表明:随盐含量的增大,纳滤膜的通量减小,其对盐的截留率亦下降;随操作压力的增大,纳滤膜的通量增大,截留率也随之增大,但在压力较高时,截留率增大趋势不明显;料液温度上升,纳滤膜的通量上升,截留率下降;在不同盐含量、操作压力、料液温度的条件下,两种纳滤膜对P_2O_5的截留率均在5%以内。     

纳滤膜在染料生产废水处理中的应用

采用超滤、纳滤集成技术,对高盐度、高色度、高COD的染料生产废水进行中试处理试验,分别考察了恒容脱盐、恒压浓缩、连续化处理等不同工艺的效果。结果表明,纳滤膜对COD的去除率大于90％,对色度去除率基本为100％,对染料截留率大于97％,能有效截留废水中的染料和有机物。同时一价盐（NaCl）大部分能透过膜。     

无机盐水溶液体系的纳滤膜分离实验研究

选择了NF45和SU200两种纳滤膜对1－1型（KC1、NaCl、LiCl)、2－1型MgCl2)、1－2型（K2SO4）及2－2型（MgSO4)等6种无机盐水溶液体系进行分离实验；考察了纳滤膜分离性能随操作压力、料液浓度及电解质种类等因素的变化所受到的影响。实验结果表明，纳滤膜对盐的截留率随操作压力的增加而增大，并趋向于定值（即膜的最大截留率，又称为膜的反射系数）；纳滤膜对盐的截留率随电解质种类的不同而改变，随盐浓度的增大而下降，但当盐浓度很高时，截留率趋向于一定值，该值并不等于0，说明与纳滤膜的孔径相比，不可忽视电解质离子大小的影响。     

用纳滤技术对染料溶液脱水除盐的研究

简单介绍了纳滤膜的特性 ,详细介绍了纳滤膜对染料脱水除盐的情况和操作参数对膜性能的影响 ,并略谈了染料脱水除盐选择膜分离设备规格型号的观点。     

基于化工废水处理中纳滤膜的应用研究

作为一种新型分离技术,纳滤膜不仅能有效净化废水,还能回收其中的有用物质。因此,在化工废水处理中得到多数企业的认可。文章介绍了纳滤膜分离技术的特点与纳滤膜的分离机理。并以陶氏NF270-4040纳滤膜处理盐化工废水为基础,从考察操作压力、温度、进水流量、进水pH入手,依据非平衡热力学模型分析纳滤膜处理化工废水的优势及适宜条件。     

纳滤/反渗透膜处理重金属废水的性能

The performance of different nanofiltration （NF） and reverse osmosis （RO） membranes was studied in treating the toxic metal effluent from metallurgical industry. The characteristics and filtration behavior of the processes including the wastewater flux, salt rejection and ion rejection versus operating pressure were evaluated. Then the wastewater flux of RO membrane was compared with theoretical calculation using mass transfer models, and good consistency was observed. It was found that a high rejection rate more than 95% of metal ions and a low Chemical Oxygen Demand （COD） value of 10 mg·L^-1 in permeate could be achieved using the RO composite membrane, while the NF rejection of the salt could be up to 78.9% and the COD value in the permeate was 35 mg·L^-1. The results showed that the product water by both NF and RO desalination satisfied the State Reutilization Qualification, but NF would be more suitable for large-scale industrial practice, which offered significantly higher permeate flux at low operating pressure.     

水处理中膜分离技术的应用

对水处理膜分离技术的发展历史和应用现状做了介绍,总结了国内外纳滤和反渗透技术在海水苦咸水淡化、废水处理等水处理领域的应用,指出了膜污染、浓差极化现象及成本较高等膜技术应用中普遍存在的问题。由于纳滤膜具有选择透过性,对纳滤技术应用于盐湖卤水资源开发中镁锂分离过程的可行性做了探讨,并从膜原件和配套工艺两方面对相关技术的应用做了展望。     

Advances in Polymeric Nanofiltration Membrane: A Review

The nanofiltration membrane was first introduced during late 1980s possessing properties between reverse osmosis and ultrafiltration membrane. Nanofiltration membranes have been used for applications including food industry, pharmaceutical, wastewater treatment, and desalination. This review presents an inclusive outlook of recent research and advances in polymeric nanofiltration membrane technology. Various methods were reported for nanofiltration membrane preparation particularly through electron beam irradiation, UV/photografting, layer by layer, plasma treatment, interfacial polymerization, and nanoparticle incorporation. Nanofiltration membranes were reported to remove microorganisms, turbidity, dissolved salts, and hardness. Major problem in application is nanofiltration membrane fouling, thus efforts regarding fouling mitigation are discussed.     

Sub-20 nm Bilayer Hydrophilic Poly(Vinyl Pyrrolidone) Coatings for Antifouling Nanofiltration Membranes

Fouling is a major concern in membrane technology. Neutral hydrophilic coatings alleviate fouling on membrane surfaces by passively resisting the adsorption of foulants without altering the properties of membranes. Coatings, however, often result in a trade-off of reduced water flux. Ultrathin hydrophilic coatings could minimize the influence on water flux, but its fabrication is challenging via traditional methods. Here, fabrication of sub-20 nm bilayer hydrophilic coating is reported that is grafted onto nanofiltration (NF) membranes via a one-step initiated chemical vapor deposition (iCVD) method. The iCVD coating is conducted by conformally depositing a crosslinked poly(vinyl pyrrolidone-co-ethylene glycol dimethacrylate) bottom layer on pretreated NF membrane, followed by in situ grafting of poly(vinyl pyrrolidone) homopolymer to further improve surface hydrophilicity. Both thickness and crosslinking degree of the bottom coating are systematically tailored to reduce its side effects on permeation rate and salt rejection. The modified NF membranes exhibit 99% lower microbial adhesion compared to the pristine membrane, with minor impact on permeation and salt rejection performance. The coating is also stable against continuous ultrasonication. The reported method is thus expected to shed light on facile novel ways of reducing membrane fouling in desalination and industrial wastewater treatment.     

Green and feasible fabrication of loose nanofiltration membrane with high efficiency for fractionation of dye/NaCl mixture by taking advantage of membrane fouling

Loose nanofiltration membrane emerges as required recently, since it is hard for conventional nanofiltration membrane to fractionate mixture of dyes and salts in textile wastewater treatment. However, the polymeric membranes unavoidably suffer from membrane fouling, which was caused by the adsorption of organic pollutants (like dyes). Normally, the dye fouling layer will shrink membrane pore size, thus resulting in flux decline and rejection increase. It is thought that membrane fouling may be a double-edged sword and can be an advantage if properly utilized. Thereby, loose nanofiltration membranes were constructed here by a green yet effective method to fractionate dyes/salt mixture by taking advantage of membrane fouling without using poisonous ingredients. A commercially available polyacrylonitrile (PAN) ultrafiltration membrane with high permeability was chosen as the substrate, and dyes were used to contaminate PAN substrate and formed a stable barrier layer when adsorption of dyes reached dynamic equilibrium. The resultant PAN-direct red 80 (DR80) composite membranes displayed superior permeability (~128.4 L m⁻² h⁻¹) and high rejection (~99.9%) to DR80 solutions at 0.4 MPa. Moreover, PAN-DR80 membranes allowed fast fractionation of dyes/sodium chloride (NaCl) mixture, which maintained a negligible dye loss and a low NaCl rejection (~12.4%) with high flux of 113.6 L m⁻² h⁻¹ at 0.4 MPa. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47438.     

高通量聚醚砜纳滤膜的制备及对染料浓缩脱盐

以聚醚砜（PES）为膜材料,以嵌段式聚醚 Pluronic F127为添加剂,利用特制刮膜设备通过相转化法制备出高通量PES/Pluronic F127复合纳滤膜,并将其用于染料的浓缩脱盐。研究了添加剂含量、溶剂蒸发温度和蒸发时间对膜结构和膜性能的影响,考察了不同操作压力和操作温度下膜对染料的分离性能。扫描电镜 （SEM）、接触角、孔隙率数据和蛋白吸附测试结果表明,Pluronic F127改善了膜孔结构,提高了孔隙率,并且显著提高了膜的抗污染性能。纯水通量、截留率以及膜表面孔径表征结果表明,当Pluronic F127含量为3%、溶剂蒸发温度为90℃、 蒸发时间为18 s时,膜的分离性能最佳。在0.6 MPa下该膜对低分子量染料的截留率可达99.9%,且通量达到110.2 L·m^-2·h^-1,对NaCl的截留率仅为5.5%。在12 h的染料浓缩脱盐中,膜对染料的通量维持在较高水平且截留率始终保持在99%左右,具有良好的稳定性和抗污染性。