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。     

中空纤维涂敷机制备纳滤复合膜的初步研究

研究制备中空纤维纳滤复合膜的机器化设备-涂敷机.涂敷机应用可编程控制器(PLC)来控制喂丝辊、干燥管、反应管、受丝辊等各个部件,对喷淋时间、卷绕速度、有机相浓度等因素进行控制.试验以截流分子量为20000的聚砜中空纤维超滤膜为基膜,哌嗪水相浓度质量分数为2.0%,均苯三甲酰氯有机相浓度质量分数为0.5%,水相处理时间为40min,涂敷装置的卷绕速度控制在1.356m·min~(-1),界面反应温度控制在45℃,能够连续制备性能优良的中空纤维复合膜.以质量分数0.2%的硫酸镁水溶液,在0.4MPa下测试膜的性能,其脱盐率91.85%,通量30.08L·m~(-2)·m~(-2)h~(-1).     

中空纤维纳滤膜产业化可行性研究

中空纤维膜兼以其填充密度大,占地面积小等优势,自其开发以来迅速占领了一席之地。纳滤膜能够截留离子及小分子有机物等独特的性能,在过去的几十年里发展迅速,成为一种重要的分离纯化技术。中空纤维纳滤膜结合了中空纤维及纳滤膜的优势,是一种还未市场化的新产品。本项目以中空纤维纳滤膜为出发点,引进新加坡国立大学的一体化成膜工艺,旨在建立一条从膜丝的生产到完整的膜组件产品的生产线,年产量将达到1000万。实现产学研结合,该生产线同时还能用于科研实验。     

构建聚酰胺复合纳滤膜中间层的研究进展

薄膜复合(TFC)纳滤膜因其具有分离精度高、运行能耗低等特点被广泛运用于水处理等诸多领域.界面聚合法是制备复合纳滤膜的常用方法,构建位于基膜和聚酰胺(PA)分离层之间的中间层对界面聚合过程中形成的PA层的结构有着重要影响.综述了TFC纳滤膜中间层的最新研究进展,首先介绍了在聚酰胺复合纳滤膜中引入中间层的优势;其次对水溶...     

中空纤维纳滤膜制备方法研究进展

现阶段国内纳滤膜的制备方法主要集中在相转化法和复合法。由于技术的限制,中空纤维纳滤膜的制备还处于实验室阶段。本文主要介绍了现阶段国内中空纤维纳滤膜的制备方法,以及国外中空纤维纳滤膜制备新方法——共挤出一步成型技术。     

低压醋酸纤维素中空纤维反渗透膜及组件研制

本文报导了以二醋酸纤维素(CA)为原料,通过溶液干湿法多孔纺丝制膜技术生产低压中空纤维反渗透膜及组件的研究成果。研制的TF-100型(4″)RO 组件在以自来水为进水,操作压力1MPa,水回收率50%条件下测试;脱盐率为93%,产水量为200 L/h(25℃)。组件可用于自来水和低度含盐水的脱盐。     

中空纤维渗透汽化膜分离研究现状与展望

本文综述了中空纤维渗透汽化膜分离的研究进展,包括中空纤维支撑膜的制备、复合膜的制备方法、中空纤维渗透汽化膜的工业应用和中空纤维渗透汽化膜传质特性等几个方面,对这个方面所存在的问题以及今后发展方向进行了展望.     

非溶剂添加剂对聚醚砜酮中空纤维纳滤膜结构和性能的影响

以新型杂萘联苯聚醚砜酮(PPESK)为膜材料,N-甲基-2-吡咯烷酮(NMP)为溶剂,乙二醇甲醚(EGME)、冰醋酸(AA)以及AA/EGME作为复合添加剂,采用干-湿相转化技术制备了中空纤维非对称纳滤膜,重点考察了非溶剂添加剂对中空纤维膜结构和性能的影响。结果表明非溶剂添加剂的加入导致了中空纤维膜孔结构由指状转变为海绵状,从而引起中空纤维膜性能的变化。当聚合物质量分数为23%,铸膜液溶剂体系为m(AA)∶m(EGME)∶m(NMP)=5.7∶16.5∶54.8时,中空纤维膜对PEG600的截留率高于96%,纯水通量为211 L/(m2.h)。     

New chlorine‐resistant polyamide reverse osmosis membrane with hollow fiber configuration

New asymmetric hollow fiber reverse osmosis (RO) membrane was developed from a new chlorine‐resistant copolyamide [4T‐PIP(30)] with a piperazine moiety by a conventional phase‐separation method. The new 4T‐PIP(30) hollow fiber membrane has the same low‐pressure RO performance as cellulose triacetate hollow fiber membrane (FR = 205 L/m² day, Rj = 99.6%) and superior chlorine resistance as well as pH resistance to conventional aramid RO membranes. Structural analysis and viscoelastic study revealed that the new hollow fiber consisted of a top skin, dense layer, and microporous layer, and that it began to decrease its elasticity at 80°C in water, which is possibly related to its good and stable RO performance around room temperature. Several kinds of RO modules were made from the new hollow fiber membranes, for which RO performances were stable for 2 years in chlorinated feed water desalination (the free residual chlorine ranged from 0.l to 1.1 mg/L). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 517–527, 2001     

沸石/聚酰胺反渗透复合膜的制备

为了提高反渗透膜的通量,通过在界面聚合反应过程中添加NaA型纳米沸石分子筛制备了沸石/聚酰胺反渗透复合膜,采用SEM及复合膜性能测试的方法比较了沸石分子筛添加在水相或者油相中时对膜结构及分离性能的影响.SEM图谱结果表明:沸石分子筛添加在油相中时,沸石在聚酰胺基质中分散均匀,膜结构比较均一;但当沸石分子筛添加在水相中时...     

界面聚合中空纤维正渗透膜的制备和表征

以聚砜为原料,通过浸没沉淀法制备中空纤维基膜,然后采用界面聚合法制备出中空纤维正渗透膜。考察了制膜参数、基膜结构和FO性能三者之间的关系。结果表明基膜的厚度为影响FO性能的主要因素之一。基膜的厚度越厚,FO过程中渗透效率越低。制得PSF中空纤维正渗透膜的厚度为0.129 mm,断裂拉伸力为2.48 N,FO通量为10.3 L·m^-2·h^-1,逆向盐扩散性能为0.15 g·L^-1。     

Nanofiltration thin-film composite membrane on either the internal or the external surface of a polysulfone hollow fiber

The inner and outer surfaces of a porous hollow fiber polysulfone support are compared as substrates for the synthesis of polyamide thin-film composite (TFC) membranes by interfacial polymerization. While both surfaces have pores common of microfiltration membranes, the inner surface has a larger pore diameter than the outer surface (2,700 nm compared to 950 nm). The inner TFC membrane showed higher water nanofiltration permeance than the outer (2.20 ± 0.17 compared to 0.13 ± 0.03 L m⁻² hr⁻¹ bar⁻¹). This was due to the influence of the porosity and roughness, which were different on both support surfaces. These membranes are interesting because they were synthesized in a hollow fiber support with a high membrane area per volume unit (~6,900 m²/m³) and the substrate used was commercial, which means that the TFC membrane obtained is suitable for industrial application. A mathematical simulation of the nanofiltration run with COMSOL Multiphysics 5.3 software confirmed the experimental trends observed.     

界面聚合工艺条件对反渗透复合膜性能的影响

以聚砜超滤膜为支撑膜,间苯二胺(MPD)为水相功能单体,均苯三甲酰氯(TMC)为油相功能单体,通过界面聚合法制备了反渗透复合膜。研究了功能单体浓度、界面聚合反应时间、界面聚合成膜后热处理时间和温度等条件对复合膜分离性能的影响;并对在水相中添加相转移催化剂对复合膜分离性能的影响和相转移催化机理进行了初步探讨。首先在单因素实验条件下确定工艺条件的优化范围,然后经过正交实验得到最佳工艺条件,实验结果表明, 油相中TMC浓度为3 g•L^-1、水相中MPD浓度为20 g•L^-1、界面聚合反应时间为30 s、界面聚合成膜后热处理温度为90 ℃、后处理时间15 min时,所制备的反渗透复合膜表现出良好的分离性能,通量达14.91 L•m^-2•h^-1,截留率为0.951(测试条件: 压力1.6 MPa, 温度25 ℃, NaCl浓度20000 mg•L^-1);当水相中MPD浓度较低时,加入适量的相转移催化剂,能有效地改善膜的分离性能。     

Economic comparison of transverse and longitudinal flow hollow fiber membrane modules for reverse osmosis and ultrafiltration

The presently used hollow fiber membrane modules consist of a bundle of fibers in a cylindrical polymer or metal shell parallel to the shell axis. The feed solution flows either through the lumen or at the outside parallel to the fibers. This paper compares the performance of these modules with a new transverse flow module where the hollow fibers are positioned perpendicularly to the flow direction. For both types of modules the product costs are calculated for desalination by reverse osmosis and Dextran concentration by ultrafiltration. These calculations are based on literature data. The main conclusion is that the application of the tr‘ansverse flow module is only attractive if the permeation resistance is mainly determined by the hydrodynamics (ultrafiltration) and not attractive if the membrane permeability is the main resistance (reverse osmosis).     

Preparation of reverse osmosis composite membrane with high flux by interfacial polymerization of MPD and TMC

In this study, reverse osmosis (RO) composite membrane with extra‐thin separation layer was prepared by the interfacial polymerization (IP) of metaphenylene diamine (MPD) with trimesoyl chloride (TMC) on the surface of polysulfone (PS) support membrane. The properties and structures of skin layer of RO composite membranes were characterized by FTIR and SEM, it was found that IP had occurred and the separation layer was formed. The effects of the monomer concentration on membrane flux and salt rejection were investigated, and the optimum concentration of MPD and TMC were 2 and 0.3% (w/v), respectively. To improve flux, the phase‐transfer catalyst was added to the water phase, and the effects were remarkable when the concentration of MPD was low, in which both salt rejection and flux increased by 20% than initial results. When some of the hydrophilic additives such as alcohols and phenols were added into water phase, the flux of the prepared membrane increased from 13.03 to 33.42 L/(m² h) without loss in salt rejection. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

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     

中空纤维超滤膜在炼化废水回用工程中的优化设计

选择中空纤维超滤膜作为炼化废水回用工程中反渗透系统的预处理工艺,给出了中空纤维超滤系统预处理工艺和膜组件的选择、运行方式和运行参数、反洗和化学清洗周期的优化设计数据,并得到多个实际工程的验证。     

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.