羧甲基纤维素钠复合纳滤膜的制备与性能表征

以羧甲基纤维素钠(CMC)为活性层铸膜液,聚砜(PSF)超滤膜为基膜,戊二醛(GA)水溶液为交联剂,采用涂敷和交联的方法制得一种新型荷负电复合纳滤(NF)膜。测定了复合膜的截留相对分子质量,并对其表面形貌进行了表征。在铸膜液中添加质量分数为3.5%的不同种类有机小分子,研究了其对复合膜截留性能的影响。CMC/PSF复合膜对几种无机盐的截留顺序为:Na2SO4>NaCl>MgSO4>MgCl2。     

高性能聚砜中空纤维纳滤膜基膜的研制

采用干-湿法工艺制备聚砜基膜,研究了聚砜铸膜液中聚砜含量、添加剂种类、溶剂组成及含量和凝固浴温度对膜性能的影响。研究结果表明,铸膜液中聚砜含量和添加剂含量对膜性能影响较大;使用混合溶剂可有效改善膜的孔结构和提高聚砜基膜的性能;控制凝胶浴温度可以得到较高性能的基膜。通过选择最佳铸膜液组成及工艺条件,可以制备较高性能的基膜。     

高性能工业用聚砜平板复合膜的制备

考察了浸没沉淀相转化法制备高性能工业用聚砜(PSF)平板复合膜的影响因素,确定N-甲基吡咯烷酮(NMP)/水为溶剂/非溶剂体系,铸膜液中聚砜的质量分数为12%~16%,基膜1作为复合膜的支撑层基膜,利用聚乙烯吡咯烷酮K30(PVPK30)和氯化锂(Li Cl)组成的复合添加剂及PSF/PVP/Li Cl/NMP质量比为15/5/3/77组成的铸膜液制备的聚砜平板复合膜,用于石化废水处理,COD和浊度去除率分别为79.5%和96.8%,水通量为167.2 L/m2·h,废水处理效果明显,膜通量衰减慢,抗污染能力强。     

高通量反渗透膜基膜的制取研究

以聚砜(PSF)为溶质,N-甲基吡咯烷酮(NMP)为溶剂,聚乙二醇(PEG)为添加剂制备铸膜液。一定温度下,通过调节PSF含量、PEG的相对分子质量和添加量,研究不同的铸膜液组成对基膜水通量、截留率、水接触角、耐压密性和膜截面结构的影响。结果表明,基膜的水通量随PSF含量的增加而降低,截留率升高但幅度较小,耐压密性增强。同一相对分子质量的PEG随着PEG含量的增加,通量先增加后减小,截留率变化不大,耐压密性先减小后增大但最终耐压密性低于初始耐压密性。同一含量的PEG随着其相对分子质量的增加,通量呈先增加后减小趋势,截留率变化不大,耐压密性呈减小趋势。综合考虑,选择PSF、NMP的质量分数分别为21%、71%,质量分数8%的PEG-2000作添加剂改性PSF基膜为好。     

一种新型共混复合纳滤膜的制备及性能研究

以海藻酸钠(ALG)和羧甲基纤维素钠(CMC)共混液为活性层铸膜液,聚砜(PSF)超滤膜为基膜,环氧氯丙烷(ECH)的乙醇溶液为交联剂,采用涂敷和交联的方法制得一种新型复合纳滤膜,利用红外光谱仪、扫描电子显微镜、原子力显微镜和接触角测量仪等检测手段对复合膜进行了结构和性能的表征。结果表明,在1.0 MPa压力和30 L?h-1料液流量操作条件下,该复合纳滤膜对1000 mg?L-1 Na2SO4溶液的截留率为97.1%,通量17.3 L?m-2?h-1。以ALG和CMC共混液制备的复合纳滤膜比单一材料膜有更致密的膜面结构,截留率更高。该纳滤膜对不同无机盐的截留性能不同,表现出荷负电膜截留性能,这主要决定于荷电膜与电解质离子之间的静电作用力。     

铸膜液中水含量对聚砜超滤膜结构和性能的影响

试验在环境温度20℃、相对湿度50%、凝胶浴温度20℃的条件下制膜,在聚砜(PS)铸膜液中添加水为非溶剂添加剂,研究水添加量对铸膜液粘度、膜性能和结构的影响.结果表明,水的添加对铸膜液起到了增粘的作用;30℃ PS的质量分数为14%铸膜液所成膜的纯水通量随铸膜液中水的添加量的增加大体上呈增加的趋势,从59.1增大到126.4 L·m~(-2)·h~(-1);截留率则略有下降;相应的膜表面的孔径增大、孔增多;相同水添加量(质量分数0.05%)PS的质量分数为14%的铸膜液粘度随温度的升高而减小;铸膜液温度的升高,相应的膜的纯水通量随之增加,截留率则略有下降.     

N,O-羧甲基壳聚糖/聚砜复合纳滤膜的制备及性能研究

以聚砜(PsF)超滤膜为基膜、N,O-羧甲基壳聚糖(NOCC)水溶液为活性层铸膜液、戊二醛(GA)为交联剂,采用涂敷和交联的方法制备了复合纳滤膜.测试了膜表面的流动电势(E)随操作压力(△P)的变化,实验结果表明在电解质溶液中,NOCC/PSF复合NF膜表面荷负电.对其结构和形貌进行了表征,并研究了有机小分子添加剂对复合膜截留性能的影响.NOCC/PSF复合NF膜对几种无机盐的截留顺序为Na2S04＞NaCl＞MgSOa＞MgCl2,呈现出荷负电纳滤膜的截留特征.     

聚砜中空纤维膜的亲水改性研究

将吐温80或磺化聚砜(SPSF)加入聚砜-聚乙二醇400-二甲基乙酰胺(PSF–PEG400–DMAc)体系,共混制成均一铸膜液,采用浸入沉淀相转化法制备聚砜中空纤维超滤膜,考察吐温80或SPSF对聚砜中空纤维膜的亲水改性效果。对膜结构、铸膜液黏度、纯水通量、截留率、拉伸强度等进行了表征。研究结果表明,SPSF相比吐温80对膜的亲水性改善更明显。当SPSF质量分数为1.5%时,就可将PSF中空纤维膜的纯水通量提高一倍以上,膜纯水通量达到302 L/(m~2·h),对牛血清白蛋白(BSA)的截留率达到93%。     

戊二醛交联的壳聚糖硫酸酯/聚砜复合纳滤膜的制备及截留特性

采用均相合成的方法制备了一种典型的两性聚电解质--壳聚糖硫酸酯(SCS).以SCS的水溶液为复合纳滤膜活性层铸膜液,戊二醛为交联剂,聚砜超滤膜为基膜,采用涂敷与交联的方法制备了壳聚糖硫酸酯/聚砜(SCS / PSF)复合纳滤膜,采用环境扫描电镜(ESEM)对其表面和断面结构进行了表征, 并研究了活性层铸膜液的组成及制备条件对复合膜截留性能的影响.所制得的复合NF膜在13～15℃、0.30 Mpa下,对1000 mg·L-1Na2SO4和NaCl 溶液的截留率分别为91.2%、48.5%,通量分别为3.2、6.7 kg·m-2·h-1.SCS/PSF 系列复合膜对无机盐的截留顺序为: Na2SO4 ＞ NaCl ＞ MgSO4 ＞ MgCl2.实验结果表明SCS/PSF复合膜表面活性层因吸附电解质溶液中的阴离子而荷负电,并由此决定其对无机盐的截留性能.     

壳聚糖/聚砜复合中空纤维膜的制备及其CO2/N2分离性能研究

以壳聚糖(CS)为涂层材料,聚砜(PSf)为基膜材料,运用浸渍涂覆的方式制备了壳聚糖/聚砜复合中空纤维膜,考察了壳聚糖质量分数、涂覆时间以及操作温度和压力对CO2、N2的渗透分离性能的影响。结果显示,在聚砜基膜上涂覆壳聚糖材料后,可有效提高CO2/N2分离系数;CO2、N2的渗透速率符合Arrhenius关系式;CO2在复合中空纤维膜中的渗透由溶解-扩散和促进传递两方面主导,而N2的渗透符合溶解-扩散模型。     

纳米聚苯胺改性聚哌嗪酰胺纳滤膜的制备

以导电态纳米聚苯胺(PANI)为添加剂, 哌嗪和均苯三甲酰氯(TMC)为反应单体, 通过界面聚合反应在聚砜超滤膜上形成复合层制备纳滤膜。采用扫描电子显微镜(SEM)和原子力显微镜(AFM)等对复合膜的性能和结构分别进行了测试和表征。SEM照片证实PANI含量低时, 可以在复合膜上分布得比较均匀;AFM图像看出膜表面粗糙度的增加;膜性能的测试结果证实了添加PANI的复合膜水通量得到了提高, 同时脱盐率也有变化。最优实验条件下, 膜对Na₂SO₄、MgSO₄、MgCl₂和NaCl的截留率分别为99.4%、98.5%、85.4%和59.2%。试验结果表明, 加入PANI能够提高膜的水通量, 并提升了膜的脱盐性能。     

磺化聚醚酮复合纳滤膜的制备

以含酞侧基聚芳醚酮（PEK—C）超滤膜为底膜,以磺化聚芳醚酮（SPEK—C）为复合膜涂层的功能材料制备了复合纳滤膜,研究了制备条件,包括SPEK—C含量、磺化度、固化温度和时间对复合纳滤膜性能的影响,还考察了该复合纳滤膜对不同无机盐的分离性能以及耐热性能。     

Novel charged chitosan composite nanofiltration membranes containing chiral mesogenic group

To improve the performance of nanofiltration (NF) membranes, a chiral mesogenic compound, a positively charged compound, and a negatively charged compound were grafted to chitosan, respectively. Series of novel composite NF membranes were prepared by over‐coating the polysulfone ultrafiltration membrane with the mixture of chitosan and modified chitosan. The chiral mesogenic compound, the positively charged compound, the negatively compound and their chitosan derivatives were characterized by infrared spectrophotometer, differential scanning calorimetry, polarized optical microscope; the structure of the membrane was characterized by scanning electron microscopy. The performance of composite NF membranes was strictly related to the novel compounds grafted to chitosan and its composition. The rejection reached the maximum of 95.7% for CaCl₂ with P_2‐7 composite NF membrane, corresponding flux was 3155 Lm^?2h^?1. The rejection reached the maximum of 93% for Na₂SO₄ with P_3‐5 composite NF membrane, corresponding flux was 3879 Lm^?2h^?1. Comparing with conventional NF membranes, the membranes were used in low pressure with high flux, especially for the separation of high‐valence ions from solution. The membranes were typical charged NF membranes. POLYM. ENG. SCI., 57:22–30, 2017. © 2016 Society of Plastics Engineers     

Fabrication of polyamide thin film nanocomposite reverse osmosis membrane incorporated with a novel graphite-based carbon material for desalination

The properties of polyamide (PA) thin film composite (TFC) membranes are affected by many variables, especially the additives in the process of interfacial polymerization that play an important role in the properties of membranes. In this study, a new type graphite carbon was added into organic phase containing trimesoyl chloride for interfacial polymerization with aqueous phase containing m-phenylenediamine to prepare modified polyamide thin film nanocomposite (TFN) membranes for reverse osmosis (RO) adhibition. Polysulfone ultrafiltration membranes were used as the carrier of the interfacial polymerization. The concentration of graphite carbon was selected from 0.002 to 0.01 wt%. The polyamide nanocomposite membrane prepared with the concentration of 0.004 wt% graphite carbon showed the best RO desalination performance, which the water flux of this TFN membrane is over 2.3 times as much as pristine TFC membrane, and the salt rejection is over 99%. This article provides a well-performing polyamide thin film nanocomposite membrane modified by a new-type carbon nanoparticles consequently.     

集成膜技术处理微污染水的工艺研究

采用0.45μm微滤膜、不同截留分子质量的超滤膜(100、80、50,30.10、5 kDa)以及不同型号的纳滤膜(NF90、NF270、NF70)为试验用膜,并将这些膜进行优化组合,直接处理浙江省某流域河水.结果表明,采用0.45μm微滤膜、截留分子质量5kD的超滤膜作为预处理工艺,经NF90处理后,COD_(Mn)去除率达到89%,离子的去除率达到83%.采用直接膜处理工艺,可用微滤、超滤替代传统给水处理中的混凝、过滤、沉淀及澄清处理等微污染水预处理工艺,集成膜分离技术能很好地实现对微污染原水的彻底处理,出水水质稳定安全,完全达到健康饮用水标准.     

Preparation and characterization of carboxylated multiwalled carbon nanotube/polyamide composite nanofiltration membranes with improved performance

Polyamide thin‐film composite nanofiltration (NF) membranes were prepared via the interfacial polymerization (IP) process of piperazine and 1,3,5‐trimesoyl chloride on the polysulfone/nonwoven fabric ultrafiltration membrane surface. Carboxylated multiwalled carbon nanotubes (cMWNTs) were incorporated into the aqueous phase during the IP process to improve the membrane performance. The composition and morphology of the membrane surface were examined by means of attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy–energy dispersive spectrometry, and atomic force microscopy. The effects of the cMWNTs content on the membrane hydrophilicity, separation performance, and antifouling properties were characterized through water contact angle and crossflow filtration measurements. The experimental results show that membrane surface hydrophilicity, water permeability, salt rejection (R ), and antifouling properties all improved. In particular, when the cMWNTs content was 50 ppm, the magnesium sulfate R of the composite NF membrane reached a maximum value of 98.5%; meanwhile, the membrane obtained an obviously enhanced water flux (62.1 L m^?2 h^?1 at 0.7 MPa), which was two times larger than that of the original NF membrane. The modified NF membranes showed enhanced antifouling properties; this was mainly attributed to changes in the microstructures and surface features of the polyamide layer after the addition of the cMWNTs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45268.     

A Compatible Membrane Process for Separation and Concentration of Pediocin PA-1 from Fermentation Broth

This work describes an effective combined ultrafiltration (UF)-nanofiltration (NF) membrane process for the separation and concentration of pediocin PA-1 from fermentation broth. Three polysulfone (PS) membranes with MWCOs of 5, 10, and 30 kDa were tested for ultrafiltration effectiveness. The 10 kDa membrane was selected because it displayed high permeability, good pediocin PA-1 recovery and reduced fouling. When the volume concentration factor (VCF) of UF reached 2.5, continuous diafiltration (DF) was carried out. The optimal diafiltration factor (DFF) was 1. The permeate obtained from UF was then concentrated by NF. When the VCF of NF reached 4.5, pediocin PA-1 recovery loss was only 10.5%. This two-stage membrane process improved the loading solutions by 4.5-fold, allowing up to 71.6% recovery of pediocin PA-1. After the membrane process, the NF retentate could be concentrated and subjected to preparative chromatography to obtain purified pediocin PA-1, or it could be dried to obtain a rich pediocin PA-1 preservative.     

High flux and rejection with chiral chitosan composite nanofiltration membranes: Preparation and characterization

Two series of novel composite nanofiltration (NF) membranes were prepared by the overcoating of polysulfone ultrafiltration membranes with a mixture of chitosan and chitosan derivatives modified with two different chiral compounds. The two chiral compounds and their chitosan derivatives were characterized by IR spectroscopy, differential scanning calorimetry, and polarimetry. The structure of the membrane was characterized by scanning electron microscopy (SEM). The rejection and flux of the composite NF membranes were strictly related to the chiral compound grafted to chitosan and its composition in the mixture. An extremely high rejection, 98.23%, was observed with P_2–3 of the polymer (P₂) composite NF membrane, and the flux remained as high as 351 L m^?2 h^?1 at 0.4 MPa with 1000 mg/L NaCl. These results, together with SEM and IR images of the composite NF membrane, indicated that the chiral compound structure was crucial for the structure and function of the composite membrane. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

聚乙烯醇-SiO2/聚酯无纺布膜的制备及性能研究

采用聚酯无纺布(PET)作为支撑层,利用相转换法在PET表面制备聚乙烯醇(PVA)或PVA-SiO₂活性层,得到了PVA/PET复合膜与PVA-SiO₂/PET复合膜。考察了2种复合膜的过滤性能和污染行为。结果表明,PVA中加入质量分数4%纳米SiO₂颗粒,复合膜的接触角降至33.1o,亲水性显著增强,而膜孔径减小至3.1 nm,降低了85.5%,PVA/PET超滤膜转变为PVA-SiO₂/PET纳滤膜(0.6 L/(m²·h))。PVA-SiO₂/PET复合纳滤膜对海藻酸钠的抗污染性能较强。纳米SiO₂对复合膜的污染机制无明显影响,模拟污染物对复合膜的污染机制以标准堵塞为主。     

Solution blown sulfonated poly(ether sulfone)/poly(ether sulfone) nanofiber‐Nafion composite membranes for proton exchange membrane fuel cells

A composite membrane of sulfonated poly(ether sulfone) (SPES)/poly(ether sulfone) (PES) nanofiber (NF) mat impregnated with Nafion was prepared and evaluated for its potential use as a proton conductor for proton exchange membrane (PEM) fuel cells. The supporting composite nanofibrous mat was prepared by solution blowing of a mixture of SPES/PES solution. The characteristics of the SPES/PES NF and the composite membrane, such as morphology, thermal stability, and performance of membrane as PEMs, were investigated. The performance of composite membranes was compared with that of Nafion117. The introduction of solution blown NFs to composite membranes modestly improved proton conductivity, water swelling, and methanol permeability. Therefore, composite membrane containing SPES/PES NFs can be considered as a novel PEM for fuel cell applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42572.