聚醚砜质量分数对聚偏氟乙烯/聚醚砜共混膜性能和结构的影响

用与聚醚砜共混的方法来改善聚偏氟乙烯膜的抗收缩性能,以二甲基乙酰胺作溶剂,聚乙烯吡咯烷酮为添加剂,研究了聚醚砜(PES)质量分数对聚偏氟乙烯/聚醚砜共混膜的收缩率、水通量、截留率及形态结构的影响。聚醚砜的加入可以有效地降低共混膜的收缩率,在w(PES)=1.5%时,共混膜的水通量取得极大值,截留率取得极小值。     

新型聚醚砜-磺化聚醚砜共混膜的性能研究

以浓硫酸为聚醚砜(PES)的溶剂和磺化剂,制备磺化聚醚砜(SPES)。选取磺化度(DS)为14%的SPES溶液,制备PES-SPES共混膜,考察了共混膜的脱盐效果和抗污染性能。结果表明,共混膜的基质材料中,随SPES、PES的质量比的增加,共混膜表面膜孔径增大,断面结构由指状孔向海绵状孔转化,共混膜水通量增加,截留率降低,当SPES的DS为14%、SPES、PES的质量比0.75时,制得共混膜水通量为253.7 L/(m~2·h),对PEG6000、PEG10000和PEG20000的截留率分别为56.8%、74.5%和90.6%;共混膜在相同测试条件下对Na_2SO_4截留效果大于NaCl,经亲水改性的PES-SPES共混膜亲水性提高,抗污染性能明显增强。     

氯化锂对聚醚砜膜过滤性能和污染行为的影响

向聚醚砜(PES)铸膜液中添加无机氯化锂(LiCl)颗粒,通过相转化法制备PES膜,考察LiCl含量对PES膜过滤性能和污染行为的影响,分析污染物过滤堵塞模型.结果表明,LiCl的添加质量分数为5％时,PES膜孔径增大80％,水通量增加了3倍;LiCl并没有削弱PES膜对牛血清蛋白的截留效果,其截留率高达97％.而且,...     

负载纳米银磺化聚醚砜超滤膜的制备及其抗菌性

为了改善聚醚砜(PES)膜的抗污染性能,将PES磺化并制成超滤膜,然后将超滤膜浸渍在硝酸银溶液中,吸附Ag~+的超滤膜在维生素C的还原作用下将Ag负载在膜表面,制备了负载纳米银磺化超滤聚醚砜膜(SPES-Ag)。通过扫描电镜(SEM)、原子力显微镜(AFM)、X射线衍射(XRD)对SPES-Ag超滤膜进行了表征,并通过细胞吸附法进行了抗菌性测试。结果表明,纳米银的平均尺寸为120 nm,它的负载提高了超滤膜的抗菌性能,对大肠杆菌、假单胞菌和金黄色葡萄球菌的抗菌率分别达到了96.7%,98.3%,87.7%。此外,水通量和截留率的测试结果表明,SPES-Ag超滤膜的水通量为438.4 L/(m~2·h),对牛血清蛋白(BSA)的截留率达到94.3%。     

PES中空纤维含哌嗪-氟单体聚酰胺纳滤膜制备及耐氯性能

以聚醚砜(PES)-N,N-二甲基乙酰胺(DMAc)-PEG200为铸膜液体系,制备了PES中空纤维超滤膜,讨论了空气段间距和芯液组成对PES中空纤维超滤膜的影响。选用PESUFB90中空纤维超滤膜为基膜,以0.5%(w/v)哌嗪(PIP)和0.5%(w/v)2,2-二(1-羟基-1-三氟甲基-2,2,2-三氟乙基)-4,4-亚甲基双苯胺(BHTTM)为水相溶液,0.15%(w/v)均苯三甲酰氯(TMC)为油相溶液,采用界面聚合法制备了PES中空纤维复合纳滤膜,利用SEM、AFM和动态接触角等表征了PES基膜和纳滤膜的性能,讨论了操作压力和盐浓度对PES纳滤膜分离性能的影响,测定了纳滤膜的孔径,考察了膜的耐氯性能。结果表明,界面聚合后PES膜的表面粗糙度提高;PES基膜的接触角大于纳滤膜的接触角,纳滤膜亲水性较好;纳滤膜的有效孔径约为0.5 nm;0.6 MPa下,纯水通量为31.2 LMH,对硫酸盐的截留率在90%以上。此外,经1000 ppm Na Cl O处理18 h后,膜通量和截留无明显变化,显示良好的耐氯性能。     

壳聚糖交联苯乙烯马来酸酐/聚醚砜纳滤膜的制备及性能研究

采用相转化法、共混法和交联法,以聚醚砜(PES)、磺化聚砜(SPSF)、聚乙二醇400(PEG400)、苯乙烯马来酸酐(SMA)、N,N-二甲基乙酰胺(DMAc)、壳聚糖(CTS)为原料制备了壳聚糖(CTS)交联苯乙烯马来酸酐(SMA)/聚醚砜纳滤膜。结果表明,交联CTS后,膜表面更加致密,断面结构中微孔增多,指状孔长度延长。当CTS质量分数为25%时,复合膜的综合性能最佳。此时,和SMA/PES基膜相比,CTS/SMA/PES复合纳滤膜的水接触角由94.6°降至69°,纯水通量为10.06 L/(m~2·h),对2 g/L Na_2SO_4溶液的截留率由22.43%提高至98.87%,膜的亲水性和脱盐率等性能得到很大提高。     

PSF/PES共混膜的制备与优化

实验以聚砜(PSF)、聚醚砜(PES)为膜材料,N-甲基吡咯烷酮(NMP)为溶剂,水为凝胶剂,采用L-S相转化法制备了复合膜用共混基膜.按照均匀设计方法优化制膜条件,用SPSS软件处理实验结果得到模型方程,方程反映了各种因素及其交互作用对膜透水性能的影响规律,模型计算值与实验值吻合良好.对于给定的PES含量,随着共混物中PSF /PES 总量的增大,优化计算得到的PVP含量和丙酮含量增大,但相应的膜水通量减小.在上述理论指导下,实验制备基膜的纯水通量为290.6 L·m-2·h-1,对牛白蛋白的截留率达到88.2%.     

聚醚砜超滤膜的制备与优化

为了给复合膜制备提供理想的支撑基膜,采用L-S相转化法制备聚醚砜超滤膜。通过正交实验设计,系统研究了各种因素对聚醚砜超滤膜性能的影响,并采用回归分析得到了模型方程。结果表明:所制备的聚醚砜超滤膜的水通量为246. 9L·m-2·h-1 (操作压力0. 1MPa),该膜对浓度为500mg/L的聚乙烯醇(PVA80 000)截留率达95%以上。     

低截留分子量聚醚砜超滤膜

以聚醚砜(PES)为原料,均苯三甲酸(TMA)为添加剂,采用浸没沉淀相转化法制备聚醚砜超滤基膜,之后将聚乙烯醇(PVA)溶液涂覆在膜表面,经加热交联得到低截留分子量超滤膜。实验结果表明,随着聚乙烯醇浓度升高,截留分子量先减小再增加;随着热处理温度的升高,水通量减少,截留分子量减小。聚乙烯醇质量浓度为0.1%,80℃加热10 min,膜的截留分子量为900,纯水通量为6.10 L/(m~2·h)。红外光谱分析证实PVA与TMA反应生成了交联结构。     

低截留分子量聚醚砜超滤膜

以聚醚砜(PES)为原料，均苯三甲酸(TMA)为添加剂，采用浸没沉淀相转化法制备聚醚砜超滤基膜，之后将聚乙烯醇(PVA)溶液涂覆在膜表面，经加热交联得到低截留分子量超滤膜。实验结果表明，随着聚乙烯醇浓度升高，截留分子量先减小再增加；随着热处理温度的升高，水通量减少，截留分子量减小。聚乙烯醇质量浓度为0.1%，80℃加热10 min，膜的截留分子量为900，纯水通量为6.10 L/(m²·h)。红外光谱分析证实PVA与TMA反应生成了交联结构。     

水中天然有机物对超滤膜污染研究

对超滤膜受天然有机物污染的特性进行研究,同时考查无机矿物质成分对污染的协同影响。采用PES平板膜进行膜污染试验,模拟地表水研究腐殖酸以及钙离子的影响并进行了化学清洗试验。研究结果表明,在pH值为7.8,腐殖酸质量浓度为15 mg/L,操作压力0.1 MPa下,当钙离子浓度为4 mmol/L时,膜污染最为严重,10 min后膜通量降到起始膜通量的60%以下。先用0.1 mol/L的NaOH,再用0.5%的盐酸清洗后,膜通量可恢复至起始膜通量的98%。     

Effects of PEG on Morphology and Permeation Properties of Polyethersulfone Membranes

Abstract

Flat sheet asymmetric polyethersulfone (PES) ultrafiltration (UF) membranes were prepared from a homogenous solution of PES via immersion precipitation in a water coagulation bath. The effect of the solvents (N-methyl-2-pyrrolidone (NMP) and N,N-dimethylformamide (DMF)) in preparation of the casting solution was studied. The effects of the molecular weight of polyethylene glycol (PEG) (400, 1500, and 6000 Da) on the morphology and the permeation properties of PES membranes were also investigated. Surface and cross-sectional morphology of the prepared membranes were studied by Scanning electron microscopy (SEM). The permeation performance of the prepared membranes was evaluated in terms of pure water flux (J_w), water content, porosity, hydraulic permeability, protein solution flux, and protein rejection. A solution of human serum albumin (HSA, Mw = 66,000 Da) was used as feed to study the permeation properties of the prepared membranes. Increasing molecular weight of PEG additives from 400 to 6000 Da enhances pure water permeation flux and HSA solution permeation flux while it reduces the protein rejection.     

聚乙烯吡咯烷酮对聚醚砜膜结构和性能的影响

以聚醚砜为膜材料,聚乙烯吡咯烷酮（PVP）为添加剂,N,N-二甲基乙酰胺为溶剂,采用相转化法制备了聚醚砜超滤膜。通过制膜液粘度、膜的孔隙率、表面接触角、机械性能以及对牛血清蛋白分离性能的测试和扫描电镜（SEM）对膜孔结构的观察,研究了PVP的添加量对聚醚砜制膜液粘度及其膜结构和性能的影响。结果表明,PVP的添加提高了膜的亲水性和制膜液的粘度,但膜的抗拉强度有所降低;膜的水通量随着PVP含量的增加先升高后降低,在5%时最大水通量是508.33L/（m^2·h）,而此时牛蛋白截留率最小为66.27%;SEM观察的结果是膜的断面上部形成指状孔结构,下部形成海绵状孔结构,当PVP含量为5%时膜有斜指状孔结构,且指状孔也逐渐延伸到膜的底部,其壁为稀疏的海绵状孔结构。     

二氧化硅填充聚醚砜超滤膜

本文通过在聚醚砜中引入活性炭粉和无定型二氧化硅粒子，以N，N-二甲基甲酰胺为溶剂，以水为凝固浴，利用相转化湿法成膜机理，制得了一系列不同粒子含量的聚醚砜超滤平板膜。通过扫描电子显微镜对膜结构进行了观察和对比研究，并对膜的纯水通量和鸡蛋卵清蛋白的截留进行了测试，结果发现：二氧化硅的加入，改变了铸膜液的浊点组成；产生了大量的界面空隙，即界面孔：增加了膜孔的贯通性；提高了膜的亲水性；使膜的通量大大提高，并且保持了很好的截留率。而活性炭粉填充聚醚砜超滤膜的综合性能远远差于二氧化硅填充聚醚砜超滤膜。     

Development of novel surface modified phase inversion membranes having hydrophobic surface-modifying macromolecule (nSMM) for vacuum membrane distillation

Eleven PES membranes, into which newly synthesized surface-modifying macromolecule (nSMM) was incorporated, were prepared by using the ‘phase inversion technique’ with different preparation conditions to find the effects of membrane casting parameters on the characteristics and performances of the surface modified PES membranes. The membranes so prepared were characterized by solute separation data from ultrafiltration experiments. The results showed that the mean pore size as well as the surface hydrophobicity increased with an increase in evaporation time for the casting solution blended with nSMM (without PVP). When PVP was added into the casting solution, the mean pore size as well as the contact angle decreased while the pure water permeation flux increased. The surface hydrophobicity decreased with an increase in gelation bath temperature.Four membranes were further prepared and subjected to vacuum membrane distillation (VMD). They were characterized by different analytical instruments and pure water permeation test before being used to VMD. The results showed that a distinctive surface layer was formed in nSMM blended PES membranes. It was also found that nSMM blended PES membranes were sufficiently hydrophobic and porous to be used for the separation of an ethanol/water mixture.     

PAN-g-SiO_2聚合物的制备及PAN-g-SiO_2/PES超滤膜亲水性研究

通过纳米SiO2颗粒表面的-OH在硝酸铈铵作用下形成自由基引发聚丙烯腈(PAN)水解后在其分子主链上产生成的-C=C-进行自由基接枝反应,制备了不同粒径纳米SiO2接枝丙烯腈聚合物(PAN-g-SiO),IR2和EDS分析表明纳米SiO2接枝在PAN分子链上。进一步研究了PAN-g-SiO2对PES超滤膜亲水性的影响。静态接触角实验和纯水通量实验结果表明,PAN-g-SiO2聚合物的加入明显地降低了PES超滤膜的亲水角,提高了水通量。     

Polyethersulfone-polyvinylpyrrolidone composite membranes:Effects of polyvinylpyrrolidone content and polydopamine coating on membrane morphology,structure and performances

Hydrophilic modification is a promising method to inhibit fouling formation on ultrafiltration membrane.In this work,different mass concentrations (1％-16％) of hydrophilic polyvinylpyrrolidone were incorpo-rated into polyethersulfone (PES) membranes fabricated by none-solvent induced phase separation.Then,polydopamine (PDA) coating on the surface of prepared membrane was carried out at pH 8.5.The mor-phology and structure,surface hydrophilicity,permeation flux,BSA rejection,antifouling and stability performances of PES and PDA/PES modified membranes were investigated in detail.The results indicated that PDA was successfully attached onto the membranes.Membrane hydrophilicity was evaluated by water contact angle measurement.The contact angles of modified membranes reduced remarkably,sug-gesting that the membrane hydrophilicities were significantly increased.The results of filtration tests,which were done by dead-end filtration of bovine serum albumin solution,showed that the properties of permeability and fouling resistance were obviously improved by PDA modification.When polyvinylpyrrolidone mass content reached 10％,flux recovery ratio of modified membrane was up to 91.23％,and its BSA rejection were over 70％.The results of stability tests showed that the modified mem-branes had good mechanical stability and chemical stability.This facile fabrication procedure and out-standing performances suggested that the modified membranes had a potential in treating fouling.     

Hydrophobic polyethersulfone porous membranes for membrane distillation

Membrane distillation (MD) is a thermal, vapor-driven transportation process through micro porous hydrophobic membranes that is increasingly being applied to seawater and brine desalination processes. Two types of hydrophobic microporous polyethersulfone flat sheet membranes, namely, annealed polyethersulfone and a polyethersulfone/tetraethoxysilane (PES/TEOS) blend were prepared by a phase inversion process. The membranes were characterized and their performances were investigated using the vacuum membrane distillation of an aqueous NaCl solution. The performances of the prepared membranes were also compared with two commercially available hydrophobic membranes, polytetrafluorethylene and polyvinylidene fluoride. The influence of operational parameters such as feed temperature (25–65 °C), permeate vacuum pressure (200–800 mbar), feed flow rate (8–22 mL/s) and feed salt concentration (3000 to 35000 mg/L) on the MD permeation flux were investigated for the four membranes. The hydrophobic PES/TEOS membrane had the highest salt rejection (99.7%) and permeate flux (86 kg/m²·h) at 65 °C, with a feed of 7000 ppm and a pressure of 200 mbar.     

Effects of coagulation bath temperature and polyvinylpyrrolidone content on flat sheet asymmetric polyethersulfone membranes

In this study, effects of coagulation bath temperature (CBT) and polyvinylpyrrolidone (PVP K15) concentration as a pore former hydrophilic additive on morphology and performance of asymmetric polyethersulfone (PES) membranes were investigated. The membranes were prepared from a PES/ethanol/NMP system via phase inversion induced by immersion precipitation in a water coagulation bath. The morphology of prepared membranes was studied by scanning electron microscopy (SEM), contact angle measurements, and mechanical property measurements. Permeation performance of the prepared membranes was studied by separation experiments using pure water and bovine serum albumin (BSA) solution as feed. The obtained results indicate that addition of PVP in the casting solution enhances pure water permeation flux and BSA solution permeation flux while reducing protein rejection. Increasing CBT results in macrovoid formation in the membrane structure and increases the membrane permeability and decreases the protein rejection. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Surface and pore modification of tripolyphosphate-crosslinked chitosan/polyethersulfone composite nanofiltration membrane; characterization and performance evaluation

A PES-based composite nanofiltration membrane was prepared by spreading a thin layer of sodium tripolyphosphate (STPP)-modified chitosan (CS) on a PES membrane. Two approaches of modification were employed: coating, and injecting the chitosan solution into PES membrane by applying pressure. Physicochemical properties of the prepared membranes were characterized by FTIR-ATR, zeta potential, contact angle, AFM and FE-SEM methods. AFM images showed a denser and more compact surface for STPP-modified membranes compared to the unmodified one. The membranes prepared by the second approach illustrated favorable properties: the increase of both flux and rejection. Engaging of -NH₂ groups in CS with polyanionic phosphate groups of STPP resulted in less availability of functional groups. Furthermore, denser and relatively higher positively charged surface could be the main reasons for higher rejection of membrane composed of 0.05wt% STTP towards copper ions in comparison with the other membranes. Furthermore, the presence of SO ₄ ^2- ions in the CuSO₄ solution slightly changed the positive charge of the membrane surface, resulting in tangible variations in rejection. According to the Donnan exclusion theory, relative increase of the negative charge of the surface in the presence of the highest concentration of STTP caused less NaCl and CuSO₄ rejection compared to the other STPP modified membranes.