聚乙二醇600和草酸对中空纤维超滤膜结构和性能的影响

通过考察添加剂PEG600和草酸对杂萘联苯聚醚砜酮（PPESK）中空纤维超滤膜结构和分离性能的影响，发现：PEG600的加入不会改变膜的内部结构，均为指状结构，随着PEG600浓度的增加，膜致密层厚度逐渐增加。膜的水通量和截留率随有机添加剩PEG600的浓度变化规律性不强。随小分子添加剂草酸浓度的提高，膜结构逐渐由指状结构转变成海绵状结构，PPESK中空纤维超滤膜的纯水通量逐渐上升，截留率呈波浪形变化。比较不同凝胶浴温度下的膜分离性能可以看到，凝胶浴温度提高可以显著提升膜的纯水通量。     

聚砜中空纤维超滤膜制备及性能

以聚砜(PSU)为成膜聚合物,聚乙烯吡咯烷酮(PVP)为成孔添加剂,二甲基乙酰胺为溶剂,采用干–湿法纺丝工艺和浸没沉淀相转化法制备了PSU中空纤维膜,研究了添加剂含量、凝固浴温度、干纺程对中空纤维膜结构与性能的影响。结果表明,随着添加剂PVP含量的增大,在PSU中空纤维膜表皮层形成贯通膜孔,皮层变薄,孔径变大,指状孔发达,水通量提高,截留率下降;凝固浴温度升高对膜水通量起到一定的抑制作用,凝固浴温度为30℃时,制得的膜具有较高的水通量和卵清蛋白截留率,以及较高的孔隙率;干纺程的大小对膜性能有重要影响,当干纺程为11 cm时,膜纯水通量为200 L/(m~2·h),截留率为90%,综合性能较好。     

聚砜纳滤膜的制备

研究聚砜纳滤平板膜的制备,通过浸没相转化过程制备膜,讨论和研究聚砜(PSF)含量,聚乙烯吡咯烷酮含量,凝固浴温度和空气浴时间对膜结构、硫酸镁溶液水通量和截留率的影响,结果表明;聚砜(PSF)含量增加,凝固浴温度升高、空气浴时间增长时,都可以使膜水通量降低,截留增大,而聚乙烯吡咯烷酮(PVP)含量增加时水通量增加,截留率降低。     

聚砜管式超滤膜的制备及其结构性能研究

采用浸没相沉淀法制备聚砜(PSF)管式超滤膜。以纯水通量、卵清蛋白截留率、扫描电镜表征膜的结构和性能,考察了PSF含量、凝固浴温度和组成、添加剂种类和含量对PSF管式膜成膜性能及结构的影响。结果表明,凝固浴温度升高、聚乙烯吡咯烷酮(PVP)含量增加、PEG-400含量增加,都可以使膜的水通量增加、截留率降低;而凝固浴中添加溶剂二甲基乙酰胺(DMAc)、铸膜液中PSF含量的增加,都可以使膜的通量减小,截留率升高。     

凝胶相转化温度和空气预蒸发时间对PVDF超滤膜性能及结构的影响

利用非溶剂相转化法(NIPS),以聚偏氟乙烯(PVDF)/聚乙烯吡咯烷酮(PVP)/N,N-二甲基乙酰胺( DMAC)为铸膜液体系,水为凝固浴制备了大通量超滤膜.考察了铸膜液温度、凝胶浴温度、空气预蒸发时间等条件对超滤膜性能与结构的影响.研究结果显示,随着铸膜液和凝胶浴温度的提高,膜纯水通量增大,强度增强,截留率降低,膜的第一泡点压力减小,膜的孔隙率随铸膜液温度升高而增大,随凝胶浴温度升高先增大后减小,膜断面指状孔发育较为通透,海绵层致密.延长铸膜液在空气预蒸发时间,膜的第一泡点压力和孔隙率降低,超滤膜截留率提高,通量和强度变化不大.     

新型聚芳醚腈酮中空纤维超滤膜的研究

以含二氮杂萘酮结构聚芳醚腈酮(PPENK)为膜材料,N-甲基-2-吡咯烷酮(NMP)为溶剂,采用干-湿相转化法制备了中空纤维超滤膜.考察了聚合物浓度、添加剂含量以及纺丝过程中空气间隙、凝胶浴温度和纤维壁厚对膜结构及性能的影响.结果表明,当聚合物浓度为13%,添加剂EgOH含量α=0.9时,膜通量可达770 L·m-2·h-1,对BSA的截留率在90%以上;增大空气间隙可使膜的截留性能提高,但膜通量有所下降,最佳空气间隙为5～8cm;凝胶浴温度的升高增大了膜的通量,截留率下降幅度不大,凝胶浴温度宜控制在21～25℃范围内;纤维壁厚在0.15～0.18 mm时膜性能最佳.     

凝胶浴条件对PVDF/CaCO3共混中空纤维膜性能和结构的影响

采用干-湿相转化法制备了PVDF/CaCO3共混中空纤维膜,考察了芯液组成和外凝胶浴温度对共混膜结构和性能的影响。结果表明,随芯液中酸含量增加,膜纯水通量迅速升高,BSA截留率略有下降;膜拉伸强度下降,断裂伸长率增加。SEM图显示,膜断面指状孔的数量增多、支撑层厚度变薄、膜亚层海绵孔增加;相应孔隙率升高,而泡点压力略微下降。当外凝胶浴温度较高时,膜支撑层和外皮层较为致密,导致膜纯水通量明显下降,同时BSA截留率在80℃高温外凝胶浴时,由于膜外皮层上出现少量大孔结构,而迅速下降为62.55%。     

低截留分子质量新型聚芳醚腈酮超滤膜的研制

以新型聚芳醚腈酮为膜材料 ,以N -甲基 - 2 -吡咯烷酮 (NMP)为溶剂 ,研究了聚合物浓度、添加剂种类及含量、凝胶浴温度等对超滤膜性能的影响。结果表明 ,聚合物质量分数以 1 2 %～ 1 3 %为合适的制膜浓度 ,以聚乙二醇PEG - 4 0 0为添加剂时获得了高截留率和高水通量的超滤膜。随着凝胶浴温度的升高 ,水通量明显增大 ,而截留率有所下降 ,而共聚物的浓度增加则有相反的效果。制得的超滤膜具有较低的截留分子量 (PEG- 2 0 0 0 ) ,将制得的超滤膜用于达旦黄、黄X-G等染料的分离 ,截留率均达 90 %以上     

七通道中空纤维超滤膜的制备与性能调控

以聚醚酰亚胺(PEI)为膜材料、N,N-二甲基乙酰胺为溶剂、水为凝固浴,采用干-湿相转化法制备七通道中空纤维超滤膜,研究了PEI含量和3种添加剂γ-丁内酯、聚乙二醇600(PEG600)、聚乙烯吡咯烷酮-K30对膜结构和性能的影响。结果表明,随着PEI含量升高,膜断面由指状孔向海绵状孔转化,拉断力和爆破压力大幅提升。以PEG600为添加剂时膜具有最佳的综合性能,拉断力为16.55 N,纯水通量为247.39 L/(m~2·h),对牛血清白蛋白的截留率达93.9%。     

聚丙烯腈超滤膜的制备

为了得到高性能的超滤膜,采用相转化法,以聚丙烯腈(PAN)为原料,N-甲基-吡咯烷酮(NMP)为溶剂,制备了聚丙烯腈超滤膜.采用纯水通量以及膜对牛血清蛋白(BSA)的截留率作为评价标准,并使用扫描电镜对膜结构进行表征.研究了聚合物质量分数、添加剂种类、凝胶浴温度、凝胶浴种类对膜性能的影响.研究发现:在一定范围内提高聚合...     

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     

Preparation and characterization of PES/CA microporous membranes via reverse thermally induced phase separation process

The blend polyethersulfone (PES)/cellulose acetate (CA) flat‐sheet microporous membranes were prepared by reverse thermally induced phase separation (RTIPS) process. The effects of CA content and coagulation bath temperature on membrane structures and properties were investigated in terms of membrane morphology, water contact angle, permeation performance, and mechanical properties. The cloud point results indicated that the cloud point decreased with the increasing content of CA. When the coagulation bath temperature was lower than the cloud point, the membrane formation process underwent nonsolvent induced phase separation (NIPS) process and dense skin layer and finger‐like structure were formed in membranes. These membranes had lower pure water flux and poor mechanical properties. But when the coagulation bath temperature was higher than the cloud point, the membrane formation process underwent RTIPS process. The porous top surface as well as porous cross‐section of the membranes were formed. Therefore, high pure water flux and good mechanical properties were obtained. The contact angles results indicated that the hydrophilicity of the prepared membranes improved obviously with the addition of CA. When the content of CA was 0.5 wt% and the membrane formation temperature was 323K, the PES/CA microporous membrane which was prepared via the RTIPS process displayed a optimal permeability of the pure water flux of 816 L m^?2 h^?1 and the BSA rejection rate of 49.5%, which showed an increase of 48.9% and 23.6% than that of pure PES membrane, respectively. Moreover, the mechanical strengths of the membranes obtained by RTIPS process were better than those membranes prepared by NIPS process. POLYM. ENG. SCI., 58:180–191, 2018. © 2017 Society of Plastics Engineers     

Fabrication and characterization of maleic anhydride grafted polypropylene membranes with high antifouling properties

In this study, maleic anhydride grafted polypropylene microporous flat‐sheet membranes were prepared via a thermally induced phase separation method with a mixture of dibutyl phthalate and dioctyl phthalate as a diluent. The effects of the polymer composition and coagulation bath temperature on the morphology and performance of the fabricated membranes were investigated. The hydrophilicity results of the membranes demonstrated that membrane modification reduced the water contact angle by about 45°, whereas the pure water flux was enhanced about four times. The antifouling behavior of the fabricated membranes was also investigated in a membrane bioreactor. The results show that the pure water flux, membrane pore size, and porosity decreased, whereas the antifouling performance was improved with increasing polymer concentration and decreasing bath temperature. Finally, the results reveal that the removal efficiency of contaminates was independent on the membrane characterization and was done exclusively through biological removal. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43857.     

Synthesis and characterization of polyethersulfone membranes

Phase inversion method was used to prepare polyethersulfone (PES) ultrafiltration (UF) membranes. Polyethylene glycol (PEG); N, N-dimethyl formamide (DMF) and water were utilized as pore-forming additive, solvent and non-solvent, respectively. Effects of PES and PEG concentrations in the casting solution, PEG molecular weight (MW) and coagulation bath temperature (CBT) on morphology of the prepared membranes were investigated. Taguchi experimental design was applied to run a minimum number of experiments. 18 membranes were synthesized and their permeation and rejection properties to pure water and human serum albumin (HSA) solution were studied. It was found out that increasing PEG concentration, PEG MW and CBT, accelerates diffusional exchange rate of solvent (DMF) and non-solvent (water) and consequently facilitates formation of macrovoids in the membrane structure. The results showed that, increasing PES concentration, however, slows down the demixing process. This prevents instantaneous growth of nucleuses in the membrane structure. Hence, a large number of small nucleuses are created and distributed throughout the polymer film and denser membranes are synthesized. A trade-off between water permeation and HSA rejection was involved, with membranes having higher water permeation exhibited lower HSA rejection, and vice versa. Hence, optimizing preparation variables to achieve high pure water permeation flux along with reasonable HSA rejection was inevitable. Analysis of variance (ANOVA) showed that all parameters have significant effects on the response (water flux and HSA rejection). However, CBT and PES concentration were more influential factors than PEG concentration and MW on the responses.     

溶剂对水处理用PVDF微孔膜结构性能影响

利用N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAc)、磷酸三乙酯(TEP)和二甲基亚砜(DMSO)4种溶剂制备PVDF微孔膜,考察溶剂对成膜性能的影响,除了测试膜结构、孔隙率、清水通量等常规指标外,增加膜污染速率指标,研究4种溶剂成膜在实际膜-生物反应器(MBR)内的运行情况,得到4种溶剂成膜结构不同,具有贯穿性指状孔的DMSO溶剂成膜具有最高的孔隙率,高清水通量,并在MBR内表现出最低的污染速率,最适于制备水处理用的PVDF膜;具有海绵状孔的TEP溶剂成膜具有最高的清水通量,高的孔隙率,在MBR内污染速率较低;DMF、DMAc溶剂成膜结构类似,具有不贯穿的指状孔,孔隙率及清水通量均较低,膜污染速率高,不适于水处理MBR用膜。     

添加剂对聚砜膜结构和性能的影响

通过浸没沉淀相转化法制备聚砜超滤膜,分别以高分子聚乙烯基吡咯烷酮（PVP-K30,PVP-K90）、聚乙二醇（PEG-6000,PEG-20000）和小分子氯化锌（ZnCl2）、丙酸（AS）6种物质作为制备聚砜超滤膜的添加剂,含量均为10%。并对聚砜超滤膜的断面结构、纯水通量、牛血清蛋白（BSA）截留率、孔隙率及平衡水含量等5项性能进行了测试及表征。由断面结构可以看出,PVP-K90作为添加剂时,制得膜的断面完全为海绵状结构,其它添加剂制得膜断面中均有指状孔结构;PVP-K30作为添加剂时制得膜的纯水通量最大;丙酸作为添加剂制得膜的BSA截留率最高;聚乙烯基吡咯烷酮（PVP）和聚乙二醇（PEG）制得膜的平衡水含量及总孔隙率均较高,但闭孔也较多。     

Intensification and optimization of the characteristics of polyacrylonitrile nanofiltration membranes with improved performance through experimental design and statistical analysis

The present study aims to employ experimental design and statistical analysis in order to investigate in detail the effect of various prominent parameters on the characteristics and performance of polyacrylonitrile nanofiltration membranes for the treatment of electroplating wastewaters targeting Ni, Cr, and Zn ions. Incorporation of TiO₂ into the membrane matrix was effective in improving pure water flux (PWF) by ~16%. Also, PWF and Ni rejection of membranes escalated to 118.55 L m⁻² h⁻¹ and 90.79%, respectively upon addition of 1.5 wt% citric acid to the dope. Variation in coagulation bath temperature from 25°C to 45°C led to the formation of membranes having higher porosity with enhanced PWF by about 25% at the expense of only 5% reduction in Ni rejection. Parameters were optimized by analysis of variance (ANOVA). In contrast to the effect of feed concentration, an increase in feed pressure and pH enhanced permeate flux and total ion rejection. Similarly, permeate flux increased at higher operational temperatures without change in total rejection. A mathematical model was developed by applying ANOVA and the best combination of operating parameters was obtained by optimization.     

Improvement of permeation performance of polyethersulfone (PES) ultrafiltration membranes via addition of Tween‐20

In this study, effects of Tween‐20 (polyoxyethylene sorbitan monolaurate) as a variable surfactant additive on morphology, permeation performance and antifouling properties of asymmetric polyethersulfone (PES) membranes were investigated. The membranes prepared from PES/polyethylene glycol (PEG)/N,N‐dimethylformamide (DMF) system via phase inversion induced by immersion precipitation in water coagulation bath. The membranes performances were evaluated using ultrafiltration (UF) experiments. The scanning electron microscope and atomic force microscopy analysis were performed to investigate the membrane morphology. The obtained results indicate that by increasing the concentration of Tween‐20, the membrane morphology changes slowly from thin finger‐like structure with spongy structure to long and wide finger‐like structure with some macrovoids. Addition of surfactant to the casting solution increases the porosity of the membrane sublayer. It was found out that the rejection ratio of Bovine serum albumin (BSA) decreases, while the flux recovery ratio remarkably increases and the degree of irreversible fouling decreases. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

碳纳米管-聚偏氟乙烯共混超滤膜的制备及性能研究

采用硫酸、硝酸混酸改性多壁碳纳米管(MWNTs),将改性的MWNTs分散于1-甲基-2-吡咯烷酮(NMP)中,再与聚偏氟乙烯(PVDF)的NMP溶液混合,采用浸没相转化法制备MWNTs-PVDF复合超滤膜,考察了制膜条件对膜结构和性能的影响。结果表明,当铸膜液中MWNTs的质量分数到达0.09%、凝胶浴温度达到30℃时,纯水通量最大;随着预蒸发时间的延长,纯水通量下降;铸膜液溶解温度在40～80℃时,所制膜的纯水通量也随溶解温度的升高而增加。