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铸膜液中水含量对聚砜超滤膜结构和性能的影响 总被引:1,自引:0,他引:1
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. 相似文献
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PVC/PMMA合金微滤膜的研制 总被引:5,自引:1,他引:4
以PVC/PMMA合金为膜材料 ,研制出了具有非对称断面结构的微滤膜。经优化后膜的平均孔径为 0 .18-9.2 8μm ,在 0 .1MPa操作压力下膜的纯水通量可高达 2 2 0 0 0L/m2 ·h。对影响膜结构与性能的若干因素也进行了探讨。 相似文献
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研究了浸没沉淀相转化法制备聚偏氟乙烯(PVDF)微滤膜过程中挥发时间、凝胶浴温度、铸膜厚度和铸膜速度对成膜的形态结构、孔隙率、过滤性能以及污染性能的影响。结果表明,随挥发时间延长,成膜孔隙率变小,纯水通量先增加后减小,以10 s为挥发时间制得的膜抗污染性能最强;随凝胶浴温度的升高,孔隙率、纯水通量及抗污染性能先增大后减小,在45℃成膜污染速率最低;随铸膜厚度的增加,纯水通量逐渐减小,孔隙率呈现先增加后减小的规律,且铸膜厚度为0.25 mm时成膜抗污染性能最好。 相似文献
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《水处理技术》2017,(9)
探讨了聚乙二醇(PEG)及其分子量对氯化聚氯乙烯(CPVC)铸膜液黏度及其超滤膜微观结构和性能(纯水通量、截留率、机械性能和耐污染性能)的影响。结果表明,随着PEG分子量的增大,CPVC铸膜液黏度增大,CPVC超滤膜表面由网络大孔结构变为致密结构,PEG400和600对CPVC超滤膜断面微观结构没有太大影响,仍然保持海绵状结构,PEG相对分子质量超过1 000以后,CPVC超滤膜断面变为指状大孔结构与皮层构成非对称结构。铸膜液中添加PEG后,CPVC超滤膜纯水通量大幅度上升,但是截留率有不同程度的下降;随着PEG分子量的增大,CPVC超滤膜的纯水通量,耐污染性能及截留率均呈上升趋势。综合比较,PEG600作为添加剂,CPVC超滤膜能获得较好的性能。 相似文献
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研究了亲水性聚偏氟乙烯(PVDF)微滤膜的结构、过滤性能、亲水性和清水反冲洗效果。膜结构由SEM照片和泡点-流速法测定的膜孔径分布表征,通过过滤双蒸水和BSA缓冲液来表征膜的通量、过滤衰减和清洗恢复性能,并对BSA液过滤前后膜结构进行了对比分析,膜亲水性由水接触角表征。试验结果表明,膜孔径分布范围在0.22~0.27μm之间;初始静态水接触角为61.5°,水滴在80 s内渗入膜中;膜初始水通量为1 651.0 L.m-2.h-1,过滤浓度1 g.L-1pH=7.0的BSA液时膜通量随着过滤时间的延长而不断减小,最后达到一稳定的平衡通量229.3 L.m-2.h-1;平均过滤阻力构成分别为:Rp占70.0%,Rm占19.5%,Ri占7.3%,Re占3.1%;污染膜可通过清水反冲洗来恢复,4次循环后膜通量可恢复至1 008.9 L.m-2.h-1,膜通量恢复率达到61.1%。 相似文献
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《Gas Separation & Purification》1991,5(4):215-221
The mean pore size and surface porosity of the dense skin of polymeric asymmetric membranes were determined by the gas permeability method. When the contribution of the flux of a gas permeating through the dense skin is greater than 10% of the ‘slip’ flux in the pore, the dense skin thickness can be obtained from the equations developed in the present work. The method was applied to investigate the influence of the parameters involved in the preparation of polysulphone asymmetric membranes by the wet process of phase inversion. Electron microscopy was used to determine the structure and thickness of the dense skin. The results obtained with the microporous membranes synthesized indicate the following trends: pore size increases and surface porosity decreases with (i) increasing temperature of the coagulation bath; (ii) increasing concentration of polymer in the casting solution; and (iii) increasing casting thickness. 相似文献
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Several kinds of chloromethyl polysulfones (CMPSF) with different chlorinity and reactive groups were synthesized by Friedel‐Crafts reaction, which could be utilized as reactively matrix membrane materials. The CMPSF hollow matrix membranes were prepared with phase inversion by utilization of the CMPSF/additive/DMAC casting solution and CMPSF as membrane materials. The rheological behavior of CMPSF/additives/DMAC spinning casting solution was studied. The experimental results showed that the spinning casting solution was a pseudoplastic fluid, the apparent viscosity of the spinning casting solution decreased with the increase of shearing rate, and the viscous flow activity energy of the spinning casting solution was inclined to unchange at high shearing rate. The effects of composition of spinning casting solution and process parameters of dry–wet spinning on the structure of CMPSF hollow fiber matrix membrane were investigated. The pore size, porosity, and water flux of membrane decreased with the increase of additive content, bore liquid, and dry spinning distance. With the increase of extrusion volume outflow, the external diameter, wall thickness, and porosity of the hollow fiber matrix membrane increased, but the pore size and water flux of the membrane decreased. It was also found that the effects of internal coagulant composition and external coagulant composition on the structure of CMPSF hollow fiber matrix membrane were different. The experimental results showed that thermal drawing could increase the mechanical properties of CMPSF hollow fiber matrix membrane and decrease the pore size, porosity, and water flux of the CMPSF hollow fiber matrix membrane, and the thermal treatment could increase the homogeneity and stability of the structure of the CMPSF hollow fiber matrix membrane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 758–771, 2006 相似文献
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Palsamy Kanagaraj Sivasubramaniyan Neelakandan Alagumalai Nagendran 《Korean Journal of Chemical Engineering》2014,31(6):1057-1064
A charged surface modifying macromolecule (cSMM) was synthesized, characterized by FT-IR spectroscopy and blended into the casting solution of cellulose acetate (CA) to prepare surface modified UF membranes by phase inversion technique. With an increasing cSMM additive content from 1 to 4 wt%, pure water flux (PWF) and water content (WC) were increases whereas the hydraulic resistance decreases. Surface characteristic study reveals that the surface hydrophilicity increased in cSMM modified CA membranes. The pore size and surface porosity of the 4 wt% cSMM blend CA membranes increases to 41.26 Å and 0.015%, respectively. Similarly, the molecular weight cut-off (MWCO) of the membranes ranged from 20 to 45 kDa, depending on the various compositions of the prepared membranes. Lower flux decline rate (47.2%) and higher flux recovery ratio (FRR) (89.0%), exhibited by 4 wt% cSMM blend membranes demonstrated its fouling resistant characteristic compared to pristine CA membrane. 相似文献
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《分离科学与技术》2012,47(13):1689-1704
Abstract The functions of additives in cellulose acetate butyrate (CAB) membrane casting solution, effect of thermal shrinkage treatment on porous CAB membranes, and the changes of CAB membrane surface morphology during the solvent evaporation step have been investigated. Additives (glycerol and lactic acid) in CAB membrane casting solution function only as pore number promoting agents when used at low concentration and function both as pore number and pore size promoting agents when used at higher concentrations. Triethyl phosphate in CAB membrane casting solution functions both as a pore number promoting agent and as a secondary solvent for CAB. Three distinct phases can be observed in the solvent evaporation step in making CAB membranes. With the increase in solvent evaporation time, the number of pores in the first pore size distribution increases in the initial small pore-forming phase and decreases in the large pore-forming phase, and the number of pores in the second pore size distribution always increases with solvent evaporation time. These changes in pore numbers, pore sizes, and pore number ratio in two pore size distributions as well as the membrane skin layer thickness together govern the ultimate membrane performance and result in a maximum solute separation which, in the case of CAB/ acetone membranes, falls at 60 seconds of solvent evaporation time. Significant improvement of the performance of a porous CAB membrane can be achieved by thermal shrinkage treatment. Equally high CAB membrane performance can also be achieved by using a lower concentration of additives in the membrane casting solution. 相似文献
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Ming Tan Gaohong He Yan Dai Rujie Wang Wenhua Shi 《Frontiers of Chemical Science and Engineering》2014,8(3):312-319
The ternary phase diagrams of polyetherimide (PEI)/N,N-dimethylacetamide (DMAc) with H2O and BuOH as non-solvent were simulated using solubility parameter and Flory-Huggins theory. The phase diagrams show that 5.5% H2O/BuOH system containing 5% BuOH and 0.5% H2O, or 6.5% H2O/BuOH system containing 6.2% BuOH and 0.3% H2O is required to induce liquid-liquid demixing for 20 wt-% PEI/DMAc casting solution. Therefore, BuOH can enhance the phase separation of the PEI casting solution and hereby induce higher porosity of the membrane, and the diffusion of BuOH into the water coagulation bath causes larger pore size easily compared with DMAc. Our predictions that the membrane pure water flux first increases then decreases, and the rejection ratio of bovine serum albumin decreases with the increasing concentration of BuOH were validated by the experiments using the prepared membranes. 相似文献
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Reza Peighami Mohamadreza Mehrnia Fatemeh Yazdian Mozhgan Sheikhpour Hamid Esmaeili 《Journal of Polymer Research》2017,24(2):24
Polyethersulfone (PES) is one of the most common polymers used to manufacture membranes. This work focuses on introducing and developing a novel polymer-based membrane applicable in the bio-artificial pancreas. The novel membrane based on the mixture of PES and Pyrolytic carbon (PyC) was studied and compared to PES as a reference. The PES/PyC blend membranes were characterized by top surface SEM, cross section SEM, AFM, contact angle pure water flux, insulin rejection, rejection of immune cells and molecules, and insulin diffusivity performance. In addition, the porosity of the membranes, mean pore size and mean pore density were also measured. The AFM and SEM images indicate that addition of synthesized PyC in the casting solution results in a membrane with high surface and sub-layer porosity and the addition 0.1 wt.% PyC to the casting solution reduced the surface roughness from 22.4 nm to 4.8 nm. The contact angle measurements reveal that the hydrophobicity of pure PES membrane enhanced with increasing the PyC concentration in the casting solution. With the increase of PyC from 0.0 wt.% to 0.1 wt.% in the casting solution, pure water flux reduces from 184 to 153 (L/m2h), insulin rejection reduces from 12 to 9.3%, rejection of immune cells and molecules reduce from 91.8 to 83% and insulin diffusivity increased from1.22E-8 to 1.46E-8. Furthermore, the resulting numbers for the mean pore size, mean pore density, and porosity of the PES-PyC(0.1 wt.%) membrane indicate a considerable improvement compared to pure PES membrane with increasing from 5.5 nm to 7 nm, 26 to 43 pores/area (area stand for the size of membrane surface in which pores were counted), and 68.3% to 84.6%, respectively. At the end, the statistical analysis was performed. 相似文献
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以聚间苯二甲酰间苯二胺(PMIA)为制膜原料,氯化锂(LiCl)、聚乙二醇(PEG-400)和聚乙烯吡咯烷酮(PVP)为添加剂,通过非溶剂诱导相转化法制备了PMIA平板膜,系统考察了聚合物浓度、添加剂种类和含量对PMIA膜结构和性能的影响。结果表明,聚合物浓度和LiCl含量增加,铸膜液黏度增大,导致膜孔径减小,纯水通量降低。而PEG含量的增加,使得聚合物链呈现舒展状态,膜孔径增大,纯水通量升高,亲水性增强。随着PVP含量的增加,膜的纯水通量先升高后降低,膜的亲水性变差。当PMIA的质量分数为9%,LiCl的质量分数为2.8%,PVP的质量分数为1.2%时,膜的纯水通量高达1421.55 L·m-2·h-1·bar-1,对牛血清蛋白(BSA)的截留率为80%,展现出较高的渗透性,为制备高性能膜材料提供了新的思路。 相似文献
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以聚间苯二甲酰间苯二胺(PMIA)为制膜原料,氯化锂(LiCl)、聚乙二醇(PEG-400)和聚乙烯吡咯烷酮(PVP)为添加剂,通过非溶剂诱导相转化法制备了PMIA平板膜,系统考察了聚合物浓度、添加剂种类和含量对PMIA膜结构和性能的影响。结果表明,聚合物浓度和LiCl含量增加,铸膜液黏度增大,导致膜孔径减小,纯水通量降低。而PEG含量的增加,使得聚合物链呈现舒展状态,膜孔径增大,纯水通量升高,亲水性增强。随着PVP含量的增加,膜的纯水通量先升高后降低,膜的亲水性变差。当PMIA的质量分数为9%,LiCl的质量分数为2.8%,PVP的质量分数为1.2%时,膜的纯水通量高达1421.55 L·m-2·h-1·bar-1,对牛血清蛋白(BSA)的截留率为80%,展现出较高的渗透性,为制备高性能膜材料提供了新的思路。 相似文献
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本文就复合中空纤维超滤膜的制备工艺和成膜条件对膜性能影响进行了系统的研究,实验表明,对外压式中空纤维膜,内凝固液条件的改变,主要影响复合膜的内致密层,进而影响膜的透过通量,但对膜的截留孔径无影响,随空中行走距离增大,膜的透过通量减小,截留孔径增大。另外,通过基膜的选定与内凝固液的调节,复合中空纤维膜的分离孔径主要取决于复合层膜,即在适宜的条件下,基膜不影响复合膜的分离孔径,同时也不决定复合中空纤维 相似文献