聚偏氟乙烯/聚二甲基硅氧烷渗透气化膜在丁醇分离中的应用

通过相转化法制备PVDF多孔支撑膜,在其上涂覆致密的PDMS分离层制备得到PVDF/PDMS复合膜,用于丁醇的分离纯化。以丁醇水溶液为原料液,流速为1.6 L·min-1,丁醇浓度为15 g·L-1,温度为37℃时,PVDF/PDMS复合膜的总通量为158.2 g·m-2·h-1,分离因子为17.3。向丁醇水溶液中按丁醇:丙酮:乙醇比例为6:3:1添加丙酮和乙醇模拟发酵液,PVDF/PDMS复合膜的总通量升高到189.5 g·m-2·h-1,分离因子降低到14.8。进一步考察了以丙酮-丁醇-乙醇(ABE)发酵液为原料液的渗透气化膜分离性能,发酵液中不存在菌体时,PVDF/PDMS复合膜的总通量和分离因子分别为120.2 g·m-2·h-1和19.7,而菌体存在时,复合膜的总通量和分离因子分别为122.1 g·m-2·h-1和16.7。与PDMS均质膜相比,PVDF/PDMS复合膜在丁醇分离过程中的分离性能有了显著的提升,具有潜在的应用价值。     

聚偏氟乙烯/聚二甲基硅氧烷渗透气化膜在丁醇分离中的应用

通过相转化法制备PVDF多孔支撑膜,在其上涂覆致密的PDMS分离层制备得到PVDF/PDMS复合膜,用于丁醇的分离纯化。以丁醇水溶液为原料液,流速为1.6 L·min^-1,丁醇浓度为15 g·L^-1,温度为37℃时, PVDF/PDMS复合膜的总通量为158.2 g·m^-2·h^-1,分离因子为17.3。向丁醇水溶液中按丁醇：丙酮：乙醇比例为6：3：1添加丙酮和乙醇模拟发酵液,PVDF/PDMS复合膜的总通量升高到189.5 g·m^-2·h^-1,分离因子降低到14.8。进一步考察了以丙酮-丁醇-乙醇（ABE）发酵液为原料液的渗透气化膜分离性能,发酵液中不存在菌体时,PVDF/PDMS复合膜的总通量和分离因子分别为120.2 g·m^-2·h^-1和19.7,而菌体存在时,复合膜的总通量和分离因子分别为122.1 g·m^-2·h^-1和16.7。与PDMS均质膜相比,PVDF/PDMS复合膜在丁醇分离过程中的分离性能有了显著的提升, 具有潜在的应用价值。     

沸石填充硅橡胶渗透汽化膜的制备及其优先透醇性能研究

由ZSM-5沸石和聚二甲基硅氧烷(PDMS)制备超薄沸石填充PDMS复合膜,考察沸石填充量、沸石结构中硅铝比和操作温度对沸石填充硅橡胶膜渗透汽化性能的影响。结果表明,超薄复合膜的制备可以改善渗透通量小的缺陷。沸石填充量30%时分离因子最大;具有相同填充量的PDMS膜,硅铝比较大的填充膜,其分离因子和渗透通量均较高;随着操作温度的升高,复合膜分离因子先升高后降低,在50℃达到最大值,其渗透通量呈升高趋势。     

沸石填充硅橡胶渗透汽化膜的制备及其优先透醇性能研究

由ZSM-5沸石和聚二甲基硅氧烷(PDMS)制备超薄沸石填充PDMS复合膜,考察沸石填充量、沸石结构中硅铝比和操作温度对沸石填充硅橡胶膜渗透汽化性能的影响。结果表明,超薄复合膜的制备可以改善渗透通量小的缺陷。沸石填充量30%时分离因子最大;具有相同填充量的PDMS膜,硅铝比较大的填充膜,其分离因子和渗透通量均较高;随着操作温度的升高,复合膜分离因子先升高后降低,在50℃达到最大值,其渗透通量呈升高趋势。     

PDMS/ZSM-5膜的制备及渗透汽化分离水中乙酸正丁酯和乙酸乙酯

为探究出适合分离水中的乙酸正丁酯和乙酸乙酯的新型渗透汽化膜材料，选用沸石ZSM-5 对聚二甲基硅氧烷(PDMS)材料进行填充改性，以聚偏氟乙烯(PVDF)为支撑层，采用刮涂法制备PDMS/ZSM-5/PVDF复合膜渗透汽化分离水中的乙酸正丁酯和乙酸乙酯。采用SEM、接触角测量仪、FTIR、TGA和XRD等对膜材料物理化学性能进行表征，考察了膜材料的溶胀行为及渗透汽化性能。结果表明，ZSM-5在 PDMS 膜中分散均匀，且没有发生化学作用，并提高了膜材料的疏水性和热稳定性。随着ZSM-5添加量的增加，膜在乙酸正丁酯和乙酸乙酯的溶胀度和待分离组分在膜材料中的扩散速率不断增加。随着进料浓度和温度的增加，渗透通量不断增大，分离因子先增大后减小。随着ZSM-5在PDMS/ZSM-5/PVDF复合膜中含量的增加，总渗透通量增加，而分离因子呈现先增加后减小的趋势。当添加量为10%（质量）时，分离因子达到最大值。对于乙酸正丁酯/水体系，渗透通量和分离因子最大值分别为319 g·m ^-2·h ^-1和131；而对于乙酸乙酯/水体系，渗透通量和分离因子最大值分别为1385 g·m ^-2·h ^-1和121。     

双组分加成型硅橡胶膜制备及其渗透汽化分离碳酸二甲酯/甲醇

制备了一系列双组分加成型硅橡胶(PDMS)膜及ZSM-5沸石填充PDMS复合膜,用于渗透汽化法分离甲醇,碳酸二甲酯混合物,考察了C6-530双组分硅橡胶A/B组分比例、后处理温度、沸石填充浓度、操作温度对渗透汽化分离性能的影响.     

支撑层结构对PTFE-PDMS复合膜渗透汽化性能的影响

以不同结构的聚四氟乙烯(PTFE)平板膜为支撑层、聚二甲基硅氧烷(PDMS)为活性层,通过表面涂覆方法制备PTFE-PDMS复合膜,并用于渗透汽化过程,以实现乙醇-水混合溶液的分离;研究了支撑层结构及制膜参数对其分离性能的影响。结果表明,支撑层结构对复合膜分离因子几乎无影响,对孔径大孔隙率高的支撑层,制膜时,PDMS聚合物向支撑层中渗入过多会使复合膜的渗透通量降低。PDMS聚合物向支撑层渗透形成的过渡层是复合膜传质阻力的重要部分,且过渡层厚,复合膜的耐溶胀性好。综合考虑渗透通量及分离因子,复合膜优化制备条件是交联剂正硅酸乙酯的质量分数4%,交联温度80℃,交联时间为5 h。     

乙醇发酵与渗透汽化在硅橡胶膜生物反应器中的耦合强化

用硅橡胶膜生物反应器(SMBR)实验研究了发酵-渗透汽化的耦合性能。发酵微生物采用酿酒活性干酵母,所用的碳源为工业级葡萄糖。间歇发酵过程由于产物抑制作用在乙醇浓度达到90g稬-1时就趋于停滞,而经耦合渗透汽化膜分离后,发酵罐内的乙醇浓度迅速降低并维持在40g稬-1,且发酵在此浓度下可以连续稳定地进行。 在SMBR运行达到稳态后,乙醇的体积产率为1.5gL-1h-1。SMBR中所用的聚二甲基硅氧烷(PDMS)复合膜由实验室自行制备,它能稳定分离含有酵母细胞的发酵液。当发酵液中乙醇浓度为92.7~49.5g稬-1时,PDMS复合膜的总通量为1490~1164g穖-2h-1,分离因子为6.9~7.8,与分离相同进料浓度的清洁模型溶液相比分别平均高出31%和14%。乙醇发酵和渗透汽化在硅橡胶膜生物反应器中能够相互耦合并得到强化。     

模拟的发酵液组分对聚二甲基硅氧烷/陶瓷复合膜渗透汽化性能的影响

对所制备的聚二甲基硅氧烷（PDMS）/陶瓷复合膜进行了渗透汽化性能表征。通过在乙醇-水混合体系中添加不同的模拟发酵液组分;如葡萄糖（多羟基醛）、甘油（多元醇）、丁二酸（有机酸）、KCl（无机盐）;考察了各组分对复合膜渗透汽化性能的影响。研究发现：在333 K下;在乙醇浓度为65 g·L-1的混合物中添加不同浓度的第三组分;有机添加物对膜的渗透汽化性能没有明显影响;而无机盐的加入使膜的分离因子稍有提高。所制备的PDMS/陶瓷复合膜;在上述渗透汽化过程中表现出良好的稳定性和对乙醇的优先选择性;渗透通量和分离因子（醇/水）分别在4.5～4.7 kg·m^-2·h^-1、8.3～10.3之间。     

聚二甲基硅氧烷-聚偏氟乙烯共混膜制备及其渗透蒸发性能研究

为增强聚偏氟乙烯(PVDF)膜的疏水性能和膜选择性能,在PVDF基膜材料中添加了不同质量的聚二甲基硅氧烷(PDMS),制备了PVDF-PDMS共混复合膜。考察了PDMS、PVDF质量比对复合膜结构性能的影响,并用扫描电子显微镜、比表面积孔径分析仪、接触角测量仪、傅里叶变换红外光谱仪、X射线光电子能谱仪等仪器对复合膜进行了表征;采用低含量苯酚水溶液研究了复合膜的渗透蒸发性能。结果表明,随着PDMS添加量的增加,复合膜的疏水性能、苯酚渗透通量以及分离因子都会逐渐增大,复合膜渗透蒸发性能明显优于未改性膜;在PDMS、PVDF质量比为1:10时,复合膜具有最好的形态结构,表面接触角达到82.92°,苯酚渗透通量为39.31 g/(m~2·h),分离因子增加到4.68。     

Separation of ethanol from ethanol/water mixtures by pervaporation with silicone rubber membranes: Effect of silicone rubbers

In this study, poly(dimethyl siloxane) (PDMS)/poly(vinylidene fluoride) (PVDF), poly(phenyl methyl siloxane) (PPMS)/PVDF, poly(ethoxy methyl siloxane) (PEOMS)/PVDF, and poly(trifluropropyl methyl siloxane) (PTFMS)/PVDF composite membranes were prepared. The different functional compositions of these membranes were characterized by Fourier transform infrared spectroscopy. The surfaces and sections of these membranes were investigated by scanning electron microscopy. The hydrophobicity at the membrane surface was assessed with contact angle measurement. Swelling experiments were carried out to investigate the swelling behavior of these membranes. The composite membranes prepared in this study were used in the pervaporation separation of ethanol/water mixtures, and their separation performances were compared. The results show that the separation performances of these membranes were strongly related to the silicone rubber components and composition, the total fluxes decreased in the following order: PDMS > PPMS > PEOMS > PTFMS. The separation factor followed the following order: PPMS > PEOMS > PDMS > PTFMS (5 wt % ethanol at 40°C). In addition, the effects of the feed temperature (40–70°C) and feed composition (5–20 wt %) on the separation efficiency were investigated experimentally. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

支撑层对硅橡胶复合膜渗透汽化分离性能的影响

引言 为了扩大渗透汽化技术的应用领域,科研工作者需要进一步增强渗透汽化膜的分离性能.从工业化的观点而言,用于实际应用的渗透汽化膜大多是复合膜,它由选择层(或分离层)和支撑层组成.一般认为,选择层决定着复合膜的选择性和通量,支撑层起支撑和机械稳定作用.Nijhuis[1]在从甲苯-水体系中分离甲苯的过程中对均质膜和以聚砜为支撑层的复合膜的分离性能进行了比较;Sturken[2]分别用聚醚酰亚胺和聚偏氟乙烯为支撑层的硅橡胶膜从二氯乙烷-水体系中提取二氯乙烷,他们得到了相同的结论:支撑层的影响可以忽略.然而Scholz[3],Heinzelmann[4],Rautenbach[5],Borges[6],Vankelecom[7],Farooq[8],Lipnizki[9]等均在各自研究中发现,由于基膜和分离层的物理化学性质以及制膜方法等众多因素的存在使得支撑层在一定程度上影响复合膜的分离性能;Feng[10]对均质硅橡胶膜和有微孔支撑层的硅橡胶复合膜的分离性能进行了比较,发现均质硅橡胶膜优先透过异丙醇,而有微孔亲水性支撑层的硅橡胶复合膜则优先透过水,这表明在一定的情况下,支撑层甚至起主导作用并能够决定复合膜的分离性能.因此,通过系统研究以不同多孔材料为支撑层的复合膜对有机物-水溶液的分离性能的影响,能够找到最优的复合膜支撑层,从而能够提高复合膜的分离性能.然而,至今关于支撑层对渗透汽化膜分离性能影响的系统研究仍相当少.     

纳米白炭黑填充硅橡胶复合膜的制备与渗透汽化分离性能

制备以聚酯(PET)为支撑层,白炭黑填充的聚二甲基硅氧烷(PDMS107)为皮层的硅橡胶复合膜,并以乙醇水物系为料液,对比分析白炭黑增强硅橡胶复合膜的渗透蒸发分离性能,分离因子比空白膜有所提高,在乙醇浓度为3%～5%时,分离因子可达16.09,渗透通量为75.39 g/m2·h;测定填充白炭黑硅橡胶复合膜的拉伸强度,结果表明:拉伸强度可达1.828 MPa,相当于空白膜(0.368 MPa)的5倍.     

有机硅烷交联PDMS/陶瓷复合膜的制备及渗透汽化汽油脱硫性能

采用有机硅烷γ-氨丙基三甲氧基硅氧烷（APTMS）,对聚二甲基硅氧烷（PDMS）进行交联改性,以ZrO₂/Al₂O₃陶瓷复合膜为支撑体,制备了一系列有机硅烷交联的PDMS/陶瓷复合膜。通过扫描电镜（SEM）、傅里叶红外光谱（FTIR）、热重分析（TGA）对改性效果和膜结构进行了表征。将所制备的PDMS/陶瓷复合膜应用于渗透汽化脱除模拟汽油中的有机硫化物（噻吩）,考察了交联剂APTMS含量、操作温度、料液含硫量等因素对复合膜渗透汽化脱硫性能的影响。实验结果表明,有机硅烷交联的PDMS膜相比于传统正硅酸乙酯（TEOS）交联的PDMS膜,通量和硫富集因子均有所提高。随着进料温度和原料液中硫含量的升高,膜的渗透通量均增大,而硫富集因子均减小。当APTMS质量分数为15%、进料温度为25℃、噻吩质量浓度为100mg/kg时,渗透通量为0.46 kg/（m²·h）,硫富集因子达到3.5。     

硅橡胶膜用于植物油/己烷胶团中溶剂回收的研究

Traditional solvent recovery in the extraction step of edible oil processing is distillation, which consumes large amounts of energy. If the distillation is replaced by membrane process, the energy consumption can be reduced greatly. In this work, two kinds of membrane, PDMS (polydimethylsiloxane) composite membrane and Zeolite filled PDMS membrane were prepared, in which asymmetric microporous PVDF (polyvinylidenefluoride) membrane prepared with phase inversion method was functioned as the microporous supporting layer in the flat-plate composite membrane. The different function compositions of the PDMS/PVDF com-posite membranes were characterized by reflection Fourier transform infrared (FTIR) spectroscopy. The surface and section of PDMS/PVDF composite membranes were investigated by scanning electron microscope (SEM). The PDMS NF (nanofiltration) membranes were then applied in the recovery of hexane from soybean oil/hexane miscellas (1︰3, mass ratio). The effects of pres-sure (0.5-1.5 MPa), cross-linking temperature and PDMS layer thickness on membrane performances were investigated. The results indicated that both two kinds of NF membranes were promising for solvent recovery, and zeolite filled in PDMS NF membrane could enhance the separation performance.     

Pervaporation for the Separation of Methyl Ethyl Ketone from Binary Process Mixtures

Abstract

The separation of methyl ethyl ketone (MEK) from binary process mixtures containing water and ethanol has been examined. These studies demonstrate the capability of pervaporation membranes to effectively separate MEK from various process streams in industry. Extensive organic permeation studies were performed using silicone composite membranes to evaluate the effect of temperature, permeate-side pressure, and feed concentration on flux and selectivity. Two organophilic membranes, a high selectivity low flux membrane and a low selectivity high flux membrane, were compared. Dehydration of a MEK-water mixture was also effectively performed with a polyvinyl alcohol composite membrane. MEK was separated only slightly from an ethanol mixture using a silicone membrane.     

超疏水聚偏氟乙烯复合微孔膜的制备及性能

提出了一种超疏水聚偏氟乙烯（PVDF）复合微孔膜的制备方法。以相转化法制备的PVDF膜为基膜,通过恒压过滤将多壁碳纳米管（MWCNTs）沉积到PVDF基膜表面,再经聚二甲基硅氧烷（PDMS）溶液修饰,可制得接触角达162°、滚动角约10°的PVDF复合微孔膜。用原子力显微镜和扫描电镜对膜表面进行结构分析,并测试了膜的接触角、气通量和机械强度等性能,考察了MWCNTs及PDMS浓度对膜结构和性能的影响。研究表明,CNTs在具有微米级粗糙度的基膜上强化了纳米结构,提高了膜的粗糙度,PDMS降低了膜的表面能,二者协同作用使复合膜的接触角大幅提高,滚动角显著下降。与高度疏水的PVDF基膜相比,PVDF复合膜的疏水性大幅提高,断裂伸长率加倍,在模拟海水真空膜蒸馏过程中,保持了较高的传质通量和截留率,具有更好的操作稳定性和抗污染性能。     

Preparation and characterization of Silicalite‐1/PDMS surface sieving pervaporation membrane for separation of ethanol/water mixture

To improve the pervaporation performance of Silicalite‐1/PDMS composite membrane by adding a small amount of Silicalite‐1 zeolite, novel Silicalite‐1/PDMS surface sieving membranes (SSMs) were prepared by attaching Silicalite‐1 particles on the PDMS membrane surface. The obtained membranes and traditional mixed‐matrix membranes (MMMs) were characterized by SEM, XRD, TGA, FT‐IR, and pervaporation separation of ethanol–water mixture. Effects of Silicalite‐1 particles content, feed temperatures, and feed compositions on the separation performance were discussed. From the cross‐section view SEM images of SSMs, a two‐layer structure was observed. The thickness of the Silicalite‐1 layer was about 300 nm to 2 μm. The TGA analysis indicates that the zeolite concentration in 3 wt % SSM is lower than 10 wt % MMMs. In the ethanol/water pervaporation experiment, the separation factor of Silicalite‐1/PDMS SSMs increased considerably compared with pure PDMS membrane. When the suspensions concentrations of Silicalite‐1 particles reached 3 wt %, the separation factor was about 217% increase over pure PDMS membrane and 52.9% increase over 10 wt % Silicalite‐1/PDMS MMMs. As the ethanol concentration in the feed increases, the separation factor of SSMs increases, whereas permeation flux decreases. At the same time, with increasing operating temperature, the permeation flux of SSMs increased. The stability of SSMs at high temperature is better than the traditional MMMs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42460.     

ZSM-5填充PDMS复合膜渗透蒸发分离乙醛水溶液(英文)

Hydrophobic ZSM-5 zeolite filled polydimethylsiloxane(PDMS) composite membranes with Nylon micro-filtration membrane as the support layer were prepared to separate acetaldehyde from its aqueous solution.The composite membranes were characterized by Fourier transform infrared spectroscopy and X-ray diffraction.Their structural morphology and thermal stability were also examined.The swelling study showed that the composite membranes presented higher degree of swelling in aqueous solution of acetaldehyde than in pure water at 25 C,suggesting that the membranes have stronger sorption capacity in acetaldehyde solution.The effects of ZSM-5 filling content and acetaldehyde concentration on pervaporation performance of composite membranes were investigated.The permeation experiments at different temperatures showed that both selectivity and permeation flux of composite membranes increased with temperature.With 5%ZSM-5-PDMS/Nylon membrane at acetaldehyde mass concentration of 8% and 25℃,the separation factor of acetaldehyde/water achieved 35 and the permeation flux was 233.3 g·m-2·h-1.     

不同交联剂对PDMS/PVDF纳滤膜溶剂回收性能的影响

以聚二甲基硅氧烷(PDMS)为分离层材料,聚偏氟乙烯(PVDF)超滤膜为底膜,采用正硅酸乙酯(TEOS)、苯基三甲氧基硅烷(PTMOS)、辛基三甲氧基硅烷(OTMOS)、γ-氨基丙基三乙氧基硅烷(APTEOS)4种不同的交联剂对PDMS进行交联,制备了PDMS/PVDF纳滤膜。采用接触角、红外谱图、扫描电镜等对膜的物理和化学结构进行了分析和表征。以大豆油/己烷混合油为实验体系,考察了压力和料液浓度对纳滤膜分离性能的影响。结果表明,纳滤膜的通量随压力线性增长,截留率初始随压力上升较快,随后增幅减慢而趋于稳定。随料液浓度的增加,纳滤膜的通量和截留率都有较大幅度的下降。相比较而言,以TEOS为交联剂所制得的纳滤膜分离性能最佳。大豆油/己烷混合油体系同水溶液体系的渗透特性类似,其渗透压可用van't Hoff方程计算。