新型渗透蒸发膜及其透醇性能研究

采用溶液聚合法合成聚丙烯酸,并利用聚丙烯酸和环氧树脂的交联作用制备出交联聚丙烯酸（ＰＡＡ）,在聚砜酰胺（ＰＳＡ）膜上涂膜形成ＰＡＡ－ＰＳＡ复合膜。发现用交联聚丙烯酸－聚砜酰胺制成的复合膜在渗透蒸发领域内具有应用价值。通过对低浓度乙醇－水的渗透蒸发的试验研究,表明该膜是一种性能较好的新型优先透醇膜。     

浓乳液聚合制备优先脱醇渗透蒸发分离膜

提出了一种以浓乳液聚合直接浇注制备新型有机硅类渗透蒸发分离膜的新方法。考察了乙醇浓度、分离时间与渗透蒸发分离性能之间的关系,表征了有机硅浓乳液聚合过程中的乳胶粒子形态与成膜后粒子堆砌的微观结构。结果表明,利用膜中乳胶粒子间微通道的极性效应可以有效地分离醇/水混合物中的醇,且优先脱醇效果明显,分离性能良好。在乙醇/水混合物的渗透蒸发膜分离实验中,其渗透通量为4.7～165g·m-2·h-1,分离因子为1.0～11.3,分离选择性最好时的料液中乙醇的质量分数为33.41%。     

交联聚乙烯醇渗透蒸发膜用于酯化反应过程

研究了交联聚乙烯渗透蒸发膜在酯化反应过程中的应用，以乙酸与正丁醇酯化反应为实验对象，通过渗透蒸发膜选择性地移走产物水，使最终反尖转化率超越平衡转化率，实验考察了温度，进料初始摩尔比，催化剂浓度对过程的影响。     

PDMS/PS复合膜的渗透蒸发性能的研究

制备了高性能的PDMS/PS复合膜,可将水溶液中苯的浓度由0.2～0.8×10-3kg·kg-1浓缩至70%～96%(质量分数),膜的渗透通量为0.10～0.4 kg·m-2·h-1,分离因子可达到20 000;通过渗透蒸发实验,考察了料液浓度、料液流速、料液温度和膜下游压力等操作条件对PDMS/PS复合膜渗透蒸发性能的影响;考察了活性层厚度和基膜结构分别对活性层传质阻力、基膜传质阻力的影响.并确定总传质阻力与活性层厚度的关系式和基膜传质阻力的经验公式.在此基础上得到了渗透蒸发的传质模型,计算结果与实验结果符合良好.     

硅橡胶复合膜用于渗透蒸发的膜传质动力学(Ⅰ)膜面上的对流传质

利用自制的硅橡胶平板复合膜对低浓度乙醇水溶液进行渗透蒸发分离乙醇实验 ,研究了过程的传质动力学。基于液 -膜的串联传质阻力模型 ,通过实验测定了膜的总传质系数 ,采用对比差值方法将总传质系数拆分为膜面上的液膜传质系数和膜内的扩散传质系数两部分 ,分析了液相边界层阻力和膜扩散阻力对总传质系数的影响。特别针对膜面上液体流动状况对膜传质的影响进行了探讨 ,得出了液膜传质系数与Reynolds数及温度的关联式。     

硅橡胶复合膜用于渗透蒸发的膜传质动力学(Ⅱ)膜内的扩散传质

The pervaporation of organics from dilute aqueous solution through a novel plate composite silicone rubber membrane was investigated. The measured and derived data indicated that the composite membrane possessed very high permeation flux and stable selectivity for dilute organic aqueous solution. Based upon the well- known resistance-in- series model, diffusive mass transfer behavior in membrane was investigated by calculation from the measured data with different skin layer thickness of membranes. The experimental results showed that the diffusive mass transfer coefficient conformed to Arrhenius correlation with temperature and was independent of the flow status. The diffusivities of the given alcohols in membrane had an order of magnitude 10 m-10·s-1 at a wider range of temperature, which is similar to those reported in literatures.     

碳分子筛填充硅橡胶膜用于渗透蒸发分离稀醋酸-水溶液

From the reference[1] it is known that the addition of silicalite-1 in silicone rubber membranes results in an increase of both flux and selectivity for alcohol in the separation of alcohol/water by pervaporation.In order to enhance performance of pervaporation toward the aqueous solution of acetic acid,incorporation of carbon molecular sieve(CMS)into a PDMS membrane was investigated. CMS is widely used in adsorption processes because of its high selectivity toward certain compounds[2]. It was assumed that the flux and selectivity of pure PDMS membrane could be enhanced owing to the preferential adsorption of CMS to organics.CMS content in the membrane and several important pervaporation operation parameters, including feed concentration of acetic acid, and feed temperature, were investigated.     

聚二甲基硅氧烷膜中乙醇-水的吸附和渗透蒸发行为

以乙醇/水体系为研究对象,结合F lory-Huggins理论,讨论溶胀过程的热力学行为,用以分析和考察聚二甲基硅氧烷(PDMS)膜在乙醇/水中的溶胀特性及组分间的耦合效应。结果表明,在乙醇质量分数20%—40%,膜的溶胀程度最大。渗透蒸发实验表明,水的渗透速率在乙醇质量分数不大于30%范围内变化很小,而乙醇的渗透速率基本随溶液中乙醇质量分数增加而增大。     

聚氨酯渗透蒸发膜的研究进展

综述了聚氨酯渗透蒸发膜在渗透蒸发分离中的研究进展,分析了聚氨酯膜软硬段结构及其它因素对其分离性能的影响,并对聚氨酯膜的改性方法进行总结和评述。指出了聚氨酯膜目前研究中存在的不足及发展趋势。     

渗透汽化技术脱除黄酒中乙醇的实验研究

在40℃,膜下游侧压力为260 Pa下,用自制的硅橡胶复合膜对传统黄酒进行了渗透汽化脱醇研究,重点对黄酒中10种主要风味物质和理化指标的变化进行了分析。实验结果表明,当乙醇的体积分数从25.1%降到6.5%时,黄酒中的乙醛、甲醇、乙酸乙酯和高级醇类的含量显著降低,乳酸乙酯的含量基本保持不变,而乙酸和苯乙醇的含量则增加了3~4倍。低醇黄酒的风味和口感与传统黄酒有较明显的差别,形成独特的风格,但总体上保持了传统黄酒的典型性,并且保健功能有所增强。硅橡胶复合膜的平均总渗透通量为1 500 g/(m2.h),对乙醇的平均分离因子为7.4。     

PDMS/陶瓷复合膜用于正丁醇-水体系的渗透汽化分离

Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from its aqueous solution using a polydimethylsiloxane (PDMS)/ceramic composite pervaporation membrane. The effects of operating temperature, feed concentration, feed flow rate and operating time on the membrane pervaporation per-formance were investigated. It was found that with the increase of temperature or butanol concentration in the feed, the total flux through the membrane increased while the separation factor decreased slightly. As the feed flow rate increased, the total flux increased gradually while the separation factor changed little. At 40 C and 1% (by mass) butanol in the feed, the total flux and separation factor of the membrane reached 457.4 g•m2•h1 and 26.1, respec-tively. The membrane with high flux is suitable for recovering butanol from ABE fermentation broth.     

硅橡胶复合膜用于新型白酒风味成分渗透汽化分离

用自制硅橡胶PDMS平板复合膜,分别在30、35、40℃和1325Pa膜下侧压力的条件下,渗透蒸发分离50°新型白酒中的风味物质。实验结果表明,PDMS复合膜对新型白酒风味物质具有良好的选择分离性能:5种酯类(乳酸乙酯除外)和乙缩醛的分离脱除率达100%,对高级醇也有良好的分离表现,乙醛的脱除率也超过87%。将分离后的酒液进行重组,得到较原酒品质更高的新酒,其感官评价大大好于原酒。膜在高浓度乙醇中能保持良好的稳定性,30、35和40℃时,对新型白酒的平均总渗透通量分别可达2297g/(m2·h)、2753g/(m2·h)和3539g/(m2·h),平均分离因子(均按乙醇-水体系计算)分别为5 22、5 22和5 32。     

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.     

A Review of Membrane Materials for Ethanol Recovery by Pervaporation

Due to an emerging scarcity of oil resources and an associated increase of oil prices, biofuels (e.g., ethanol) play an important role in the energy crisis. Fermentation is a common process for producing ethanol from renewable biomass. Pervaporation is an attractive technique for the recovery of ethanol from the fermentation systems. Separation membrane is the key element in the pervaporation separation equipments. In this article, the pervaporation performances of ethanol-permselective membranes presented in the recovery of ethanol from dilute ethanol aqueous solution are reviewed. An analytical overview on the challenges and opportunities, and the prospect of ethanol-permselective membranes by pervaporation is also discussed.     

丙炔醇-丁炔二醇-水溶液的渗透汽化分离研究

用PDMS复合膜从实际的丙炔醇-丁炔二醇-水溶液中渗透汽化分离丙炔醇。实验证明,膜渗透汽化可以实现丙炔醇的选择性分离,对水的分离因子可达3.78;丁炔二醇被膜完全截留;丙炔醇通量对温度具有敏感性,通量随着温度的增加上升得很快,丙炔醇通量在25℃时为45.28g/(m2.h),在60℃时为243.24g/(m2.h),显示了PDMS膜从这个体系中分离丙炔醇具有某种优势;对实验数据进行线性回归,证明丙炔醇通量和温度的关系可以用Arrhenius公式表征。为工业上用PDMS膜渗透汽化分离提纯丙炔醇提供参考。     

PDMS渗透汽化膜分离水中有机物的研究进展

渗透汽化(PV)膜分离技术是一种新型膜分离技术,适用于分离恒沸点混合物、近沸点溶液、热敏感性混合物、有机-有机混合物以及水溶液中少量有机物。PV分离水溶液中有机物的工业应用还处于初步阶段,文中从硅橡胶渗透汽化优先透有机物膜的制备条件、工艺应用参数及膜寿命等方面进行综述。膜生产放大和膜寿命是影响该技术推广的重要因素,可以从膜制备和应用工艺方面进行改进。     

乙酸与丁醇酯化反应和渗透蒸发耦合过程研究

以硫酸锆催化乙酸和丁醇的酯化反应为例对渗透蒸发和酯化反应耦合过程进行研究 ,考察了温度、反应物初始摩尔比、膜面积与反应液体积比和催化剂浓度对耦合过程的影响。     

Pervaporation of High Boiling Point Organic Compounds with Composite PDMS Membrane

High Boiling Point Organic Compounds (HBOCs ^{1 1}HBOCs: High Boiling Point Organic Compounds ) are defined as those organic compounds with boiling point over water (100°C). It is a challenging problem to separate HBOCs from their mixtures with water. Three HBOCs, propargyl alcohol, butanol, and pyridine, were selected as the experimental samples for observing their separation behaviors from water mixtures by PDMS membrane pervaporation. These HBOCs could preferentially permeate the PDMS membrane and were selectively extracted from the mixtures through the membrane. The experimental tests showed that the permeation flux of propargyl alcohol, butanol, and pyridine was 243.24, 976.5, and 904.70 gm^?2h^?1, with the corresponding selectivity of 3.78, 29.65, and 26.09, respectively. The effects of the feed flow rate, feed concentration, and temperature on the separation behaviors were examined. By comparison with distillation that separates different components in a mixture on the basis of boiling point, the membrane pervaporation seems to behave a “reverse direction” selective separation for the HBOCs. For those aqueous mixtures with tiny content of HBOCs, the “reverse selective separation” by membrane pervaporation should be considered as a promising and effective technology.     

Extraction of Tetrahydrofuran and Ethylene Dichloride Solvents from Aqueous Solutions by Pervaporation through Thin Film Composite PDMS Membranes

Thin film composite (TFC) hydrophobic PDMS membrane of 5 µm active layer thickness supported on Polyethersulfone (PES) ultraporous substrate was synthesized and thermally crosslinked for the pervaporation based extraction of organic solvents such as Tetrahydrofuran (THF) and Ethylenedichloride (EDC) for the first time. The study was extended to acetone, ethanol, t-butanol, Iso-butanol, and acetic acid. Membranes were characterized by SEM, TGA, XRD, and FTIR to study the surface and cross-sectional morphology, thermal stability, crystalline nature, and structural properties, respectively. High selectivities of 868, 72, and 31 were observed at organic feed concentrations of 0.68, 3.42, and 9.38 wt% in water with reasonable fluxes of 0.2, 0.16, and 0.31 kg m^?2 h^?1 for EDC, THF and acetone, respectively at a downstream vacuum of 0.5 mmHg. The estimated mass transfer coefficients (MTCs) were found to be 9.11 × 10^?6, 11.77 × 10^?6, and 10.73 × 10^?6 m s^?1 for THF, EDC, and acetone extraction, respectively. The membrane exhibited considerable feasibility for scale-up due to its composite nature with significant potential for extraction of volatile organic solvents present in low concentrations. A comparison with previous values reported in literature revealed higher selectivities for extraction of EDC, THF and acetone using the present membrane.