气体分离用聚砜中空纤维膜的活化涂敷技术

主要探讨了一些表面活性剂对气体分离用聚砜中空纤维膜表面涂敷上的作用。结果表明 ,其中TO 80对提高H2 /N2 分离系数的效果最佳。     

磺化聚砜对聚砜中空纤维膜结构与性能的影响

以聚乙二醇(PEG)为添加剂,二甲基乙酰胺(DMAc)为溶剂,采用浸没沉淀法制备了磺化聚砜(SPSF)/聚砜(PSF)中空纤维膜,考察了SPSF对聚砜中空纤维膜结构及性能的影响。实验结果表明:添加SPSF后,因其在分子链中产生的极性磺酸基团,使聚砜膜的表面接触角从94.7°降低到75°,平均孔径增加15.8%,其纯水通量较之未加入SPSF大幅提高,纯水通量从未添加SPSF时的129.2 L/(m~2·h)增加到了312.4 L/(m~2·h)。当SPSF质量分数为1.5%,PEG/DMAc为35/45,空气间隙为5 cm时,膜的综合性能最好。此时,纯水通量为302.6 L/(m~2·h),对牛血清蛋白溶液(BSA)的截留率为93.1%,孔隙率为76.1%,平均孔径55.2 nm,拉伸强度为4.89 MPa。     

人工肾中空纤维膜传质特性的实验研究

一方面采用纹影、全息干涉等流动显示方法,着眼于人工肾的内部透析流场,基于流动、传质等流体动力学的观点研究了人工肾的运行机理,观察了人工肾模型的内部流动特性,给出了浓度分布等重要参数的某些规律;另一方面通过自行研制中空纤维膜,为进一步揭示透析膜制备过程中的流变过程、微观结构与宏观的透析流场、清除效果的内在联系提供坚实和可靠的手段.实验结果表明,纹影和全息干涉方法不仅能显示人工肾模型透析过程中的流场结构,而且还可以定量测量其传质过程中的质量分布,是研究人工肾透析机理的非常有效的手段.     

Ultrafiltration of Myoglobin using Surface-Sulfonated Polysulfone Hollow Fiber

The usage of ionic polysulfone (PSF) hollow fiber for the ultrafiltration of protein was investigated. The surface of polysulfone hollow fiber was sulfonated through the Blanc chloromethylation reaction to become anionic. Characterization of the modified hollow fiber was performed including ion exchange titration, pure water permeation, and molecular sieving measurement. The performance of ultrafiltration of protein was evaluated using myoglobin at various pH values. The results show that the water contact angles and hydraulic resistance are markedly decreased, indicating that the surface-modified PSF hollow fibers are more hydrophilic. In addition, the retention of myoglobin depends on the pH of the solution. At a pH higher than the isoelectric point of myoglobin, both hollow fiber and the protein have the same charge sign, and both the flux of the solution and the retention are the highest. The sulfonated PSF hollow fiber may be used as a biomaterial for protein separation and purification.     

聚砜中空纤维膜的亲水改性研究

将吐温80或磺化聚砜(SPSF)加入聚砜-聚乙二醇400-二甲基乙酰胺(PSF–PEG400–DMAc)体系,共混制成均一铸膜液,采用浸入沉淀相转化法制备聚砜中空纤维超滤膜,考察吐温80或SPSF对聚砜中空纤维膜的亲水改性效果。对膜结构、铸膜液黏度、纯水通量、截留率、拉伸强度等进行了表征。研究结果表明,SPSF相比吐温80对膜的亲水性改善更明显。当SPSF质量分数为1.5%时,就可将PSF中空纤维膜的纯水通量提高一倍以上,膜纯水通量达到302 L/(m~2·h),对牛血清白蛋白(BSA)的截留率达到93%。     

Thermal Explosion of a Gas Mixture in a Porous Hollow Cylinder

A nonstationary model of gas combustion in a porous cylindrical heat generator with allowance for heat losses inside the body and from the outer surface is proposed and numerically analyzed. The flow pattern is demonstrated to depend on the ratio of the outer and inner radii of the working region. Critical conditions separating the stationary operation mode and the thermal explosion are found.     

PE-HD/CF/HGB三元复合材料的制备及力学性能

以高密度聚乙烯(PE-HD)为基体、碳纤维(CF)为增强材料,采用双辊塑炼工艺制备了PE-HD/CF复合材料,力学性能测试结果表明该复合材料的拉伸和弯曲性能随CF含量的增加而增大,但缺口冲击强度逐渐下降。在该复合材料基础上添加空心玻璃微珠(HGB)制得PE-HD/CF/HGB三元复合材料,力学性能测试结果表明当HGB用量为10份且CF用量为15份时,三元复合材料的拉伸强度、弯曲强度和缺口冲击强度均达到最大,分别为46.98 MPa,45.69 MPa和8.17 kJ/m2,较未加HGB的PE-HD/CF复合材料分别提高了7.19%,4.17%和10.4%。扫描电子显微镜结果表明,HGB主要通过其变形和破坏来吸收冲击能量,从而提高复合材料的韧性。     

The Calculation of a Serial Fed Gas Permeator System

Abstract

The calculation methods for the serial fed multistage system were developed for the four flow pattern, i.e., perfect mixing, cocurrent flow, cross flow, and countercurrent flow, under the condition of constant membrane area or constant cut. The calculations were performed for two examples using permeabilities of polyimide. One is the case in which concentrate H₂ is up to 95% in the total permeate stream from a 75% H2–25% CO mixture. Another is the case in which concentrate CH4 is up to 98% in the high-pressure stream from a 60% CH₄-40% CO₂ mixture. A brief parametric study shows that the system consisting of countercurrent flow modules under the condition of constant cut is most efficient among the case studied and should minimize the number of stages using big modules. On the other hand, the system composed of perfect mixing or cocurrent flow modules under the condition of constant membrane area is more efficient than constant cut, and it is advantageous to assemble a system using a large number of small modules. The performance of the system comprised of cross flow modules is identical with that of a single module.     

碳纤维/空心玻璃微珠/聚丙烯三元复合体系的制备及力学性能研究

以聚丙烯(PP)为基体、碳纤维(CF)为增强材料、空心玻璃微珠(HGB)为增韧剂制备了CF/HGB/PP三元复合体系,研究了CF、HGB含量对复合体系力学性能的影响,并对复合体系的微观结构进行了分析。结果表明:当CF含量为5份、HGB含量为15份时,CF/HGB/PP三元复合体系的综合力学性能最佳,其拉伸强度和缺口冲击强度分别比纯PP提高了46.5%和17.6%。     

The Transport of Copper(II) through Hollow Fiber Renewal Liquid Membrane and Hollow Fiber Supported Liquid Membrane

Abstract

In this paper, hollow fiber renewal liquid membrane (HFRLM) and hollow fiber supported liquid membrane (HFSLM) were used to simultaneously remove and recover copper(II) from aqueous solutions, and the transport performance of these two techniques were compared under the similar conditions for the system of CuSO₄ +D2EHPA in kerosene +HCl. The results showed that the HFRLM process was more stable than the HFSLM process. The HFRLM process had a higher overall mass transfer coefficient than that of HFSLM process in single-pass experiments. These were because the renewal effect of the liquid membrane layer could reduce the mass transfer resistance of the lumen side and replenish the loss of the membrane liquid in the HFRLM process. The transport results were better in the HFRLM process than that in the HFSLM process with recycling experiments. Therefore, HFRLM technique is a promising method for simultaneous removal and recovery of heavy metal from aqueous solutions.     

中空纤维膜吸收烟气二氧化硫

本文综述了国内外用膜吸收法治理烟气二氧化硫的研究现状,对采用中空纤维膜吸收过程中的膜组件操作方式、吸收剂、膜材料以及工艺参数的选择进行了介绍,并应用双膜理论对中空纤维膜吸收二氧化硫过程中的各分传质系数和总传质系数进行了推导,初步探讨了建立膜吸收过程数学模型的方法。     

Performance of Gas Separator with High-Flux Polyimide Hollow Fiber Membrane

Abstract

The permeation properties of H₂-CO mixtures through a high-flux asymmetric polyimide membrane are studied experimentally and theoretically. Experimental results measured with miniature module-equipped hollow fibers indicate the advantage of countercurrent flow pattern. The calculation model used for the analysis of the conventional symmetric membrane can predict the gas separation performance. However, the model is necessary to take the longitudinal mixing into account for analyzing the experimental results measured with a pilot scale module.     

An Explicit Solution for Concentration Polarization for Gas Separation in a Hollow Fiber Membrane

In the present work, a one-dimensional mathematical model is developed to analyze the concentration polarization phenomenon for the separation of gas mixtures in composite hollow fiber membranes. An analytical expression is developed for determining the interfacial concentration at the interface of dense and porous support layers. Further, the model accounts for the non-ideality of the gas mixture. Both co-current and counter-current flow configurations for the separation of hydrogen from a three-component mixture are studied. The effects of feed side pressure and velocity as well as permeability on concentration polarization are probed. It is apparent from this study that the concentration polarization phenomenon significantly affects the separation efficiency at higher permeability values.     

Permeation of Gas Mixtures in Cellulose Acetate Membranes Practical Approach to Predict the Permeation Rate Co2/Ch4 Mixture

Abstract

Dry cellulose acetate reverse osmosis membranes of different porosities are prepared by using the solvent exchange method and then shrunk at various temperatures.     

Facilitated Transport of Zinc Chloride through Hollow Fiber Supported Liquid Membrane. Part 1. Transport Mechanism

Abstract

The facilitated transport of zinc chloride through a liquid membrane of tri-n-octylamine dissolved in n-dodecane with 2-ethylhexyl alcohol, supported on a microporous polyethylene hollow fiber, has been studied in a series of three papers. This first paper deals with the transport mechanism. The distribution of zinc chloride between the liquid membrane phase and the aqueous hydrochloric acid solution was clarified. The characteristics of the support membrane and of the flow system were examined through phenol transport experiments. The initial permeation rate of zinc chloride was explained by the sum of film resistances in the two aqueous phases and a membrane phase resistance     

制备条件对聚酰亚胺中空纤维膜性能影响的研究进展

综述了内部和外部凝固剂的化学性质、凝固浴温度等对聚酰亚胺（PI）中空纤维的形态和对PI中空纤维膜的气体分离,性能的影响。同时,叙述了纤维塑化抑制和亚胺化条件控制等对提高PI中空纤维膜分离性能的作用.     

Thermal and Barrier Properties of Organoclay-filled Polysulfone Nanocomposites

Organo-modified fluorohectorite (OFH) clay-filled polysulfone (PSf) nanocomposites were prepared by a solution casting method. The dispersion of OFH clay in PSf nanocomposites was investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Thermal analysis revealed that incorporation of organoclay increased the thermal stability and glass transition temperature (T_g) of nanocomposites. The barrier properties of the nanocomposites studied were found to be significantly improved. It is worth mentioning that the improved thermal stability and barrier performance of these nanocomposites with the addition of organoclay in PSf matrix obviously offers immense potential in industrial and automobile applications.     

聚酰亚胺中空纤维气体分离膜的物理老化现象

以聚酰亚胺6FDA-mPDA为原料制备了单层非对称中空纤维膜,以聚酰亚胺Matrimid5218为分离层材料制备了双层非对称中空纤维膜,膜的致密层厚度为0.09~0.21μm。测试了中空纤维膜的O2、N2、CH4和CO2等气体渗透性能随时间的变化,研究了中空纤维膜物理老化现象。结果表明,随着老化的进行,气体渗透速率逐渐减小,分离系数逐渐变大,直至平衡。以自由体积扩散机理为基础,针对非对称中空纤维膜具有超薄皮层的特点,建立描述物理老化过程的数学模型。结果表明,该模型与实验结果相吻合,表明自由体积扩散机理可用来描述具有超薄皮层的中空纤维膜的物理老化现象。     

聚砜微观结构及热性能研究

采用ＦＴＩＲ、Ｈ－ＮＭＲ、ＤＴＡ、ＴＧＡ等测试方法对国产聚砜（ＳＧ－９０）及进口聚砜ＵＣＣ－８０进行了表征，证实二者均为线形双酚Ａ型聚砜，具有相同的微观结构。通过求算样品的热分解活化能，分析了聚砜热降解的机理。试验表明，样品中杂质的含量及聚合物端羟基的含量是影响样品热稳定性的原因之一。杂质存在时，氧气对聚砜的热降解有较大影响，因而聚合物中杂质残留溶剂的去除及对端羟基进行封端对改善聚砜的热稳定性极有意义。