破乳剂对复合驱乳状液的破乳机理研究

针对模拟采出液和三元复合驱矿场采出液,研究了破乳剂对复合体系界面张力和膜强度的影响.破乳剂浓度增加,二元复合体系界面张力降低,而三元复合体系界面张力升高.破乳剂分子部分顶替乳化剂分子并显著降低了界面膜强度.     

Simulation of an ultrafiltration process of bovine serum albumin in hollow-fiber membranes

This work presents a numerical simulation of an ultrafiltration process of bovine serum albumin in solution, using hollow-fiber membranes. Such membranes are constituted of tiny polymer cylinders disposed in a tube-and-shell arrangement. The concentrate flows through the interior of the fibers and the pure solvent is recovered in the shell, assuming perfect solute rejection. In modeling the process, the flow of concentrate inside the fibers was considered to be laminar, with constant density, viscosity and solute diffusivity. Axial diffusion and angular effects were ignored. The model combines the effect of concentration polarization and adsorption, which are the two main limiting phenomena in ultrafiltration processes. The pressure on the shell side was considered constant and inside the fibers a linear pressure profile, dependent on the axial position, was adopted. The solution of the problem was achieved with the method of orthogonal collocation, with adequate choice of the weight function in the radial direction. In the axial direction, a finite-difference method was used. The numerical results were compared with experimental data available in the literature.     

膜分离与分离膜

本文扼要阐述了膜分离技术的基本原理、特点、内容及其近５０年来的进展和在工业上的广泛应用,系统地叙述了目前应用最广泛的有机高分子膜的。文章分析了今后膜分离的发展动向并简要介绍了我国的有关情况。     

锌金属硫蛋白预防甲基汞对细胞膜损伤作用的实验研究

不同剂量的Ｚｎ可以诱导小鼠肝脏产生ＺｎＭＴ,随着实验组Ｚｎ剂量的增加,肝脏内ＺｎＭＴ的含量也相应增加,呈剂量效应增加（ｒ＝０．９９６）。ＺｎＭＴ具有保护膜构象、膜ＳＨ基、拮抗ＭｅＨｇ对膜流动性及膜通透性的损伤作用。本实验结果为ＺｎＭＴ预防甲基汞中毒提供了科学依据,同时显示了诱导ＺｎＭＴ的锌剂量要适当,过高则有毒性作用。     

Asymmetric molecular sieve carbon membranes

An asymmetric molecular sieve carbon membrane is obtained by conventional pyrolysis of a thermosetting polymeric film, followed by unequal oxidation. Morphology, pore size distribution, and gas separation characteristics of the membrane are discussed. The transport mechanism for gas permeation is clearly non-Knudsen diffusion since heavier oxygen permeates faster than lighter nitrogen. The proposed mass transfer mechanism is that of a molecular sieve.     

Structure and sorption characteristics of bioaffinity membranes

The new bioaffinity membranes comprise mammalian blood and tissue cells immobilized in the polymer matrix. The method of immobilization does not assume the retention of physiological and enzymatic activity of immobilized cells, but it ensures the safety of cellular membrane receptors that are used as specific ligands. Macroporous polymer carriers based on polyacrylonitrile maintain the accessibility of the cellular receptors for all blood plasma components including immunoglobulins and viral particles. The sorption capacity of membranes with respect to model substances in a batchwise technique is evaluated. Although the results are of a preliminary nature, the membranes may be used in crossflow modules for selective blood plasma correction of endogenous substances.     

A novel composite chitosan membrane for the separation of alcohol-water mixtures

A novel alcohol dehydration membrane with a three layer structure has been prepared. The top layer is a thin dense film of chitosan (CS), and the support layer is made of microporous polyacrylonitrile (PAN). Between the dense and microporous layer, there is an intermolecular cross-linking layer. This novel composite membrane has a high separation factor of more than 8000 and a good permeation rate of 0.26 kg/m² h for the pervaporation of 90 wt% ethanol aqueous solution at 60°C, 0.8 kg/m² h flux for a n-PrOH/water system and around 1 kg/m² h flux for an i-PrOH/water system using 80 wt% alcohol concentration at 60°C. The separation factor for both cases is more than 10⁵. The separation performance varies with feed composition, operating temperature and conditions of membrane preparation. The results show that the separation factor and flux of this membrane increase with raising the operating temperature. At the same time, the crosslinking layer improves durability of the composite membrane, and the pervaporation performance can be adjusted by changing the structure of the cross-linking layer. The cross section of the composite membrane has been examined by SEM.     

纳滤膜新型材料研究

纳滤是一种介于超滤与反渗透之间的重要膜分离过程,具有工作压力低、无相转变及分离效率高等独特优势。膜污染及渗透性/选择性之间的平衡是纳滤膜在使用和研发过程中面临的亟待解决的两个主要问题。膜材料是膜与膜分离技术的核心,开发新型的纳滤膜材料是解决上述问题的重要手段。本文从新型纳滤膜材料的设计与选择的角度出发,总结归纳了近年来新型材料在纳滤膜的制备与应用研究现状,包括新型有机纳滤膜材料、新型无机纳滤膜材料和新型有机-无机杂化纳滤膜材料三个方面,拓展了对纳滤膜材料的认知,探讨了新型纳滤膜材料的共性及其存在的主要问题,并对未来高性能纳滤膜材料的研制方向进行了展望。     

预涂布晶种法合成无缺陷A型分子筛膜的研究

采用一种颗粒度约为200nm的胶态A型分子筛为晶种源,对晶种层进行特殊的蒸气处理后,进一步采取原位水热晶化法,在多孔氧化铝载体表面制备出A型分子筛膜。膜分子筛以特殊的孪生聚晶形式生长在一起,可有效地消除晶粒间隙,形成致密的分子筛膜层。晶化反应液的碱度对A型分子筛膜的质量影响很大,低碱度更有利于A型分子筛膜的生长。在对分子筛膜进行高温活化处理过程中产生一些缺陷孔,降低了膜气体分离性能。     

用荧光葡聚糖研究大麦细胞电融合

利用阴离子表面活性物质荧光葡聚糖 (F DX)研究了表面活性物质对大麦细胞电融合的影响 .结果表明 ,F DX可抑制电融合过程 .对放置过大麦细胞原生质体的F DX溶液 ,在荧光显微镜下可观察到其膜表面的荧光圈 ,证明F DX在膜上的吸附 .添加F DX可增加原生质体的电泳速度 ,说明吸附后原生质体表面负电荷增多 .由于相互间静电斥力的增强 ,使细胞的电融合率下降 .此外 ,还利用荧光显微技术研究了细胞电生孔现象 .观察到经电脉冲后溶液中的F DX可进入原生质体内部 ,间接证明了细胞电生孔的存在 .