聚砜热相转移膜的研制

探讨了铸膜液温度、特性粘度、聚砜浓度、流涎温度和十二烷基苯磺酸钠添加量等对聚砜热相转移膜性能的影响，制得了平均孔径为０．８４μｍ、０．３４μｍ、０．１６μｍ的平板微孔膜。经扫描电镜观察，该膜具有对称的球状孔结构，为热相转移聚砜微孔膜。     

湿法相分离不对称超滤膜形成机理

本文选择了憎水的极怀非普质子性聚砜和亲水的极性质子怀聚砜酰胺两种膜材料，从铸膜液组成和凝胶过程两方面，用气相色谱和高效液相色谱研究了表征膜材料－溶剂－添加剂－水作用力的混合自由焓，平衡分配常数，及其与膜性能，不同溶剂特性粘度，雾点值和溶解度参数的关系，提出了铸膜液中有机溶剂的作用机理，及不对称超滤膜形成的一些规律。     

聚砜比浓粘度的预报和优化控制

本文用回归分析方法,得到合成聚砜塑料过程的宏观数学模型,实现聚砜塑料分子量间接测定值比浓粘度的预报和控制。进一步,对生产控制条件进行优化,从而获得分子量较稳定的聚合物。     

MULTICOMPONENT TRANSPORT OF ELECTROLYTES THROUGH CELLULOSE ACETATE MEMBRANES

A multicomponent transport model is presented to describe the rejection components of electrolyte systems by cellulose acetate reverse osmosis membranes. Comparison of the model with the experimental results obtained with NaCl-CaCl₂-H₂O solutions shows good agreement. It was observed that the presence of CaCl₂ can reduce drastically the rejection of NaCl in this multicomponent system and even cause 'negative rejection' in certain cases. The results of this study will be helpful in better understanding, predicting and controlling the operation of reverse osmosis desalination plants that process multicomponent feeds where interactions among the electrolytes present can affect the performance of the membranes used     

乳液聚合导致一种新的转相过程

借助电导率仪、光学显微镜和亚微粒子分析仪等测试手段。研究了乳液聚合导致一种新的转相过程,并用于八甲基环四硅氧烷的聚合中。研究表明:体系以 W/O 相态开始,单体由连续相向水相(分散相)内的胶束中扩散并发生聚合反应,形成 O/W/O 复合乳液。反应过程中连续相体积不断减小,分散相(O/W 复相)体积不断增大,当达到某一临界相比时,体系发生转相,转相后乳液为 O/W。对本实验物系,转相点临界相比主要由初始水油比和乳化剂浓度决定。同常规的乳液聚合相比,伴有转相现象的乳液聚合有其自身的特点,转相使得聚合速率、聚合物粒径及分布、乳液稳定性等发生变化。     

聚砜平板超滤膜的制备及性能优化

采用相转化法制备聚砜(PSF)平板超滤膜,通过正交试验确定了较佳制膜条件和各影响因素对膜性能的影响程度(PSF含量>溶剂种类>PVP含量>蒸发时间).在综合考虑经济性和膜性能优化的前提下,由单因素试验探讨了PSF含量、添加剂聚乙烯吡咯烷酮(PVP)含量及第2种溶剂N-甲基吡咯烷酮、二甲基亚砜的添加量对膜性能的影响.结果表明,最优化制膜条件为:PSF和PVP的质量分数分别为13.5%和3%,溶剂为二甲基亚砜和二甲基甲酰胺混合物且体积比为1:5,蒸发时间为10 s.在此条件下,膜将保持原有高截留率并使纯水通量得到较大提高.     

PSF/SPSF相容性对合金膜结构和性能的影响

通过混合焓法预测并用相差显微镜表征了PSF/SPSF合金体系的相容性，表明二者为部分相容体系，合金膜中聚合物的组成和铸膜液中溶剂的性能影响PSF/SPSF间的相容性，进而影响合金膜的结构和性能。随合金体系相容性下降，膜的平均孔径显著增加，水通量增大而相应的截留率下降，研究表明，改变PSF/SPSF间的相容性是调节膜结构，提高膜性能的有效方法。     

用相转换法制备非对称膜的凝胶动力学研究

本文采用了一套先进的实验装置来测定用相转换法制备非对称膜的凝胶速度，得到了和Ｓｔｒａｔｈｍａｎｎ等人不同的结果。实验结果及理论分析表明，凝胶动力学过程不能简单地用一个Ｆｉｃｋ扩散定律来描述。本文提出可以用凝胶速度常数Ｋ来表征凝胶速度和生态的膜结构。     

制膜基底对非溶剂致相转化法PVDF膜结构与性能的影响

以聚偏氟乙烯(PVDF)/N,N-二甲基乙酰胺–辛醇/水为制膜体系,采用干、湿相转化法制膜。考察了制膜基底对膜结构、表面浸润性和透过性能的影响。对膜样品的XRD测试表明,具有一定粗糙度的砂纸基底对液态膜具有粘附限制作用,在成膜过程中的液–固分相与液–液分相的竞争中占据更大优势。在适当粗糙度的砂纸基底上可以制得底面高度疏水且透过性能良好的PVDF微孔膜。     

聚乙烯醇/碳纳米管复合超滤膜的制备及应用研究

以聚乙烯醇(PVA)为基膜材料,以羧基化碳纳米管(c-CNT)为添加剂,采用浸没沉淀相转化法制备了一种新颖的PVA/c-CNT复合超滤膜.考察了c-CNT的用量对膜力学性能、水通量、截留率及耐污染性能的影响.结果表明,当c-CNT用量为2份时,复合超滤膜的拉伸性能、水通量、截留率均达到最佳,膜的抗污染能力得到提高.分别...     

聚砜类膜和膜材的改性

聚砜膜广泛应用于生物学分离上，但由于其蛋白质污染问题，导致膜的通透率下降，选择性改变。目前解决这一问题的办法是对膜或膜材进行亲水性改性。就聚砜类膜和膜材的改性情况作一概述，对比各种方法的优缺点，对聚砜类膜和膜材改性前景进行了展望。     

相态逆转及其密度波的不稳定性

在长度／直径比为1250的水平管内研究了液液相态逆转现象及其对油水两相流和油气水多相流水动力特性的影响．以双流体模型为基础,考虑悬浮相所受的雷诺应力,提出了描述气液两相流和液液两相流中密度波不稳定性的通用模型．模型计算结果表明,“水包油”流型与“油包水”流型之间的相态逆转在悬浮相体积分数为0.3左右发生,与经验性结论相吻合,揭示了相态逆转的机理．     

聚砜超滤膜的表面改性

本文用亲水性高分子，表面活性剂及丙烯酸化学反应对聚砜超滤膜进行表面改性，实验结果表明：丙烯酸化学改性效果最佳，可以同时提高膜通量，截留率及膜的抗污染性能。     

COMPETITIVE FACILITATED TRANSPORT OF ACID GASES IN MODIFIED CARRIER MEMBRANES

1 INTRODUCTIONMany attempts to develop semipermeable membranes for gas separation have beendone over the past twenty years [1,2].However,it is still difficult to prepare apolymer film which makes certain gas separation processed within range of being econ-omically and technically feasible,since most polymeric materials are relativelyimpermeable to gases.Facilitated transport concept which was first proposed by     

聚合物浓度对PSF/SPSF合金膜性能的影响

用膜材料液相共混制备了PSF／SPSF高分子分离膜，介绍了聚合物的浓度对不同组成的PSF／SPSF合金膜的渗透，分离性能和成膜性能，机械性能的影响，表明聚合物浓度增加，合金膜铸膜液的粘度增大，合金膜的截留率上升，水通量下降，合金膜的成膜性能和机械性能改善，上述变化规律与单一聚合物分离膜一致，与PSF／SPSF间的相容性无关。     

REVIEW OF REVERSE OSMOSIS MEMBRANES AND TRANSPORT MODELS

After a brief introduction to membrane processes in general, and the reverse osmosis process in particular, the structure and properties of membranes and membrane transport theory are described. The mechanism of salt rejection and transport properties of membranes are discussed in detail. Solubility, diffusivity, and permeability of membranes to solutes and solvents are reviewed critically and compared with each other. Special attention is given to two particular types of membranes, cellulose acetate (CA) and aromatic polyamide (AP) membranes, which are often used for water desalination.

The major portion of this article is devoted to the review and discussion of membrane transport theory with application to the reverse osmosis and ultrafiltralion processes. It is shown that the solvent flux can be represented reasonably well by linear models such as the solution-diffusion model (Lonsdale, et al., 1965). The contribution of pore flow to the solvent flux is small. The solute flux, however, is not linearly dependent on the driving forces and one has to solve the differential equation of transport within the membrane which results in models such as the Spiegler-Kedem (1966) or the finely-porous (Merten, 1966) models. When the wall Peclet number is small, Pe_w =uτδ/D_sw ?1, (D_sw = bD_e one can linearize the nonlinear models. This requirement is not satisfied in most practical cases. Furthermore, the pore flow has significant effect on the solute flux equation and thus it can not be neglected.

The ambiguities that exist in the literature concerning the types of fluxes are discussed. The fluxes used in models derived from irreversible thermodynamics are purely diffusive (concentration and pressure diffusion) and they do not contain any convective effects; whereas the experimentally observed fluxes are the total fluxes with respect to the membrane which consist of a diffusive flux and a convective flux. A new model, based on irreversible thermodynamics, is derived which includes a convective term.

A membrane model is especially useful when the transport coefficients which define the model are not functions of the driving forces, i.e., pressure and concentration gradients. The coefficients in the solution diffusion and sotution-diffusion-imperfection (Sherwood, et al., 1967) models are functions of both pressure and concentration, while the coefficients in the Kedem-Katchalsky (1958) model are relatively insensitive to pressure and concentration. The nonlinear model of Spiegler-Kedem (1966) further improves the Kedem-Katchalsky model.