【作者】 张新晖；

【导师】 袁其朋；

【作者基本信息】 北京化工大学 ， 生物化工， 2004， 硕士

【摘要】 有机相纳米过滤是一种新型过滤技术，具有其它分离技术不可比拟的优点，在工业上具有广泛的应用前景。但是，由于人们对有机溶剂中纳滤传递机理的认识十分缺乏，限制了耐有机溶剂纳滤膜的开发以及有机相纳米过滤的广泛应用。因此，研究有机相纳滤传递机理具有非常重要的科学意义及实用价值。本文将宏观与微观方法相结合，对有机溶剂中纳滤膜的传递机理进行研究。利用AFM表征纳滤膜在不同条件下不同材料、不同种类膜微观结构的变化，再利用宏观实验得到纳滤传递及截留性能。在此基础上，研究纳滤膜的传递机理，建立数学模型。 实验首先观察了两种纳滤膜 (NF–SH, MPF–44)的稳定性，并利用原子力电镜技术(AFM)观察膜的活性表面结构，发现有机溶剂导致膜结构发生显著变化。观测在溶剂中的传递通量以及溶质截留率时，发现不同的膜影响其通量的因素不同：对NF-SH膜，其主要因素为浸泡有机溶剂后膜结构的变化；对MPF–44膜，其主要因素则是溶剂性质（溶剂的极性）。对于这两种膜影响截留率的主要因素都是溶剂与溶质的相互作用。实验并利用氢键模型解释了浸泡天数对膜通过特性的影响情况。利用NF-SH、Desal-DK和Les-90膜研究了操作条件对3种纯有机<WP=4>溶剂膜通量以及考马斯亮蓝甲醇溶液截留率的影响。结果表明，当透过溶剂为甲醇时，膜的压实效应比水明显；对于甲醇溶液，压力从0.5 Mpa升高到1.5 Mpa，溶质的截留率从48.5％降低到11.1％，表现出与水溶液中（截留率增大了12.4％）截然相反的趋势。通过研究温度对溶剂传递通量的影响，发现Hagen－Poiseuille 模型在有机溶剂中同样适用；对于甲醇溶液，温度从10℃升高到40℃，溶质的截留率从31.3％降低到19.7％，表现出了与水溶液（截留率增大了13.0％）相同的趋势。在甲醇溶液中，改变溶质浓度从1mg/l到30mg/l，发现在温度为20℃和40℃时截留率分别增大了19.2％和1.2％，在压力为1Mpa和1.5Mpa下，截留率分别增大了29.2％和1.6％，表明在较高的温度和压力下，浓度对截留率的影响较小。另外，实验还对纯溶剂与考马斯亮蓝溶液膜通量进行比较，发现在考马斯亮蓝的甲醇和乙醇溶液中，由于反射系数较小，通量较纯甲醇和乙醇溶剂的膜通量变化小。最后，实验考察了粘度、摩尔体积以及溶解性参数对纯溶剂透过系数的影响，拟合出透过系数与这些参数的关系式。结果表明，无论是同系溶剂还是非同系溶剂，对于亲水性纳滤膜，透过系数与3个参数的关系式均为A∝δ2/ Vmμ；而对于疏水性纳滤膜，透过系数与3个参数的关系式均为A∝1/ Vmμδ2。更多还原

【Abstract】 Nanofiltration has been proposed for uses in organic solutions. However, transport and retention data for NF membranes in organic solvents are very limited in the literature, and the mechanism of transport through NF membranes in organic solvent environments is not well understood, which restrict the applications of NF membranes in organic solvents. We believe that research of the mechanism of NF membranes with organic solvents is interesting area, and it is significant in science and valuable for application. This thesis primarily investigated the transport mechanism of nanofiltration membranes with organic solvents by micro and macro-methods. Using atomic force microscopy (AFM), studies showed their surface morphology in organic solvents. Moreover by macro-experiment, influences of conditions on transport flux of organic solvents permeating through nanofiltration membranes and rejection of the solute in organic solutions are also studied. Based on above experimental <WP=6>results, this thesis established experimental model and will provide theories for development and application of nanofiltration membranes.First of all, the stability of membranes in aqueous and organic solvents is reported. It was found that their surface morphology is obviously changed in organic solvents using atomic force microscopy (AFM). By observing flux of solvents and rejection of solute permeating through nanofiltration membranes, the results showed that flux of solvent permeating NF-SH membrane is significantly affected by membrane surface morphology, however, solvent properties mainly influence on flux of solvent permeating MPF-44 membrane. Rejections for the membranes (NF–SH, MPF–44) in organic systems are far lower than aqueous systems owing to interactions of solute-solvent.Secondly, by observing influences of pressure on transport flux of solvents permeating through nanofiltration membranes (NF-SH, Desal-DK, Les-90) and rejections in methanol solution with Brilliant Blue-G, studies showed that membrane compacting effect in methanol are more than water; in the methanol solution, a rise from 0.5Mpa to 1.5Mpa in pressure decreased rejections from 48.5% to 11.1%, which is different with result of the water solution (increased value of R=12.4%). By observing influences of temperature on the flux and rejection of the solute, studies testified the applicability of the Hagen－Poiseuille model in organic solvents and showed that a rise from 10℃ to 40℃ in temperature also decreased <WP=7>rejections from 31.3% to 19.7% in the methanol solution, however this result is the same as the one in the water solution (decreased value of R=13.0%). By observing influences of concentration of solute in the methanol solution on rejections, results showed that in the condition of higher pressure or temperature, concentration of solute slightly effects on rejections. Additional experiment studies the flux of some pure organic solvents and their organic solutions, results showed that due to reflect coefficient of organic solvent is far lesser than aqueous systems, when organic solvents are added with the solute, their fluxes are not changed greatly. Finally, by investigating the effects of solvent viscosity, molecular volume and solubility parameter on pure solvent permeability coefficient, studies established experimental model of pure solvent permeability coefficient and these parameters. The results showed that permeating hydrophilic membranes, the model of homogeneous and unhomogeneous solvents is A∝δ2/ Vmμ; and permeating hydrophobic membranes, the model of the above solvents is A∝1/ Vmμδ2.更多还原