有机溶液环境下地黄中梓醇的纳滤分离机制研究

Study on the Nanofiltration Separation Mechanism of Catalpol of Rehmannia Glutinosa in Ethanol-Water Solution

目的研究地黄中梓醇在含乙醇水溶液中的纳滤分离机制。方法基于溶解-扩散效应、电荷效应及分子筛分理论,考察乙醇浓度对膜通量、截留率、溶胀系数的影响,进而拟合不同乙醇浓度下的梓醇传质系数,分析梓醇的纳滤分离机制。结果操作压力与膜通量存在线性关系,随着乙醇浓度升高膜通量出现衰减,膜溶胀系数绝对值升高,膜材质在乙醇的溶胀作用下引起孔径变小,梓醇截留率从50.14%升高至91.16%,传质系数从19.27×10^-6 m/s下降至9.72×10^-6 m/s。结论乙醇引起膜面溶胀并改变梓醇与膜材质和溶液之间的作用力,强化了电荷排斥效应,提升截留率升高,初步解明了梓醇在乙醇水溶液环境中纳滤分离机制,为含有机溶剂的中药提取液常温化精制提供理论和技术支撑。

OBJECTIVE To Study on the nanofiltration separation mechanism of catalpol of Rehmannia glutinosa in ethanol-water solution.METHODS Based on solution-diffusion effect,charge effect and molecular sieving in nanofiltration separation,the influence of ethanol concentration on membrane flux,rejection and swelling coefficient,the mass transfer coefficient of catalpol was fitted with series of ethanol concentration to analyze the nanofiltration separation mechanism.RESULTS The experiment showed that there was a linear relationship between operation pressure and membrane flux.Meanwhile,the membrane flux gradually decayed and the absolute value of swelling coefficient increased with the increase of ethanol concentration.The rejection of catalpol increased from 50.14%to 91.16%,and the mass transfer coefficient decreased from 19.27×10^-6 m/s to 9.72×10^-6 m/s with the swelling of pore diameter in ethanol-water solution.CONCLUSION The molecular interaction force among catalpol,membrane material and solution are changed by ethanol.The charge rejection effect between nanofiltration membrane and catalpol is strengthened with the swelling of pore diameter.The nanofiltration separation mechanism of catalpol is preliminarily clarified in ethanol-water solution,which provides theoretical and technical support for concentrating heat-sensitive traditional Chinese medicine ingredients from the organic solvent-water solution at normal temperature.