李存玉　刘莉成　金立阳　李红阳　彭国平

[摘要]该文采用纳滤分离低浓度乙醇中绿原酸，探索道南效应和溶解扩散效应对绿原酸分离的影响规律。实验表明溶液pH、乙醇浓度影响绿原酸分离行为，30%乙醇中绿原酸pH 3～7，截留率相差7027%，通过响应面法建立二次回归模型，纳滤膜截留相对分子质量、溶液pH、乙醇浓度存在交互作用，绿原酸存在状态决定了其分离行为，随着乙醇浓度的增加，游离态绿原酸因溶解扩散效应易吸附溶解在膜表面而促进其透过，解离态绿原酸在道南效应和溶解扩散效应的双重作用下，难以进入膜表面，而截留率显著升高。优选出的纳滤富集工艺相较于传统减压浓缩优势明显，解决了中药分离精制过程中，低浓度有机试剂环境中中药成分在溶剂回收时存在效率低下、成分损失严重的技术难题。

[关键词]绿原酸； 纳滤； 乙醇，道南效应； 溶解扩散效应

[Abstract]To separate chlorogenic acid from low concentration ethanol and explore the influence of Donnan effect and solutiondiffusion effect on the nanofiltration separation rule The experiment showed that solution pH and ethanol volume percent had influences on the separation of chlorogenic acid Within the pH values from 3 to 7 for chlorogenic acid in 30% ethanol， the rejection rate of chlorogenic acid was changed by 7027% Through the response surface method for quadratic regression model， an interaction had been found in molecule weight cutoff， pH and ethanol volume percent In fixed nanofiltration apparatus， the existence states of chlorogenic acid determinedits separation rules With the increase of ethanol concentration， the free form chlorogenic acid was easily adsorbed， dissolved on membrane surface and then caused high transmittance due to the solutiondiffusion effect However， at the same time， due to the double effects of Donnan effect and solutiondiffusion effect， the ionic state of chlorogenic acid was hard to be adsorbed in membrane surface and thus caused high rejection rate The combination of BoxBehnken design and response surface analysis can well optimize the concentrate process by nanofiltration， and the results showed that nanofiltration had several big advantages over the traditional vacuum concentrate technology， meanwhile， and solved the problems of low efficiency and serious component lossesin the Chinese medicines separation process for low concentration organic solventwater solution

[Key words]chlorogenic acid； nanofiltration； ethanol； Donnan effect； solutiondiffusion effect

中藥分离精制过程中，含有低浓度有机试剂的中间体在溶剂回收时存在效率低下、成分损失严重的技术难题。如柱色谱分离时采用不同浓度有机溶剂洗脱，洗脱液中有机溶剂浓度偏低时需要高温回收溶剂，对富含酚酸等热敏性成分具有破坏，且难以控制成分转化而影响分离效率，目前尚未出现适用可行的技术手段 [1]。纳滤是膜分离技术中的一种，截留相对分子质量在100～1 000，具有分离过程可常温操作，无热效应，能耗低等技术优势[2]，在热敏性中药成分分离精制领域具有独特优势[3]。……