基于传质模型分析三七总皂苷超滤界面层分布特征及影响规律

目的 基于传质模型，探索三七总皂苷（Panax notoginseng saponins，PNS）超滤膜界面层浓度分布特征及影响规律。方法 以PNS中4种指标性成分三七皂苷R₁（R₁）、人参皂苷Rg₁（Rg₁）、人参皂苷Rb₁（Rb₁）和人参皂苷Rd（Rd）为检测指标，收集膜通量与指标成分截留率，基于超滤分离系数与膜通量、溶质截留率的相关性，拟合界面层浓度幂函数方程。对比混合溶液、单体溶液、成分组合对指标性成分界面层浓度的影响规律，采用响应曲面法考察成分组合配比（Rg₁-Rd）、超滤膜截留相对分子质量、跨膜压力差对界面层浓度分布的影响规律，探讨超滤分离机制。结果 界面层浓度幂函数回归系数均大于0.95，指标性成分界面层浓度与溶质浓度、跨膜压力差呈正性相关，随着截留相对分子质量的增加，PNS的超滤过程以界面层过滤向溶液过滤分离逐步过渡，表现出界面分布趋向性人参三醇型皂苷＞人参二醇型皂苷，其中Rg₁可以抑制Rd进入界面层，从而影响其分离过程。结论 构建了皂苷类成分超滤界面层浓度计算方法，初步阐明了PNS界面层分布特征和影响规律。

Exploring ultrafiltration interfacial distribution characteristics and influence rules of Panax notoginseng saponins based on mass transfer model

Objective To explore the interfacial distribution characteristics and influence rules of Panax notoginseng saponins (PNS) in ultrafiltration based on mass transfer model. Methods In the experiment, notoginsenoside R₁ (R₁), ginsenoside Rg₁ (Rg₁), ginsenoside Rb₁ (Rb₁) and ginsenoside Rd (Rd) were selected as indexes for collecting the membrane flux and solute rejection rate. Based on the correlation of separation coefficient with membrane flux and solute rejection rate, the power function equation of interfacial concentration was fitted to analyze the effects of mixed solution, monomer solution and composition combination on the concentration of index component in interface layer. Response surface methodology was used to investigate the effects of composition ratio (Rg₁-Rd), molecular weight cut-off (MWCO) and trans-membrane pressure (TMP) difference on the interfacial concentration distribution of Rd, and then to explore the mechanism of ultrafiltration separation. Results The power function equation of interfacial concentration was set up successfully with the regression coefficients (R² > 0.95), and the interfacial concentration was positively correlated with solute concentration and TMP. With the increase of MWCO, the ultrafiltration process was transitioned from interface layer filtration to solution filtration, and the interfacial distribution tendency was panaxatriol ginsenosides > panaxadiol ginsenosides. Rg₁ could inhibit the entry of Rd into interface layer, thus affecting its separation process. Conclusion The analytical model of ultrafiltration interfacial concentration was established to clarify the distribution characteristics and influence rules of interfacial layer of PNS preliminary.