等温模型在“液-液萃取”中的适用性探讨

Applicability of Isotherm Model in Liquid-Liquid Extraction

液-液萃取的核心问题是溶质在不互溶两相间的平衡浓度分布。对于绝大多数化学化工类理论和实验教学而言,呈线性分布特征的萃取体系往往被选为教学实例。而对于呈非线性分布特征的体系,因其受制于现有模型的复杂性,鲜少出现在教学中。笔者在教学研究中发现,诸多体系的非线性分布特征满足常规的等温模型,且分配系数可由确定的函数关系所表达。此外,萃取体系的模型适用性与该体系中溶质、溶剂和萃取剂3者间的相互作用机制密切相关。综上所述,本文将等温模型用于液-液萃取,解决了现有模型的复杂性问题,拓展了教学内容,可使学生深入理解萃取机理,并培养其科研思维能力。

Distribution of equilibrium concentration of solute between two immiscible phases is a core issue of liquid-liquid extraction.For most of theoretical and experimental courses in chemistry or chemical engineering,the extraction systems that showed the linear distribution were selected as teaching examples.However,the systems showing the non-linear distribution rarely occurred in teaching.This was because the current model applied in the systems mentioned above was quite complex.In the teaching research,we found that the common isotherm model can well describe the non-linear distribution of many systems,and that the distribution coefficient can be expressed by determined functional relationship as well.Further,we also found that the model applicability of extraction systems highly related to interaction mechanism among solute,solvent and extractant thereof.Above all,applying the isotherm model in the liquid-liquid extraction can solve the complexity issue of the current model,expand the teaching contents,help students better understand the extraction mechanism,and train them in scientific thinking.