多元液体混合物表面张力和组成预测模型

A model for predicting the surface tension and composition of multicomponent liquid mixtures

模型预测多元液体混合物的表面张力和组成具有重要的理论意义和实用价值,但目前仍缺乏适用的热力学预测模型.本工作假设各活性组分在表面发生聚集吸附且其吸附相互独立,建立了多元体系的热力学吸附模型,称为“表面聚集吸附模型”,将表面组成和体相组成相关联;与扩展的Eberhart模型联合,采用二元体系的模型参数值预测多元体系的表面张力和组成.模型参数均具有明确的物理意义,且可通过线性拟合获得唯一值.采用6个三元液体混合物体系的表面张力数据对模型进行了验证,模型预测与实验结果具有良好的符合度,证明了其合理性.另外,采用本模型考察了三元体系表面组成随体相组成的变化,获得了表面吸附信息,加深了对液体混合物表面吸附行为的认识.

Model prediction of the surface tension and composition of multicomponent liquid mixtures has fundamenta and practical significance,but there is still a lack of feasible thermodynamic predictive models.In the current work,a thermodynamic adsorption model,called the “surface aggregation adsorption” (SAA) model,was developed for multicomponent liquid mixtures,based on the assumptions that the surface aggregation adsorption occurs and the adsorptions of various components are independent of each other.It relates the surface composition (?_(i,s)) with the bulk composition (?_(i,b)).By coupling with the extended Eberhart equation,the model can predict the surface tension (σ) and ?_(i,s)of multicomponent liquid mixtures using the model parameters of corresponding binary systems.Its parameters al have rigorous physical meaning,and,in particular,can be estimated by linear fitting to obtain unique values.The mode was examined using theσdata of six ternary mixtures,confirming its rationality and universality.In addition,the change of ?_(i,s)with ?_(i,b)for ternary systems was investigated using the model,obtaining information on surface adsorption,which deepens the understanding of the surface adsorption behavior of liquid mixtures.