(186f) The Importance of Surface Volume Representation and a New Modified Parachor Model for Predicting Surface Compositions of Binary Liquid Mixtures

Differences in composition between the surface region and the bulk region for binary liquids can occur. This can be due to preferential adsorption, and such surface enrichment can influence mass and heat transport. In order to investigate surface enrichment, reliable methods for predicting surface compositions are needed. In this study, a new modified parachor model for predicting surface compositions of binary liquid mixtures is presented, which provides generally more accurate prediction for the surface composition. In contrast to other predictive models, a more ??realistic? surface volume representation is incorporated. This model is then utilized to predict the surface compositions of several binary systems, involving organic?aqueous, organic?organic and aneotropic mixtures. The surface compositions obtained are compared to those directly determined from experimental measurements. The results show that the present modified parachor model provides surface composition predictions which are equal to, and in some cases are better than, those provided by other models. In general, the results demonstrate the usefulness of including a ??real? surface volume approximation in the surface enrichment models [1].

[1] M. Tjahjono, M. Garland, Journal of Colloid and Interface Science 345 (2010) 528?537