SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2015, Vol. 23 ›› Issue (7): 1169-1177.DOI: 10.1016/j.cjche.2015.04.010

• 化工热力学 • 上一篇    下一篇

Modeling for mean ion activity coefficient of strong electrolyte system with new boundary conditions and ion-size parameters

Miyi Li1, Tao Fang2   

  1. 1 School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China;
    2 Beijing Institute of Aerospace Testing Technology, Beijing 100074, China
  • 收稿日期:2014-11-18 修回日期:2015-03-06 出版日期:2015-07-28 发布日期:2015-08-21
  • 通讯作者: Miyi Li
  • 基金资助:

    Supported by the National Natural Science Foundation of China (21206010).

Modeling for mean ion activity coefficient of strong electrolyte system with new boundary conditions and ion-size parameters

Miyi Li1, Tao Fang2   

  1. 1 School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China;
    2 Beijing Institute of Aerospace Testing Technology, Beijing 100074, China
  • Received:2014-11-18 Revised:2015-03-06 Online:2015-07-28 Published:2015-08-21
  • Contact: Miyi Li
  • Supported by:

    Supported by the National Natural Science Foundation of China (21206010).

摘要: A rigorous approach is proposed to model the mean ion activity coefficient for strong electrolyte systems using the Poisson-Boltzmann equation. An effective screening radius similar to the Debye decay length is introduced to define the local composition and new boundary conditions for the central ion. The crystallographic ion size is also considered in the activity coefficient expressions derived and non-electrostatic contributions are neglected. Themodel is presented for aqueous strong electrolytes and compared with the classical Debye-Hückel (DH) limiting lawfor dilute solutions. The radial distribution function is compared with the DH andMonte Carlo studies. Themean ion activity coefficients are calculated for 1:1 aqueous solutions containing strong electrolytes composed of alkali halides. The individual ion activity coefficients andmean ion activity coefficients in mixed solvents are predicted with the new equations.

关键词: Activity coefficient, Electrolyte, Ion size, Poisson-Boltzmann equation

Abstract: A rigorous approach is proposed to model the mean ion activity coefficient for strong electrolyte systems using the Poisson-Boltzmann equation. An effective screening radius similar to the Debye decay length is introduced to define the local composition and new boundary conditions for the central ion. The crystallographic ion size is also considered in the activity coefficient expressions derived and non-electrostatic contributions are neglected. Themodel is presented for aqueous strong electrolytes and compared with the classical Debye-Hückel (DH) limiting lawfor dilute solutions. The radial distribution function is compared with the DH andMonte Carlo studies. Themean ion activity coefficients are calculated for 1:1 aqueous solutions containing strong electrolytes composed of alkali halides. The individual ion activity coefficients andmean ion activity coefficients in mixed solvents are predicted with the new equations.

Key words: Activity coefficient, Electrolyte, Ion size, Poisson-Boltzmann equation