Ion-exchange chromatography has been widely used as a standard process in purification and analysis of protein, based on the electrostatic interaction between the protein and the stationary phase. Through the years, several approaches are used to improve the thermodynamic description of colloidal particle-surface interaction systems, however there are still a lot of gaps specifically when describing the behavior of protein adsorption. Here, we present an improved methodology for predicting the adsorption equilibrium constant by solving the modified Poisson-Boltzmann (PB) equation in bispherical coordinates. By including dispersion interactions between ions and protein, and between ions and surface, the modified PB equation used can describe the Hofmeister effects. We solve the modified Poisson-Boltzmann equation to calculate the protein-surface potential of mean force, treated as spherical colloid-plate system, as a function of process variables. From the potential of mean force, the Henry constants of adsorption, for different proteins and surfaces, are calculated as a function of pH, salt concentration, salt type, and temperature. The obtained Henry constants are compared with experimental data for several isotherms showing excellent agreement. We have also performed a sensitivity analysis to verify the behavior of different kind of salts and the Hofmeister effects.

基于蛋白质和固定相之间的静电相互作用，离子交换色谱法已广泛用作蛋白质纯化和分析的标准方法。多年来，人们采用了几种方法来改善胶体颗粒-表面相互作用系统的热力学描述，但是在描述蛋白质吸附行为时，仍然存在很多空白。在这里，我们提出了一种改进的方法，用于通过在双球坐标系中求解修正的Poisson-Boltzmann（PB）方程来预测吸附平衡常数。通过包括离子与蛋白质之间以及离子与表面之间的色散相互作用，所使用的修改后的PB方程可以描述霍夫迈斯特效应。我们解决了改进的Poisson-Boltzmann方程，以计算作为过程变量函数的平均力的蛋白质表面势（被视为球形胶体板系统）。根据平均力的潜力，可以计算出不同蛋白质和表面的吸附亨利常数，该常数是pH，盐浓度，盐类型和温度的函数。将获得的亨利常数与几个等温线的实验数据进行比较，显示出极好的一致性。我们还进行了敏感性分析，以验证不同种类的盐的行为和霍夫迈斯特效应。盐浓度，盐类型和温度。将获得的亨利常数与几个等温线的实验数据进行比较，显示出极好的一致性。我们还进行了敏感性分析，以验证不同种类的盐的行为和霍夫迈斯特效应。盐浓度，盐类型和温度。将获得的亨利常数与几个等温线的实验数据进行比较，显示出极好的一致性。我们还进行了敏感性分析，以验证不同种类的盐的行为和霍夫迈斯特效应。