Hi Kauthar,
The discussion in this thread may be helpful for your question.
In general pH and salt concentration dependence can be included by adding the [H+] or salt concentration as a component and using a binding model that supports having a mobile phase modifier. Currently, this can be done using the Multi Component Colloidal model and it looks like the Mobile Phase Modulator Langmuir model may work as well. This won’t work with the Multi Component Langmuir model because you can’t treat components as a mobile phase modifier.