Development of a modified Langmuir model for prediction of pH influence on adsorption processes

Analytical isotherm equations such as Langmuir and Freundlich are widely used for modeling adsorption process. However, these isotherms are primarily useful for simulating data collected at a fixed pH value and cannot be easily used to simulate pH-dependent adsorption data. Therefore, most adsorption processes studies currently use numerical surfacecomplexation models (SCMs), which are more complex and time consuming than traditional analytical isotherm models. In this study, a new analytical isotherm model is presented for simulation ofpH-dependent adsorption. This model was validated by predicting Ni adsorption reported in literature. Investigation shows that the average deviation of proposed adsorption prediction model with reported model in literature is about 13%. The proposed analytical isotherm can help to reduce numerical modeling complexity and computational calculations.