Analysis of equilibrium isothermal model: One form of equilibrium isotherm model namely
Saad isotherm model was employed in this study. The equilibrium parameters were estimated by
correlating the equilibrium equations with the data from equilibrium experiments using nonlinear
regression technique (i.e., fminsearch function from MATLAB). Hence, the equilibrium parameters
were utilized to describe the chromium and lead ions removal by Bentonite clay as an adsorbent
in a batch adsorber.