Adsorption is a process in which heavy metals are adsorbed on
the solid surface, and the equilibrium is established when the
concentrations of heavy metal adsorbed and in water become
constant [34]. Adsorption isotherm is occurred when the
relationship between amounts of heavy metal ions adsorbed
and in water at equilibrium [35]. Many adsorption parameters can
be calculated from these isotherms. Langmuir and Freundlich
models are the models which are widely used in adsorption
isotherms.