It can be seen that the equilibrium data for M(II) adsorption on
chitosan and its derivatives fit the Langmuir model [30], which
indicated that M(II) adsorption on the these adsorbents was a
monolayer adsorption process occurring at specific homogeneous
sites [32]. The Langmuir monolayer adsorption capacities (qmax)
and the Langmuir equilibrium constant kL values for chitosan were