The RL values of the metal ion solutions (100 mg/L;Co) were calculated from the Langmuir adsorption isotherms(Eq. (4)). The RL results were found to be between 0 and 1,0.10 for Pb(II) and 0.40 for Cu(II).
Therefore, it was concluded that the biosorption of the metal ions onto the biosorbent was favorable and that the Langmuir biosorption isotherms were applicable to the biosorption process.
Conversely, the Freundlich isotherms were used to indicate the surface heterogeneity of the adsorbent.
The results of the Freundlich model were not able to describe the relationship between the amount of biosorbed metal ions and their equilibrium concentrations in solution.
The Temkin constant (B) specifies the heat of sorption, and the results