The use of banana peel which is waste in this study will be
environmental friendly and can adsorb cadmium ion from
aqueous solution. The banana peel material is a potential
candidate for biosorption and further studies will help to
evaluate economical use of this biosorbent. The biosorption was
dependent on particle size, solution pH and initial cadmium ion
concentration. The particle size of banana peel had no influence
on the removal of cadmium ions. As the pH of around 5, the
cadmium ion removal leveled off at a maximum value. The
Langmuir and Freundlich isotherms did not fit the experimental
data. The experimental data displayed an unusual S-shaped
isotherms. FT-IR spectroscopy revealed that carboxyl, hydroxyl
and amide groups on the banana peel surface were involved in
the biosorption of the cadmium ions.