The heavy metals used were prepared as synthetic samples at 10 mg/L of
Pb(NO3)2, Cd(NO3)2, and Cu(NO3)26H2O using primary standards. In preliminary experiments using
banana cortex, it was found that material with 1 mm of particle size showed higher retention capability
(up to12%) than the material with 2 mm of particle size. Considering these results, 1 mm particle size
material was used in further experiments with the other waste materials.