ION-EXCHANGE EQUILIBRIA OF HEAVY-METALS ONTO CHEMICALLY MODIFIED APPLE RESIDUES

Apple residues (AR) from the cider-making process have been used as a cheap alternative ion exchange polymeric material. These residues were chemically modified in order to increase stability and ion exchange capacity. The ion exchange equilibria of copper, zinc and nickel onto the original residues (AR) as well as onto residues submitted to xanthation and phosphatation reactions have been studied. The experimental data fit the Langmuir equation adequately; saturation capacities, distribution constants and separation factors have been calculated.