Effect of organic ligands on the removal of Pb(II), Ni(II) and Cd(II) by ‘waste’ Fe(III)/Cr(III) hydroxide

Adsorption of metal ions such as Pb(II), Ni(II) and Cd(II) onto ‘waste’ Fe(III)/Cr(III) hydroxide was studied both in the presence and absence of ligands such as ethylenediamine tetraacetic acid, citrate and acetate. All three ligands decreased the adsorption of Pb(II) in the pH range 3.5 to 8.5. Citrate and EDTA considerably decreased the adsorption of Ni(II) but acetate showed a slight increase in adsorption. Cadmium adsorption decreased significantly in the presence of acetate and citrate.