Adsorption of heavy metal ions on virgin and chemically-modified lignocellulosic materials

Amidoximated wood sawdust (Am-WS) and wood flour (Am-WF) were prepared using the same procedure as described recently for amidoximated cellulose (Am-Cell). The modified supports thus obtained were characterized by IR, TGA and DSC methods. In comparison to the untreated material, such treatment led to a considerable increase in adsorption capacity towards heavy metal ions from aqueous solution. The quantity adsorbed increased with pH, initial metal ion concentration and immersion time. The formation of a 1:1 complex between the amidoxime group and Cu(II), Cr(III) and Cd(II) ions and a 2:1 complex with the Ni(II) ion was demonstrated by the adsorption limit values. Overall, Am-WS and Am-WF exhibited similar behaviour to Am-Cell and are suitable for the treatment of wastewaters containing heavy metal ions.