Utility of newly modified chitosan in the removal of heavy metal ions from aqueous medium: ion selectivity, XPS and TGA

The purpose of this study is to evaluate the newly prepared modified chitosan, a new environmentally friendly adsorbent, in the field of wastewater treatment. Chitosan (CS) reacted with 3-chloro-2,4-pentanedione to give CS derivatives, CS-CPD. Modified CS with O–O and N–O chelating centres was treated with aqueous solution containing different metal ions to investigate its metal uptake and selectivity. The concentration of metal ions in aqueous solution was measured by inductively coupled plasma-optical emission spectrometry. The structure of the complex was identified by elemental analysis, infrared and solid-nuclear magnetic resonance. In addition, the chelating centres were determined by X-ray photoelectron spectroscopy. The morphology of the modified polymer and its metal complexes was studied to show a dramatic change in cases of the CS-CPD–Pb, CS-CPD–Hg, CS-CPD–Cr and CS-CPD–Co complexes.