Synthetization of hybrid nanocellulose aerogels for the removal of heavy metal ions

Abstract

This study aims to explore heavy metal ion adsorbents with excellent removal performance. For this, chitosan and gelatin-based hydrogel beads (Hyb) were prepared and crosslinked with a nanocellulose structure using ammonium zirconium carbonate (AZC) and calcium chloride (Ca). The prepared hybrid aerogels, HybAZC and HybCa, were characterized by using various techniques to investigate their respective morphologies and functional groups for a better understanding of their capacity for heavy metal ion adsorption. Then, we systematically investigated the difference in removal and adsorption capacities of heavy metal ions for single and multiple ion cases using the prepared aerogels-HybAZC and HybCa. The tested heavy metal ions were Hg(II), Pb(II), Cd(II), and Cr(III) ions. For the adsorption systems with single ion (S-HybAZC and S-HybCa) cases, every single metal ionic solution was studied in the presence of the aerogels; but for the multiple ion (M-HybAZC and M-HybCa) adsorption systems, mixed metal ionic solutions with predetermined concentrations of four heavy metal ions were studied. In a single system using S-HybAZC and S-HybCa aerogels, the removal efficiencies of all metal ions except the Cd(II) ion (using S-HybCa) were calculated to be above 65%. In multiple systems, regardless of the quality or quantity of aerogels or metal ions, the removal efficiencies were calculated to be above 85%. Overall, results suggest the prepared aerogels HybAZC and HybCa can be employed as effective adsorbents for single and multiple systems. Thus, hybrid nanocellulose aerogels have great potential for practical applications in the removal of heavy metal ions.