Comparative adsorption of Cu (II), Hg (II), Co (II), and Ni (II) ions on novel magnetic chitosan/cellulose/laponite RD nanocomposite hydrogel

This study describes the synthesis of a novel meso/magnetic adsorbent based on chitosan nanocomposite hydrogel to remove heavy metal ions from aqueous solutions. The meso/magnetic nanocomposite hydrogel was designed from the blending of chitosan and cellulose bio-polysaccharides in the presence of magnetic Laponite RD (nanoclay) nanoparticles (Fe3O4/La). Fe3O4/La nanoparticles were obtained by the in-situ co-precipitation method. The nanocomposite hydrogel was characterised by FT-IR, XRD, VSM, TGA, TEM, FE-SEM, and BET techniques. Several important parameters influence the adsorption of Cu (II), Hg (II), Co (II), and Ni (II) ions in the aqueous solution such as contact time, pH, temperature, and effect of metal concentration with single and multi-metal systems were investigated systematically by batch experiments. Compared with the adsorption of other ions, adsorption of the Hg (II) ions on the chitosan/cellulose/laponite RD nanocomposite hydrogel was showed high selective and high-efficient. The adsorption process of Hg (II) ions has shown best correlated to the Langmuir isotherm and pseudo-second-order models, respectively. The maximum adsorption capacity of Hg (II) ions was 579.8 mg/g. The thermodynamic data showed that the adsorption process was spontaneous, favourable, and endothermic.