ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Fabrication of novel magnetic chitosan/graphene-oxide/metal oxide nanocomposite beads for Cr(VI) adsorption

Chrisanne Naicker, Nolwazi Nombona, and Werner E. van Zyl

University of KwaZulu-Natal, Durban, South Africa

E-mail: nolwazi.nombona@up.ac.za

Abstract: Composites containing magnetic chitosan chloride, graphene oxide and one of three different metal oxides (MnO₂, Al₂O₃ and SiO₂) were synthesised in the morphological form of beads and applied in removing Cr(VI) species in solution. The composites were successfully characterised using IR, XRD, TGA, DSC and SEM. Adsorption studies were carried out by varying pH, concentration, temperature and time. Maximum adsorptions of 78.2, 77.8 and 75.9 mg g⁻¹ for each composite bead occurred at pH 2 and at 298 K. Adsorption followed the Langmuir isotherm, with a pseudo-second-order kinetic model. Thermodynamic studies proved that adsorption occurred spontaneously with the process being exothermic. The Cr(VI) species were desorbed from the beads using NaOH and the beads could be regenerated over six cycles.

Keywords: Functionalization of polymers ; Adsorption ; Porous materials ; Recycling ; Morphology 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-019-00895-7

Chemical Papers 74 (2) 529–541 (2020)