Studies on removal of Pb(II) and Cr(III) using graphene oxide based inverse spinel nickel ferrite nano-composite as sorbent

- The graphene oxide based porous magnetic inverse spinel NiFe2O4 (GONF) is synthesized.
- The techniques of XRD, FT-IR and XPS are used in the characterization of GONF.
- The study demonstrates the suitability of GONF as a potential sorbent for heavy metals.
- Sorption of Pb(II) and Cr(II) is a rate limiting pseudo-second-order reaction.
- Inner-sphere complexation of heavy metals onto GONF surface exhibits the chemisorptions.

Synthesis of a hybrid graphene oxide based inverse spinel nickel ferrite (GONF) nano-composite material and subsequent utilization in heavy metal removal from aqueous solution is described in the present study. The synthesized GONF was characterized using X-ray diffraction (XRD), Fourier transform-infrared resonance (FT-IR), and X-ray photoelectron (XPS) spectroscopies. The morphology, the surface area and pore volume of GONF were evaluated by scanning electron microscopy (SEM) and BET analysis, respectively. GONF was successfully used for the removal of Pb(II) and Cr(III) by batch adsorption techniques. Batch kinetics studies revealed that the sorption of Pb(II) and Cr(III) onto GONF was well described by a pseudo-second-order equation. The sorption equilibrium data of Pb(II) and Cr(III) was well tuned to the Langmuir isotherm model than the Freundlich and Temkin isotherm models. Hence, the sorption of Pb(II) and Cr(III) onto GONF occurred through monolayer chemisorptions on the homogeneous surface of GONF. The pH sorption results suggest that the sorption occurs through a complexed mechanism. The sorption of metal ions increased with increasing temperature, which is evident for an endothermic chemisorption by inner-sphere surface complexation. The overall obtained results demonstrated the GONF as an effective sorbent for Pb(II) and Cr(III) removal from wastewater.