Synthesis of magnetic nickel ferrites nanocomposites: An advanced remediation of electroplating wastewater

Abstract

Nickel ferrite nanocomposites (NFNCs) were prepared and utilized to remove hexavalent chromium from the effluent of the electroplating industry. The nickel ferrite nanoparticles (NFNPs) were synthesized by the sol-gel auto combustion process, and they were doped ultrasonically onto the surface-modified multi-walled carbon nanotubes (SM-MWCNTs). Characterization results confirmed that the NFNPs with a cubic spinel structure were successfully impregnated onto the SM-MWCNTs. The synthesized NFNCs were tubular structures with an outer diameter in the range of 30–40 nm and had high crystal defect. The NFNCs with the surface area of 210.5 m2 g−1 offer high magnetic separability due to their paramagnetic behavior. Non-linear kinetic, thermodynamic, and isotherm models were used for interpretations, and high Cr(VI) uptake of 129.83 mg/g was obtained at 40 °C. The Cr(VI) uptake by NFNCs was dominated by electrostatic attractions at a low pH and ion exchange mechanism at a higher pH. Lastly, high efficient recyclability of the NFNCs and applicability in removing other heavy metals from electroplating effluent suggested them to be a promising material in wastewater treatment.