Synthesis of cobalt ferrite nanoparticles from waste iron ore tailings and spent lithium ion batteries for photo/sono-catalytic degradation of Congo red

Abstract

Cobalt ferrite nanoparticles were successfully synthesized by a combined coprecipitation method using recovered iron and cobalt from waste iron ore tailing and spent lithium ion batteries, respectively, characterized and utilized for photo/sono-catalytic degradation of Congo red. Characterizations by powder XRD, UV-DRS, SEM/TEM and surface area measurement revealed the formation of single phase spinel-type structure with average size 40–50 nm, surface area (36.2 m2/g), saturation magnetization (63 emu/g) and band gap energy (1.61 eV). XPS results showed that iron and cobalt in CoFe2O4 are present as Fe3+ and Co2+. It efficiently degraded CR dye under visible light and ultrasonic power for which the most probable degradation pathways were proposed. Recyclability tests showed the magnetic catalyst is reasonably stable, efficient and easily separated using an external magnet. Moreover, the present work gives further insight towards possible use of solid wastes in synthesis of value added materials in large scale for environmental applications.