Effective removal of Cr (VI) from an aqueous solution using a carbon coated NiFe2O4 nano-adsorbent

Exploration of cubic ferrites for chromium removal is ongoing. Ferrites offer a promising avenue for chromium removal because of their unique properties, high surface area, magnetic recoverability, and potential for surface modifications to enhance adsorption capacities. Herein, the work highlights the synthesis of carbonaceous nickel ferrite (NiFe2O4/C) through an inert ambient pyrolysis process, where metal acetylacetonates are used as the sources of metal ions and carbon. The synthesized NiFe2O4/C was successfully characterized for its structure and morphology using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Field emission scanning electron microscopy (FESEM), Energy Dispersive X-ray analysis (EDX), Raman spectroscopy, Transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis. The study confirmed that, the size of nanostructure was of ∼29 nm, with a surface area of 56.925 m2/g, pore volume of 0.085 cc/g with type IV hysteresis loop. The regular spherical shape was observed through FESEM, and a carbon coating was evident and confirmed from TEM. Synthesized NiFe2O4/C was efficiently used for the Cr (VI) removal, it was found that at an equilibrium time of 60 min, nearly 85% of the chromium was removed using 0.01 g of adsorbent at native pH and efficiency was further improved by lowering the pH. The investigation further examined the isotherm and kinetics models. The material was regenerated for 5 cycles with a removal percentage of 57%. [Display omitted]