Gram-grade Cr(vi) adsorption on magnetite/carbon hybrid architectures

Abstract

In this work, two-dimensional magnetite/carbon (Fe₃O₄@C) hybrid architectures were fabricated by a feasible template method via thermal treatment. The Fe₃O₄ nanoparticles were tightly embedded into the carbon sheets in the form of well-ordered arrays and disordered assembly. These architectures were then employed to remove Cr(VI) ions from water. Whatever the arrangement of Fe₃O₄ nanoparticles in the carbon sheets, the maximum Cr(VI) adsorption capacities were found to be around 1100 mg g⁻¹ above 308 K in the pH range of 4.84–5.83. These values, to our knowledge, were much larger than those reported for metal-oxide adsorbents and activated carbons in the previous literature. More strikingly, these adsorbents can be easily separated from water by using a magnet. The high Cr(VI) adsorption capacities at different temperatures and easy separation are highly promising for their widespread potential applications in water treatment.