Citrate modified ferrihydrite microstructures: facile synthesis, strong adsorption and excellent Fenton-like catalytic properties

Hierarchical citrate modified ferrihydrite microstructures (Fh1) with flower-like morphologies were successfully synthesized via a simple aqueous solution route without the addition of any organic solvent or surfactant. The obtained products were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), BET analyses, Fourier-transform IR spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The prepared citrate modified ferrihydrite microstructures (Fh1) exhibited superior adsorption abilities for removal of methylene blue (MB) and Cr(VI) ions from aqueous solution. In addition, these citrate modified ferrihydrite microstructures also exhibited high activity to produce hydroxyl radicals through catalytic decomposition of H2O2 and could degrade highly concentrated MB solution at neutral pH. The results indicate that citrate modified ferrihydrite microstructures are very promising adsorbents and (photo-) Fenton-like catalysts for the treatment of pollutants.