Adsorption-coupled Fenton type reduction of bromate in water by high-yield polymer-derived ceramic-supported...

Nano-zerovalent iron (nZVI) is a promising material for the removal of both organic and inorganic pollutants from contaminated water. This study investigates the potential of a novel composite of nZVI on a polymer-derived supporting ceramic (nZVI-PDC) synthesized via the liquid-phase reduction method for the simultaneous adsorption and Fenton-type reduction of bromate anion (BrO₃^-) in water. The nZVI nanoparticles were effectively anchored onto the PDC by impregnating high-yield carbon in a ferrous sulfate solution. The PDC facilitated the uniform dispersion of nZVI nanoparticles due to its multiple active sites distributed within mesocarbon cavities. The developed nZVI-PDC composite exhibited a high specific surface area of 837 m² g^-1 and an ordered mesoporous structure with a pore volume of 0.37 cm³ g^-1. As an adsorbent, the nZVI-PDC composite exhibited a maximum adsorption capacity (q_e) of 842 mg g^-1 and a partition coefficient (K_H) of 10.2 mg g^-1 μM^-1, as calculated by the pseudo-second-order model. As a catalyst, the composite demonstrated a reaction kinetic rate of 43.5 μmol g^-1 h^-1 within 6 h at pH 4, using a dosage of 60 mg L^-1 nZVI-PDC and a concentration of 0.8 mmol L^-1 H₂O₂. Comparatively, PDC exhibited a q_e of 408 mg g^-1, K_H of 1.67 mg g^-1 μM^-1, and a reaction rate of 20.8 μmol g^-1 h^-1, while nZVI showed a q_e of 456 mg g^-1, K_H of 2.30 mg g^-1 μM^-1, and a reaction rate of 27.2 μmol g^-1 h^-1. The modelling indicated that the nZVI-PDC composite followed pseudo-second-order kinetics. The remarkable removal efficiency of the nZVI-PDC composite was attributed to the synergistic effects between PDC and nZVI, where PDC facilitated charge transfer, promoting Fe²⁺ generation and the Fe³⁺/Fe²⁺ cycle. Overall, this work introduces a promising adsorption technology for the efficient removal of BrO₃^- from contaminated aqueous solutions, highlighting the significant potential of the nZVI-PDC composite in water purification applications.