Vanadium as co-catalyst for exceptionally boosted Fenton and Fenton-like oxidation: Vanadium species mediated direct and indirect routes

In this study, vanadium powder (V) was employed as a cocatalyst to enhance the Fenton-like system. The V-Fe(III)/H2O2 system can rapidly produce hydroxyl radicals and completely oxidize chloramphenicol with exceptionally high stability for long-term operation. The low-valent vanadium sites on the surface during the stepwise oxidation of vanadium from V0 to V(IV) can donate electrons for direct H2O2 activation and indirect Fenton reaction by reducing Fe(III) to produce hydroxyl radicals. Meanwhile, density functional theory (DFT) calculation unveils that low-valent vanadium sites of vanadium can lengthen Fe-O bonds of FeOH2+ to elevate the oxidation potential of Fe(III) and promote Fe(III) reduction induced by H2O2. The self-cleaning effect of vanadium under acidic conditions can maintain reactive sites for sustainable electron donation and long-lasting enhanced Fenton oxidation. This study provides a novel enhanced Fenton oxidation for water remediation and the first mechanistic insights into the origins of V-based advanced oxidation technologies, it may also be beneficial to treat vanadium-contained wastewater.