The mechanism of bound hydroxyl radical formation and degradation pathway of Acid Orange II in Fenton-like Co2+-HCO3 − system.

Highlights: [•] Co(II) in the Fenton-like Co2+-HCO3 − system can be easily oxidized to Co(III). [•] Reduction of Co(III) back to Co(II) is the rate-limiting step. [•] Bound hydroxyl radical is produced by the system. [•] The two C-N bonds in acid orange II are simultaneous cleaved. [•] The dye is decomposed into p-phenolsulfonic acid, 1,2-naphthaquinone and N2. [ABSTRACT FROM AUTHOR]