Kinetics and mechanism study of H-acid degradation by peroxymonosulfate activation with Co3O4-Fe2O3/Al2O3

Alumina supported bimetallic cobalt-iron oxide (Co3O4-Fe2O3/Al2O3) catalyst was prepared via co-impregnation of boehmite with the mixture solution of cobalt nitrate and iron nitrate followed by calcination in air. X-ray photoelectron spectroscopy and high-resolution transmission electron microscope analyses confirmed the existence of highly dispersed Co3O4 and Fe2O3 nanoparticles in the as-prepared catalysts. The catalytic activity of Co3O4-Fe2O3/Al2O3 was evaluated for the degradation of H-acid in aqueous solution by heterogeneous activation of peroxymonosulfate. The results indicated that the Co3O4-Fe2O3/Al2O3 catalyst exhibited an identical initial activity but much better recyclability than Co3O4/Al2O3 due to its low amount of metal leaching and possible redox circle of Co(II)/Co(III). Electron paramagnetic resonance spectroscopy and radical quenching experiments suggested that singlet oxygen (O-1(2)) contributed much more than center dot OH and SO4 center dot to H-acid degradation, and the degradation mainly followed a nonradical reaction mechanism.