Activation of Oxone® with plasma deposited mixed cobalt and alumina oxide for the dye degradation

Abstract

The aim of this work is to examine the possibility of the formation of cobalt doped Al2O3 coatings on aluminum substrate by plasma electrolytic oxidation process (PEO) and application of the obtained material as catalyst in the sulfate radical (SO4−) based advanced oxidation process (SR-AOP). The morphology and elemental composition, of the coatings were characterized using Scanning Electron Microscopy. The obtained material was tested as catalyst in SR-AOP in the degradation of model dye (tartrazine) in aqueous solution. Potassium peroxymonosulfate (Oxone®) was used as the source of radicals. The catalytic role of cobalt in tartrazine decolorization was tested in the catalytic system consisting of PEO cobalt doped Al2O3 coated Al plates and Oxone®. It was found that the addition of cobalt precursor into PEO electrolyte solution significantly improved the catalytic properties of obtained coatings with respect to cobalt-free Al2O3 coating and Oxone®. The influence of cobalt content in the supporting electrolyte during PEO process on the catalytic activity of the coatings, as well as Oxone® dosages in SR-AOP, were examined.