Activation of Peroxymonosulfate and Persulfate by Metal Loaded Mesoporous Catalysts for Orange G Dye Degradation

Abstract

The main objective of this research was to study the catalytic activation of two different oxidants (potassium persulfate, PS and peroxymonosulfate, PMS) employing sulfate-based Advanced Oxidation Processes (AOPs). For this purpose, heterogeneous copper and cobalt catalysts were synthesized supported on MCM-41 mesoporous material. These catalysts were characterized by means of Atomic Absorption Spectroscopy (AA), X-ray diffraction (XRD), and Transmission Electron Microscopy (TEM). The metal charge of the catalysts ranged from 5% to 18%. The mesoporous arrangement was held after the metal loading and calcination, as shown by XRD patterns and TEM micrographs. The catalytic degradation of Orange G azo dye (Orange G: OG, disodium 7-hydroxy-8-[(E)-phenyldiazenyl]-1,3-naphthalenedisulfonate) was analysed, and the catalyst activities were determined in a batch reactor. The combination of PMS and higher metal-content Co-supported catalyst attained the best efficiency. In these conditions, the complete decolourization (100%) of the dye was achieved in the first minutes of reaction, while its mineralization reached after 4 h was 49%. Additionally, the catalytic activity of the Co/PMS system (a measure of the catalyst’s reusability) remained constant after three cycles of usage.