Supported nano-catalyst for oxidative degradation of organic pollutants

Abstract

Sulfate radical-based advanced oxidation technologies (SR-AOTs) are attracting attention due to the generation of very strong oxidizing species (sulfate radical) which are capable of decomposing recalcitrant organic molecules in aqueous environment. In the previous report, Co3O4/MgO catalyst synthesized using incipient wetness impregnation method was found the most effective in activation of oxone in the dark and thus the degradation of Methylene Blue was completed via heterogeneous pathway within 4 minutes. To further investigate the efficiency of Co3O4/MgO catalyst, six more dyes were tested and investigated in both acidic and neutral pH conditions. All the dyes were successfully degraded within a few minutes in the presence of oxone and catalyst without pH adjustment (acidic condition) and the performance of Co3O4/MgO catalyst was found better than the unsupported Co3O4 catalyst. However, the Co3O4/MgO catalyst exhibited short term stability and difficultly in removing and recovering after application, hence a novel magnetically separable Fe3O4-Co3O4/MgO catalyst was prepared. The Fe3O4-Co3O4/MgO catalyst showed significant improvement in heterogeneous oxone activation as all the dyes were degraded completely in 1 minute due the generation of additional sulfate radicals. In addition, the Fe3O4-Co3O4/MgO catalyst can be easily separated due to its ferromagnetic property and exhibited long term stability. It is believed that the Fe3O4-Co3O4/MgO/oxone system represents a promising advanced system in the degradation of organic pollutants for potential industrial applications.