Irradiation of Fe-Mn@SiO2 with microwave energy enhanced its Fenton-like catalytic activity for the degradation of methylene blue

The application of microwave energy in the synthesis of catalytic materials has been indicated to induce desirable effects that lead to improved activity. Herein, bimetallic oxides immobilised on silica were prepared by incipient-wetness impregnation method and the resulting catalysts were subjected to microwave irradiation. The catalysts were characterised with X-ray diffraction, X-ray photoelectron spectroscopy and cyclic voltammetry. A comparison of the activities of the catalyst thermally treated in microwave oven with that thermally treated in conventional oven showed that the former exhibited superior performance. Microwave power and duration of irradiation had influence on the crystallite size of the catalysts which in turn had effect on their activities for heterogeneous Fenton degradation of methylene blue in aqueous solution. It was also observed that Fe/Mn ratio in the catalyst significantly affected its activity. The bimetallic catalyst was highly effective for the destruction of the target organic pollutant, with 97% of the dye degraded in 60 min at near neutral pH when the optimised catalyst was used. The material can be an attractive heterogeneous catalyst for Fenton decontamination of water containing harmful organic substances. [GRAPHICS] .