rGO/MnO2 nanowires for ultrasonic-combined Fenton assisted efficient degradation of Reactive Black 5

Abstract

Reduced graphene oxide (rGO) coated manganese dioxide (MnO2) nanowires (NWs) were prepared by the hydrothermal method. Raman spectra confirmed the presence of rGO and the Brunauer–Emmett–Teller surface area of rGO/MnO2 NWs was found to be 59.1 m2g−1. The physico-chemical properties of prepared catalysts for the degradation of Reactive Black 5 (RB5) dye were investigated. 84% of RB5 dye in hydrogen peroxide solution was successfully degraded using rGO/MnO2 NWs, while only 63% was successfully degraded with pristine α-MnO2 NWs in 60 min owing to the smaller crystallite size and large surface area. Further, the ultrasonic-combined Fenton process significantly enhanced the degradation rate to 95% of RB5 by the catalyst rGO/MnO2 NWs due to synergistic effects. The decomposition products identified using gas chromatography-mass spectrometry revealed a higher production rate of fragments in the ultrasonic-combined Fenton process. Therefore, rGO/MnO2 NWs with the ultrasonic-combined Fenton process is an efficient catalyst for the degradation of RB5, and may be used for environmental protection.