Birnessite nanorod-mediated decomposition of methylene blue with common oxidants

Abstract

In this paper, the birnessite nanorods (BN) were synthesized by microwave-assisted hydrothermal method and was characterized by powder X-ray diffraction measurements (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), and surface area (BET) analyzer. These results confirm the formation of birnessite nanorods. The catalytic decomposition profile of methylene blue by birnessite nanorods was tested. The effect of oxidants peroxomonosulfate (PMS) and peroxodisulfate (PDS) was compared with hydrogen peroxide (H2O2). Among these oxidants, PDS exhibits a high degree of decomposition of more than 80 % mineralization, achieved in 4 h when compared to PMS and H2O2. The decomposition was examined using varying amount of catalyst, which showed the dye decomposition activity to be proportional to the amount of the catalyst. The powder XRD studies showed no changes in the structure of birnessite nanorods, implying that these reactions are surface controlled. © 2012 The Author(s).