Efficient removal of tetrabromobisphenol A through persulfate activation by α-MnO2 nanofiber coated with graphene oxide

The development of efficient and environmentally friendly catalysts for activating persulfate is the focus of advanced oxidation treatment of organic contaminants. Manganese dioxide (MnO 2 ), which has a multivalent nature and is a low-toxic natural stock, has the ability to immediately oxidize pollutants. In order to further improve its catalytic performance, the α-MnO 2 nanofiber coated with graphene oxide (α-MnO 2 @GO) was prepared by one-step hydrothermal method, and worked as a peroxmonsulfate (PMS) activator for efficient degradation of tetrabromobisphenol A (TBBPA). The structure characterization results indicate that α-MnO 2 nanofibers are successfully encapsulated by graphene and assembled into a three-dimensional layered structure. The factors affecting the catalytic degradation of TBBPA by this catalyst are investigated in detail. Under optimal conditions, the highest removal ratio of TBBPA could reach 100% after treatment of 20 min by α-MnO 2 @GO/PMS system, and a good mineralization efficiency of up to 79.50% is obtained. Electron paramagnetic resonance detection combined with quenching experiments showed that sulfate radical and hydroxyl radical played a role in the degradation of TBBPA. Based on X-ray photoelectron spectroscopy and free radical scavenging experiments, the peroxmonsulfate activation mechanism by α-MnO 2 @GO was proposed. Finally, based on the discovered intermediates, two potential TBBPA degradation routes using this catalyst were suggested. This study not only provides a new strategy for improving the catalytic activity of MnO 2 but also sheds new insight into the application of eco-friendly natural stock for environmental remediation.