Performance and mechanism of diatomite-loaded α-MnO2 nanocomposites for catalytic ozone oxidation of bromamine acid sodium salt
MnO2 with four types of crystalline phase structure and the composite nanomaterials of these MnO2 loaded on diatomite were successfully synthesized by a hydrothermal method,and a detailed research was conducted on their performance in catalytic ozonation and degradation of bromamine acid sodium salt(BAA).The materials were characterized by XRD,SEM,CV and EIS,of which α-MnO2/DE presented the lower polarization resistance and the faster electron transfer efficiency,which contributed to its excellent performance.Single factor experiments showed that the α-MnO2/DE-catalyzed ozone oxidation system could degrade 50 mg·L-1 BAA by 100％within 30 min.XPS characterization before and after the reaction,free radical quenching experiment,and ESR analysis was used to identify the catalytic mechanism of the system.The results showed that Mn(Ⅲ)acted as the reactive site to adsorb O3 molecules and activate them to produce ROS,at the same time the main reactive oxygen species in the system was·OH.In addition,ionic interference and cycling experiments demonstrated that the novel catalyst had an excellent stability and promising application for organic pollutant degradation.
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