Synergetic activation of peroxymonosulfate by MnO2-loaded β-FeOOH catalyst for enhanced degradation of organic pollutant in water

In this paper, manganese dioxide (MnO2) loaded iron oxyhydroxide (beta-FeOOH) was synthesized aiming to improve the catalytic performance of beta-FeOOH as peroxymonosulfate activator. The beta-FeOOH@MnO2, PMS system exhibited excellent performance and its reaction rate constant of Acid Orange 7 (AO7) degradation (0.0533 min(-1)) was approximately 2.3 times as that in beta-FeOOH/PMS system (0.0232 min(-1)). beta-FeOOH@MnO2 possessed superior properties as catalyst than beta-FeOOH, owing to the higher surface hydroxyl density with higher specific surface area, redox ability and electronic transmission rate. Moreover, on the basis of the analysis from FTIR and XPS, it was found that the redox reaction of Fe3+/Fe2+ and Mn4+/Mn3+ synergistically activated PMS as well as the generation of FeOH+ and MnOH2+ accelerated activating PMS in the beta-FeOOH@ MnO2/PMS system. Thus, MnO2 and FeOOH synergistically activated PMS to reactive oxygen species (ROS). And O-1(2), O-2 center dot(-) and OH center dot were identified as predominant ROS in the beta-FeOOH@MnO2 /PMS system on the basis of the result from quenching experiments and ESR. Asa result, TOC removal rate was increased up to 22.62%. Additionally, beta-FeOOH@MnO2 exhibited good stability with low iron dissolution and manganese dissolution. Generally, this study proposed that beta-FeOOH@MnO2 was an efficient and environmental catalyst as PMS activator for organic pollutant degradation in water. (C) 2019 Elsevier B.V. All rights reserved.