Efficient transformation of DDT with peroxymonosulfate activation by different crystallographic MnO2

Jingliang Liu; Fengxia An; Changyin Zhu; Dongmei Zhou

doi:10.1016/j.scitotenv.2020.142864

Efficient transformation of DDT with peroxymonosulfate activation by different crystallographic MnO₂

Sci Total Environ. 2021 Mar 10:759:142864. doi: 10.1016/j.scitotenv.2020.142864. Epub 2020 Oct 9.

Authors

Jingliang Liu¹, Fengxia An², Changyin Zhu³, Dongmei Zhou⁴

Affiliations

¹ School of Environmental Science, Nanjing XiaoZhuang University, Nanjing 211171, China.
² State Power Environmental Protection Research Institute Co. Ltd., Nanjing 210031, China.
³ School of the Environment, Nanjing University, Nanjing 210093, China.
⁴ School of the Environment, Nanjing University, Nanjing 210093, China. Electronic address: dmzhou@nju.edu.cn.

PMID: 33268252
DOI: 10.1016/j.scitotenv.2020.142864

Abstract

In this study, three different structures of MnO₂ were synthesized and used to activate peroxymonosulfate (PMS) for the degradation of DDT in aqueous solutions. It was found that DDT was efficiently degraded in the MnO₂/PMS system and the degradation rate was dependent on the properties of MnO₂ including crystal structure (followed the order: α-MnO₂ > γ-MnO₂ > β-MnO₂), surface area and Mn(III) content. Sulfate radicals (SO₄^-) was primarily responsible for the degradation of DDT based on the results of electron paramagnetic resonance (EPR) and quenching experiments. The degradation of DDT was suppressed at alkaline pH because the formation of SO₄^- was inhibited. The results of GC-MS indicated that dichlorobenzophenone, 4-chlorobenzoic acid and benzylalcohol were the dominant intermediates for DDT degradation. The possible pathways of DDT degradation were proposed according to the identified products.

Keywords: Activation; DDT degradation; Free radicals; Manganese oxides; Peroxymonosulfate.