A Comparative Study on the Formation of Environmentally Persistent Free Radicals (EPFRs) on Hematite and Goethite: Contribution of Various Catechol Degradation Byproducts

• DOI: 10.1021/acs.est.9b04444
• Publication Date: 2019-11-04T18:48:50Z
• Authors: Peng Yi; Quan Chen; Hao Li; Di Lang; Qing Zhao; Bo Pan; Baoshan Xing
• Keywords: Catechol; Degradation

The formation and occurrence of environmentally persistent free radicals (EPFRs) have recently attracted increasing research attention. interactions between organics transition metals the crystalline forms are essential for EPFR formation. This study is thus designed to investigate catechol degradation compare characteristics EPFRs on α-Fe2O3 (hematite, HM) α-FeOOH (goethite, GT). Catechol was inhibited in dark presence iron oxides. inhibition stronger GT-silica, but electron paramagnetic resonance (EPR) signals two systems were comparable. enhanced under UV light irradiation comparable HM-silica EPR GT-silica. adsorbed HM a mononuclear bidentate (M-B) configuration, it both monodentate (M-M) binuclear (B-B) configurations GT. After series analysis, we proposed that dimer-type radical (2,2′,3,3′-tetrahydroxy-1,1′-biphenylene) responsible more stable system, while M-M structure favorable stabilization. Note analysis mechanisms, important consider (1) different lattices (2) contribution byproducts parent organics.