A Comparative Study on the Formation of Environmentally Persistent Free Radicals (EPFRs) on Hematite and Goethite: Contribution of Various Catechol Degradation Byproducts
A Comparative Study on the Formation of Environmentally Persistent Free Radicals (EPFRs) on Hematite and Goethite: Contribution of Various Catechol Degradation Byproducts
复制标题
赤铁矿和针铁矿形成环境持久性自由基（EPFR）的比较研究：各种儿茶酚降解副产物的贡献
DOI：
10.1021/acs.est.9b04444
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发表时间：
2019
影响因子：
11.4
通讯作者：
Xing Baoshan
中科院分区：
文献类型：
--
作者：
Yi Peng;Chen Quan;Li Hao;Lang Di;Zhao Qing;Pan Bo;Xing Baoshan
The formation and occurrence of environmentally persistent free radicals (EPFRs) have recently attracted increasing research attention. The interactions between organics and transition metals and the crystalline forms of the transition metals are essential for EPFR formation. This study is thus designed to investigate catechol degradation and compare the characteristics of EPFRs on α-Fe2O3(hematite, HM) and α-FeOOH (goethite, GT). Catechol degradation was inhibited in the dark in the presence of iron oxides. The inhibition was stronger on GT-silica, but the electron paramagnetic resonance (EPR) signals of the two systems were comparable. The enhanced degradation under UV light irradiation was comparable between HM-silica and GT-silica, but the EPR signals were stronger on GT-silica. Catechol was adsorbed on HM in a mononuclear bidentate (M-B) configuration, but it was adsorbed in both mononuclear monodentate (M-M) and binuclear bidentate (B-B) configurations on GT. After series analysis, we proposed that the dimer-type radical (2,2′,3,3′-tetrahydroxy-1,1′-biphenylene) was responsible for the more stable EPR signals for the HM system, while the M-M structure was more favorable for the catechol stabilization. Note that in the analysis of EPFR formation mechanisms, it is important to consider (1) different crystalline lattices and (2) the contribution of the degradation byproducts of the parent organics.
