Elemental Mercury Oxidation over Fe–Ti–Mn Spinel: Performance, Mechanism, and Reaction Kinetics

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• 作者：Shangchao Xiong ; Xin Xiao ; Nan Huang ; Hao Dang ; Yong Liao ; Sijie Zou ; Shijian Yang
• 刊名：Environmental Science & Technology
• 出版年：2017
• 出版时间：January 3, 2017
• 年：2017
• 卷：51
• 期：1
• 页码：531-539
• 全文大小：542K
• ISSN：1520-5851

文摘

The design of a high-performance catalyst for Hg⁰ oxidation and predicting the extent of Hg⁰ oxidation are both extremely limited due to the uncertainties of the reaction mechanism and the reaction kinetics. In this work, Fe–Ti–Mn spinel was developed as a high-performance catalyst for Hg⁰ oxidation, and the reaction mechanism and the reaction kinetics of Hg⁰ oxidation over Fe–Ti–Mn spinel were studied. The reaction orders of Hg⁰ oxidation over Fe–Ti–Mn spinel with respect to gaseous Hg⁰ concentration and gaseous HCl concentration were approximately 1 and 0, respectively. Therefore, Hg⁰ oxidation over Fe–Ti–Mn spinel mainly followed the Eley–Rideal mechanism (i.e., the reaction of gaseous Hg⁰ with adsorbed HCl), and the rate of Hg⁰ oxidation mainly depended on Cl^• concentration on the surface. As H₂O, SO₂, and NO not only inhibited Cl^• formation on the surface but also interfered with the interface reaction between gaseous Hg⁰ and Cl^• on the surface, Hg⁰ oxidation over Fe–Ti–Mn spinel was obviously inhibited in the presence of H₂O, SO₂, and NO. Furthermore, the extent of Hg⁰ oxidation over Fe–Ti–Mn spinel can be predicted according to the kinetic parameter k_E-R, and the predicted result was consistent with the experimental result.