DFT and Experimental Study on the Mechanism of Elemental Mercury Capture in the Presence of HCl on α-Fe2O3(001)

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• 作者：Ting Liu ; Lucheng Xue ; Xin Guo ; Yu Huang ; Chuguang Zheng
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：May 3, 2016
• 年：2016
• 卷：50
• 期：9
• 页码：4863-4868
• 全文大小：450K
• 年卷期：0
• ISSN：1520-5851

文摘

To investigate the mechanism of Hg⁰ adsorption on the α-Fe₂O₃(001) surface in the presence of HCl, which is considered to be beneficial for Hg⁰ removal, theoretical calculations based on density functional theory as well as corresponding experiments are carried out. HCl adsorption is first performed on the α-Fe₂O₃(001) surface, and the Hg⁰ adsorption on HCl-adsorbed α-Fe₂O₃(001) surface is subsequently researched, demonstrating that HCl dissociates on the surface of α-Fe₂O₃, improving the Hg⁰ adsorption reactivity. With further chlorination of the α-Fe₂O₃(001) surface, FeCl₃ can be achieved and the adsorption energy of Hg⁰ on the FeCl₃ surface reaches −104.2 kJ/mol, representing strong chemisorption. Meanwhile, a group of designed experiments, including Hg⁰ adsorption on HCl-preadsorbed α-Fe₂O₃ as well as the coadsorption of both gaseous components, are respectively performed to explore the pathways of Hg⁰ transformation. Combining computational and experimental results together, the Eley–Rideal mechanism with HCl preadsorption can be determined. In addition, subsequent X-ray photoelectron spectroscopy analysis verifies the appearance of Cl species and oxidized mercury, exhibiting the consistency with experiments.