Elemental Mercury Capture from Flue Gas by a Supported Ionic Liquid Phase Adsorbent

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• 作者：Xiaoshan Li ; Liqi ZhangDong Zhou ; Wenqian Liu ; Xinyang Zhu ; Yongqing Xu ; Ying Zheng ; Chuguang Zheng
• 刊名：Energy & Fuels
• 出版年：2017
• 出版时间：January 19, 2017
• 年：2017
• 卷：31
• 期：1
• 页码：714-723
• 全文大小：576K
• ISSN：1520-5029

文摘

As promising functional materials, ionic liquids have been widely used in flue gas purification and separation. Previous studies reported that ionic liquid based mixtures can be used for mercury removal due to their high economic efficiency and environmental friendliness. In comparison with ionic liquid based mixtures, a supported ionic liquid phase (SILP) adsorbent shows significantly improved mercury removal performance because of its greatly enhanced gas/liquid interfacial area. In this study, a novel supported task-specific ionic liquid phase adsorbent [C₄mim][FeCl₄]–SiO₂ was prepared for high efficiency elemental mercury capture from flue gas. The Hg⁰ removal performance was investigated in a bench-scale fixed bed reactor, and the reaction mechanism was proposed based on the temperature programmed desorption (TPD) test. The results showed that Hg⁰ removal was mainly due to the oxidation by [C₄mim][FeCl₄]. The addition of [C₄mim][FeCl₄] on SiO₂ in a certain composition range enhanced the Hg⁰ removal performance, and the optimized ionic liquid loading is 30%. The Hg⁰ removal by the adsorbent was favored at higher temperatures. TPD results showed that the mercury compound formed on the adsorbent was HgCl₂. The Hg⁰ removal mechanism involves combined physisorption and chemisorption, which consists of Hg⁰ oxidation to HgCl₂ by the ionic liquid and physical adsorption of HgCl₂ on the porous adsorbent.