Highly Dispersed Mn–Ce Binary Metal Oxides Supported on Carbon Nanofibers for Hg<sup>0</sup> Removal from Coal-Fired Flue Gas
Highly dispersed Mn⁻Ce binary metal oxides supported on carbon nanofibers (MnO<sub>x</sub>⁻CeO<sub>2</sub>/CNFs(OX)) were prepared for Hg<sup>0</sup> removal from coal-fired flue gas. The loading value of the well-dispersed MnO<sub>x</...
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MDPI AG
2018-12-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/8/12/2501 |
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| author | Yongjun Xia Zhiqiang Liao Yan Zheng Zijian Zhou |
| author_facet | Yongjun Xia Zhiqiang Liao Yan Zheng Zijian Zhou |
| author_sort | Yongjun Xia |
| collection | DOAJ |
| description | Highly dispersed Mn⁻Ce binary metal oxides supported on carbon nanofibers (MnO<sub>x</sub>⁻CeO<sub>2</sub>/CNFs(OX)) were prepared for Hg<sup>0</sup> removal from coal-fired flue gas. The loading value of the well-dispersed MnO<sub>x</sub>⁻CeO<sub>2</sub> was much higher than those of many other reported supports, indicating that more active sites were loaded on the carbon nanofibers. In the present study, 30 wt % metal oxides (15 wt % MnO<sub>x</sub> and 15 wt % CeO<sub>2</sub>) were successfully deposited on the carbon nanofibers, and the sorbent yielded the highest Hg<sup>0</sup> removal efficiency (>90%) within 120⁻220 °C under a N<sub>2</sub>/O<sub>2</sub> atmosphere. An increase in the amount of highly dispersed metal oxides provided abundant active species for efficient Hg<sup>0</sup> removal, such as active oxygen species and Mn<sup>4+</sup> cations. Meanwhile, the carbon nanofiber framework provides the pathway for charge transfer during the heterogeneous Hg<sup>0</sup> capture reaction processes. Under a N<sub>2</sub>+6%O<sub>2</sub> atmosphere, a majority of Hg<sup>0</sup> was removed via chemisorption reactions. The effects of flue gas composition were also investigated. O<sub>2</sub> replenished the active oxygen species on the surface and thus greatly promoted the Hg<sup>0</sup> removal efficiency. SO<sub>2</sub> had an inhibitory effect on Hg<sup>0</sup> removal, but NO facilitated Hg<sup>0</sup> capture performance. Overall, carbon nanofibers seems to be a good candidate for the support and MnO<sub>x</sub>⁻CeO<sub>2</sub>/CNFs(OX) may be promising for Hg<sup>0</sup> removal from coal-fired flue gas. |
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| spelling | doaj.art-c8a29282e4b5476fa6d9f74ec22853af2022-12-21T21:52:11ZengMDPI AGApplied Sciences2076-34172018-12-01812250110.3390/app8122501app8122501Highly Dispersed Mn–Ce Binary Metal Oxides Supported on Carbon Nanofibers for Hg<sup>0</sup> Removal from Coal-Fired Flue GasYongjun Xia0Zhiqiang Liao1Yan Zheng2Zijian Zhou3State Grid Jiangxi Electric Power Science Research Institute, Nanchang 330096, ChinaState Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, ChinaNanchang Institute of Technology, Nanchang 330099, ChinaState Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science & Technology, Wuhan 430074, ChinaHighly dispersed Mn⁻Ce binary metal oxides supported on carbon nanofibers (MnO<sub>x</sub>⁻CeO<sub>2</sub>/CNFs(OX)) were prepared for Hg<sup>0</sup> removal from coal-fired flue gas. The loading value of the well-dispersed MnO<sub>x</sub>⁻CeO<sub>2</sub> was much higher than those of many other reported supports, indicating that more active sites were loaded on the carbon nanofibers. In the present study, 30 wt % metal oxides (15 wt % MnO<sub>x</sub> and 15 wt % CeO<sub>2</sub>) were successfully deposited on the carbon nanofibers, and the sorbent yielded the highest Hg<sup>0</sup> removal efficiency (>90%) within 120⁻220 °C under a N<sub>2</sub>/O<sub>2</sub> atmosphere. An increase in the amount of highly dispersed metal oxides provided abundant active species for efficient Hg<sup>0</sup> removal, such as active oxygen species and Mn<sup>4+</sup> cations. Meanwhile, the carbon nanofiber framework provides the pathway for charge transfer during the heterogeneous Hg<sup>0</sup> capture reaction processes. Under a N<sub>2</sub>+6%O<sub>2</sub> atmosphere, a majority of Hg<sup>0</sup> was removed via chemisorption reactions. The effects of flue gas composition were also investigated. O<sub>2</sub> replenished the active oxygen species on the surface and thus greatly promoted the Hg<sup>0</sup> removal efficiency. SO<sub>2</sub> had an inhibitory effect on Hg<sup>0</sup> removal, but NO facilitated Hg<sup>0</sup> capture performance. Overall, carbon nanofibers seems to be a good candidate for the support and MnO<sub>x</sub>⁻CeO<sub>2</sub>/CNFs(OX) may be promising for Hg<sup>0</sup> removal from coal-fired flue gas.https://www.mdpi.com/2076-3417/8/12/2501coal-fired flue gasmercurycarbon nanofibersmetal oxidesadsorption |
| spellingShingle | Yongjun Xia Zhiqiang Liao Yan Zheng Zijian Zhou Highly Dispersed Mn–Ce Binary Metal Oxides Supported on Carbon Nanofibers for Hg<sup>0</sup> Removal from Coal-Fired Flue Gas Applied Sciences coal-fired flue gas mercury carbon nanofibers metal oxides adsorption |
| title | Highly Dispersed Mn–Ce Binary Metal Oxides Supported on Carbon Nanofibers for Hg<sup>0</sup> Removal from Coal-Fired Flue Gas |
| title_full | Highly Dispersed Mn–Ce Binary Metal Oxides Supported on Carbon Nanofibers for Hg<sup>0</sup> Removal from Coal-Fired Flue Gas |
| title_fullStr | Highly Dispersed Mn–Ce Binary Metal Oxides Supported on Carbon Nanofibers for Hg<sup>0</sup> Removal from Coal-Fired Flue Gas |
| title_full_unstemmed | Highly Dispersed Mn–Ce Binary Metal Oxides Supported on Carbon Nanofibers for Hg<sup>0</sup> Removal from Coal-Fired Flue Gas |
| title_short | Highly Dispersed Mn–Ce Binary Metal Oxides Supported on Carbon Nanofibers for Hg<sup>0</sup> Removal from Coal-Fired Flue Gas |
| title_sort | highly dispersed mn ce binary metal oxides supported on carbon nanofibers for hg sup 0 sup removal from coal fired flue gas |
| topic | coal-fired flue gas mercury carbon nanofibers metal oxides adsorption |
| url | https://www.mdpi.com/2076-3417/8/12/2501 |
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