1. Research on the adsorption mechanism of As by Fe-bearing minerals in coal during high-temperature combustion.
- Author
-
Song, Guo-chang, Li, Zhong-wei, Yang, Xing-yu, and Song, Qiang
- Subjects
- *
COAL combustion , *FERRIC oxide , *ALUMINUM oxide , *ADSORPTION (Chemistry) , *COMBUSTION , *COAL - Abstract
As can be retained by Fe components in coal during high-temperature combustion, which is beneficial for reducing As emissions. In this study, high-temperature As adsorption experiments were carried out in a fixed-bed experimental system with As model compound and minerals. The adsorption amount of As was much higher when Fe 2 O 3 , SiO 2 , and Al 2 O 3 acted together than when they acted alone. As was mainly distributed in the Fe-Si-Al minerals generated by the reaction of the three oxides, for which the Fe 2 O 3 :SiO 2 :Al 2 O 3 mass ratio of 1:1:1 was the most favorable, and the maximum adsorption amount of As was 18.2 mg·g−1. Density functional theory calculations were carried out for the adsorption of As 2 O 3 by Fe 2 O 3 , SiO 2 , Al 2 O 3, and Fe 2 Al 4 Si 5 O 18. Fe 2 Al 4 Si 5 O 18 had the highest adsorption energy for As 2 O 3 , indicating the most stable adsorption. As 2 O 3 was adsorbed on the Fe and Si sites. The adsorption ability of the Fe site was strengthened in Fe 2 Al 4 Si 5 O 18 relative to that in Fe 2 O 3. The formation of Fe-O-Si and Fe-O-Al in the mineral promoted electron transfer from the adsorbent to As 2 O 3 molecule, thereby strengthening adsorption. These results can guide the optimization of coal blending methods and the modification of adsorbents to control As emissions in coal-fired systems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF