School of Energy Science and Engineering, Central South University, Changsha 410083, China.
School of Hydraulic Engineering, Changsha University of Science and Technology, Changsha 410004, China.
J Hazard Mater. 2022 Feb 15;424(Pt A):127336. doi: 10.1016/j.jhazmat.2021.127336. Epub 2021 Sep 24.
Porous carbons derived from one-pot carbonization and activation of wood sawdust in a molten salt (LiCl-KCl) medium were employed for Hg removal. The carbons derived from molten salt carbonization (MSC) displayed much superior Hg removal performance comparing with the carbons derived from N pyrolysis method (NC). The best molar ratio of LiCl-KCl was 59:41, the optimal molten salt temperature was 700 °C, and the best mass ratio of wood sawdust to molten salt was 1:10. The MSC displayed good applicability at 50-125 °C. The saturation Hg adsorption capacity of MSC was about 7828.39 μg·g, far exceeding those for carbonaceous adsorbents reported in literatures. A Hg removal mechanism over MSC was proposed, i.e., the hierarchical porous structure accelerated mass transfer of Hg, and the CO groups served as electron acceptors from Hg atoms to form organic matter bonded mercury (Hg-OM). The molten salt could be easily separated from the mixture of MSC for recycling multiple times. Thus, molten salt carbonization method appears to be promising in one-pot carbonization and activation of biomass as efficient adsorbents for gaseous Hg.
由木屑在熔融盐（LiCl-KCl）介质中一步碳化和活化得到的多孔碳被用于去除汞。与由 N 热解方法（NC）得到的碳相比，由熔融盐碳化（MSC）得到的碳表现出更高的汞去除性能。LiCl-KCl 的最佳摩尔比为 59:41，最佳熔融盐温度为 700°C，木屑与熔融盐的最佳质量比为 1:10。MSC 在 50-125°C 具有良好的适用性。MSC 的饱和汞吸附容量约为 7828.39μg·g，远远超过文献中报道的碳质吸附剂的吸附容量。提出了 MSC 上汞去除的机理，即分级多孔结构加速了汞的传质，CO 基团作为电子受体从 Hg 原子接受电子形成有机结合汞（Hg-OM）。熔融盐可以很容易地从 MSC 混合物中分离出来，以便多次回收利用。因此，熔融盐碳化法似乎很有希望在一锅碳化和活化生物质方面取得进展，成为去除气态汞的高效吸附剂。
