School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, P. R. China.
Environ Sci Technol. 2021 May 18;55(10):7094-7101. doi: 10.1021/acs.est.1c01631. Epub 2021 May 6.
Capturing gaseous Hg using regenerable metal sulfides is a promising technology to recover gaseous Hg from both coal-fired flue gas (CFG) and smelting flue gas (SFG) for the centralized control. Gaseous Hg concentration in SFG is 2-3 orders of magnitude higher than that in CFG; therefore, the design strategy of metal sulfides for capturing gaseous Hg from CFG is quite different from that from SGF. In this work, the structure-activity relationship of metal sulfides to capture Hg was investigated according to the remarkable difference in MoO loading on sulfureted FeTiO to capture low/high concentrations of gaseous Hg. The rate of Hg adsorption onto metal sulfides was mainly related to the amounts of adsorption sites and S on the surface, the affinity of adsorption sites to gaseous Hg, and the gaseous Hg concentration. Meanwhile, the capacity for Hg adsorption was approximately equal to the less of the amount of adsorption sites and S on the surface. Furthermore, capturing low concentrations of gaseous Hg from CFG required the metal sulfide sorbents having more adsorption sites with strong affinity to gaseous Hg, while capturing high concentrations of gaseous Hg from SFG required the sorbents with enough adsorption sites.
采用可再生金属硫化物捕集气态汞是一种很有前途的技术，可以从燃煤烟道气（CFG）和冶炼烟道气（SFG）中集中回收气态汞。SFG 中的气态汞浓度比 CFG 高 2-3 个数量级；因此，用于从 CFG 中捕集气态汞的金属硫化物的设计策略与从 SGF 中捕集气态汞的设计策略有很大的不同。在这项工作中，根据硫化铁钛负载钼的显著差异，研究了金属硫化物捕集 Hg 的结构-活性关系，以捕集低/高浓度的气态 Hg。金属硫化物对 Hg 的吸附速率主要与表面上的吸附位和 S 的数量、吸附位对气态 Hg 的亲和力以及气态 Hg 的浓度有关。同时，Hg 的吸附容量大约等于表面上的吸附位和 S 的数量较少的一方。此外，从 CFG 中捕集低浓度的气态 Hg 需要具有更多吸附位和对气态 Hg 具有强亲和力的金属硫化物吸附剂，而从 SFG 中捕集高浓度的气态 Hg 则需要具有足够吸附位的吸附剂。
