Gaseous Elemental Mercury Capture by Magnetic FeS2 Nanorods Synthesized via a Molten Salt Method.

Coal burning emits a significant amount of elemental mercury (Hg^o) into the atmosphere, which can cause severe damage to the environment and human health. Here, magnetic FeS₂ nanorods are facilely obtained via a low-temperature (200–350 °C) molten salt (KSCN) route. The annealing temperature is found to notably affect the structure and Hg^o capture performance of FeS₂, while precursors exert subtle effects on the mercury adsorption performance. The Hg^o capture ability of FeS₂ first increases and then decreases with increasing annealing temperature. The highest magnetism (12 emu/g) and optimal mercury capture performance (Hg^o removal efficiency of 96.2%) are achieved over FeS₂ nanorods synthesized at 250 °C. This material shows superior performance in the temperature range of 60–180 °C owing to its rod-like structure with ample number of exposed adsorption sites. NO and SO₂ are found to only slightly intervene in the mercury removal process. Hg^o vapor first adsorbs on the FeS₂ surface via physical adsorption followed by conversion into mercury sulfide (HgS) and mercury oxide (HgO) by the oxidation of disulfide ions (S₂^2–) and chemisorbed oxygen (O*) species, respectively. [ABSTRACT FROM AUTHOR]