Development of Recyclable Iron Sulfide/Selenide Microparticles with High Performance for Elemental Mercury Capture from Smelting Flue Gas over a Wide Temperature Range

Fast and effective removal of elemental mercury in a wide temperature range is critical for the smelting industry. In this work, a recyclable magnetic iron sulfide/selenide sorbent is developed to capture and recover Hg-0 from smelting flue gas. Benefiting from Se doping, the Hg-0 capture performance of prepared FeSxSey is significantly enhanced compared with traditional iron sulfide, especially at high temperatures. Considering the recyclability and working temperature, FeS1.32 Se-0.11 exhibits the best Hg-0 capture performance. The average capture rate of FeS1.32 Se-0.11 is 3.661 mu g/g/min at 80 degrees C and its saturation adsorption capacity is 20.216 mg/g. The flue gas compositions have almost no effect on Hg-0 capture. X-ray photoelectron spectroscopy and mercury thermal programmed desorption suggest that the stable active Se-S-n(2-) adsorption site combine with Hg-0 to form HgSe, consequently improving Hg-0 capture performance at high temperatures. After Hg-0 capture, the spent FeSxSey can be collected by magnetic separation and regenerated through selective extraction, which facilitates harmless treatment and resource reuse of mercury. With the advantages of excellent Hg-0 capture performance, wide operating temperature range, and remarkable recycling property, FeSxSey microparticles may be a promising sorbent for Hg-0 capture in industrial applications, while opening a new avenue to realize the resource utilization toward toxic elements.