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

Abstract

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 Hg0 from smelting flue gas. Benefiting from Se doping, the Hg0 capture performance of prepared FeSxSey is significantly enhanced compared with traditional iron sulfide, especially at high temperatures. Considering the recyclability and working temperature, FeS1.32Se0.11 exhibits the best Hg0 capture performance. The average capture rate of FeS1.32Se0.11 is 3.661 μg/g/min at 80 °C and its saturation adsorption capacity is 20.216 mg/g. The flue gas compositions have almost no effect on Hg0 capture. X-ray photoelectron spectroscopy and mercury thermal programmed desorption suggest that the stable active Se-Sn2- adsorption site can combine with Hg0 to form HgSe, consequently improving Hg0 capture performance at high temperatures. After Hg0 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 Hg0 capture performance, wide operating temperature range, and remarkable recycling property, FeSxSey microparticles may be a promising sorbent for Hg0 capture in industrial applications, while opening a new avenue to realize the resource utilization toward toxic elements.