Study on the removal of oxidized mercury (Hg2 +) from flue gas by thiol chelating resin

Abstract

Thiol chelating resin was first introduced to remove oxidized mercury (Hg2+) from flue gas, and it could avoid the mercury re-emission brought about by the wet flue gas desulfurization process. Thiol chelating resin is prepared with chloromethyl polystyrene resin as material, and then thiol chelating resin was characterized by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, elemental analysis, and thermogravimetric analysis. The Hg2+ adsorption performance of thiol chelating resin and its sorption behavior were also investigated in simulated flue gas containing Hg2+. It was found that thiol chelating resin possessed high thermal stability and specific surface area, and could be used as an adsorbent for Hg2+ removal from flue gas. The sorption behavior of Hg2+ from flue gas by thiol chelating resin conformed to pseudo second-order kinetics, and the chemisorption process was the rate-limiting step. The Hg2+ removal efficiency was above 90% for flue gas at 25–50°C. Thiol chelating resin captured Hg2+ was regenerated successfully by 6M hydrochloric acid. When thiol chelating resin has been regenerated three times, its regeneration rate still reached up to 90.2%. The reusability of thiol chelating resin made the Hg2+ removal process economically feasible.