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

Fu, Kang-Li, Yao, Ming-Yu, Qin, Chuan-guang, Cheng, Guang-Wen, Li, Yang, Cai, Ming, Yang, Song, Nie, Jian-Ping
Fuel processing technology 2016 v.148 pp. 28-34
Fourier transform infrared spectroscopy, adsorbents, adsorption, chelating agents, economic feasibility, flue gas, flue gas desulfurization, hydrochloric acid, mercury, polystyrenes, resins, surface area, thermal stability, thermogravimetry, thiols
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.