The Effect of Anions on Mercury Re-emission from Wet Flue Gas Desulfurization Liquors

Hg²⁺ captured by wet flue gas desulfurization (WFGD) systems can easily be reduced by reducing substances such as S(IV) (SO₃^2- or HSO₃^2-) and results in elemental mercury (Hg⁰) emissions. So the mercury removal efficiency decreases because of Hg0 reemission. The effects of anions on the characteristics of Hg²⁺ reduction and Hg⁰ reemission were studied by bubble reactor in this paper. The experimental results indicate that the Hg0 re-emission rate from WFGD liquors increases with decreasing the SO₃^2-, Cl^-, F^-, NO₃^- and SO₄^2- concentration. So the Hg⁰ re-emission from WFGD system can be reduced or slowed by increasing the some anions concentration, such as SO₃3, Cl^-, F^-, NO₃^- and SO₄^2-. The investigations provide theoretical basis for industrial application of simultaneous mercury control in wet FGD systems.