Removal of Elemental Mercury from Flue Gas by Thermally Activated Ammonium Persulfate in A Bubble Column Reactor

In this article, a novel technique on removal of elemental mercury (Hg-0) from flue gas by thermally activated ammonium persulfate ((NH4)(2)S2O8) has been developed for the first time. Some experiments were carried out in a bubble column reactor to evaluate the effects of process parameters on Hg-0 removal. The mechanism and kinetics of Hg-0 removal are also studied. The results show that the parameters, (NH4)(2)S2O8 concentration, activation temperature and solution pH, have significant impacts on Hg-0 removal. The parameters, Hg-0, SO2 and NO concentration, only have small effects on Hg-0 removal. Hg-0 is removed by oxidations of (NH4)(2)S2O8, sulfate and hydroxyl free radicals. When (NH4)(2)S2O8 concentration is more than 0.1 mol/L and solution pH is lower than 9.71, Hg-0 removal by thermally activated (NH4)(2)S2O8 meets a pseudo-first-order fast reaction with respect to Hg-0. However, when (NH4)(2)S2O8 concentration is less than 0.1 mol/L or solution pH is higher than 9.71, the removal process meets a moderate speed reaction with respect to Hg-0. The above results indicate that this technique is a feasible method for emission control of Hg-0 from flue gas.