Hg reactions in the presence of chlorine species: Homogeneous gas phase and heterogeneous gas-solid phase

The kinetics of Hg chlorination (with HCI) was studied using a flow reactor system with an online Hg analyzer, and speciation sampling using a set of impingers. Kinetic parameters, such as reaction order (alpha), overall rate constant (k'), and activation energy (E-a), were estimated based on the simple overall reaction pathway. The reaction order with respect to C-Hg, k', and E-a were found to be 1.55, 5.07 x 10(-2)exp(-1939.68/T) [(mug/m(3))(-0.55)(s)(-1)] and 16.13 [kJ/mol], respectively. The effect of chlorine species (HCI, CH2Cl2) on the in situ Hg capture method previously developed(28) was also investigated. The efficiency of capture of Hg by this in situ method was higher than 98% in the presence of chlorine species. Furthermore, under certain conditions, the presence of chlorine enhanced the removal of elemental Hg by additional gas-phase oxidation.