THE HOMOGENEOUS GAS-PHASE REACTION OF MERCURY WITH OXYGEN, AND THE CORRESPONDING HETEROGENEOUS REACTIONS IN THE PRESENCE OF ACTIVATED CARBON AND FLY-ASH

A laboratory-scale stopped flow reactor was used to study the homogeneous gas phase reaction of elemental mercury with oxygen and the corresponding heterogeneous reaction in the presence of activated carbon and fly ash at different temperatures. No homogeneous gas phase reaction occurred during a reaction time of 1 hour in the temperature range 20-700 degrees C. An upper limit second order rate constant of 1.10(-23) cm(3) molec.(-1) s(-1) at 20 degrees C and 4.10(-23) cm(3) molec.(-1) s(-1) at 700 degrees C, was estimated. In the presence of activated carbon or fly ash, at temperatures of 100-300 degrees C, mercury loss increases with increasing oxygen concentration. The reaction rate has a maximum at 200-250 degrees C, and exhibits a half order oxygen dependence and a first order dependence with respect to mercury.