Both physisorptive and chemisorptive mechanisms play a role in
the adsorption of mercury. The present publication investigates the
influence of oxygen on the adsorption of Hg
0
by breakthrough
curve measurements and temperature-programmed desorption (TPD) experiments.
The presence of O
2
in the gas phase promotes chemisorption.
Because of slow adsorption mechanisms, no equilibrium capacities of
mercury chemisorption can be determined. For further investigations,
coupled adsorption and desorption experiments with concentration swing
adsorption and TPD experiments are performed. The results of TPD experiments
are simulated and quantitatively evaluated by means of an extended
transport model. From the number of desorption peaks, we obtain the
number of different adsorption and desorption mechanisms. A detailed
simulation of the peaks yields the reaction order, the frequency factor,
and the activation energy of the desorption steps. The kinetic reaction
parameters allow a mechanistic interpretation of the adsorption and
desorption processes. Here, we suppose the formation of a complex
between the carbon surface, mercury, and oxygen.