Fig. 2 shows the performance of the constructed wetland on
mercury removal, after 648 h (27 days) of experiment in terms of
the ratio C/Co against time plot. It can be seen a first order like
decaying behavior with speed constant parameter k of 0.001 h1
to the control experiment and 0.007 h1 for the constructed wetland
process.
Removal of heavy metals in wetlands depends on the exposure
time, the metal species and the plant species used among others
factors. The first order kinetic parameter k for the constructed wetland
was 7 times higher than the control experiment under the
same experimental conditions (except the presence of plants), what permits to conclude that T. domingensis was responsible for
the reduction of 99.6 ± 0.4% of mercury concentration in the
system.