posted on 2017-03-22, 00:00authored byLulu Wang, Yongchun Zhao, Junying Zhang
Efficient
and economical technologies are essential to the control
of mercury, the emission of which imposes serious health concerns
and environmental risks. Photocatalysis is an attractive method for
reducing mercury emissions. Considering that titania is widely applied
in the photodegradation of toxic contaminants, this study investigated
the removal of mercury over cerium-based titania nanofibers (CBTs)
at low temperature. According to the results, in the atmosphere containing
SO2, both catalyst and UV proposed adverse effect on Hg0 oxidation. The competition between SO2 and Hg0 for active sites and the formation of cerium sulfate are
responsible for the deactivation of Hg0 removal capacity.
More interestingly, without O2, NO and HCl still exerted
a superior promoting effect on mercury removal. Entirely different
from the properties under SO2, UV and catalyst both facilitated
Hg0 oxidation with the existence of HCl. Meanwhile, effects
of the copresence of NO and SO2 on Hg0 removal
were further investigated. NO was the most dominant gas component
enhancing the removal capacity. Considerable high removal efficiency
(>80%) was observed in the presence of 300 ppm of NO and 400 ppm
of
SO2. These indicate that combining photocatalysis technology
with CBTs is a promising strategy to oxidize mercury under low-rank
coal combustion flue gas in which the concentration of HCl is relatively
low.