3.2. Photocatalytic properties
3.2.1. Effects of input power on the removal of TC
Fig. 6 illustrated the effect of input power on the degradation
rate of TC in plasma-TiO2 system. As shown in Fig. 6, anatase
TiO2 played a major role in the removal of aqueous TC. When the
input power of corona discharge was 36.0 W, the decomposition
rate of TC was calculated to 77.9% after 24 min in plasma-TiO2 system,
while only 61.9% in the single discharge process. Meanwhile,
the TC adsorption rate of TiO2 just reached 4.6%. With the discharge
power increased, TC removal was enhanced progressively
and the removal rate could reach 94.0% at 60.0 W. The information
showed that the removal rate of TC could be improved with the
increasing input power and the catalyst concentration, and there
existed synergistic effects between the two reaction mechanisms.
It was well known that the valence band electron and hole pairs
(h+ and e) in the catalyst surface would be stimulated by UV light
and visible light energy, leading to the generation of amounts of
active species, which made response to TC decomposition. Meanwhile,
when the applied power increased, the active materials
(high energy electron, strong electric field and chemical active species
etc.) would become stronger, militating for the removal effects
of TC effectively.