Degradation of Toluene With Negative DC Corona Plasma Enhanced by Microdischarge

DC corona discharge has been widely used for the application of volatile organic compounds (VOCs) degradation. In this article, the microdischarge was found in an improved wire-plate corona discharge reactor, which could extremely promote the toluene degradation efficiency. Due to the porous insulating materials attached to the grounded electrode, microdischarge could be easily induced by the accumulated charge on the insulating layer during corona discharge. An influence of parameters of microdischarge was systematically investigated, such as volume resistivity of insulating materials, layer thickness (
$d$
), the number of pores (
$n$
), and pore size (
$s$
). It is found that a better toluene degradation could be obtained when a porous insulating layer with low volume resistivity and small pore was coated on the grounded electrode of the corona discharge reactor. With the polytetrafluoroethylene (PTFE) insulating layer of
$d =5 0\,\,\mu \text{m}$
, n
$= 50\,\,\mu \text{m}$
, and s
$= 10\,\,\mu \text{m}$
, the degradation efficiency of toluene reached 54.2% when the discharge power was 24 W, while the efficiency is only 40.8% compared to the negative dc corona discharge alone. Besides, the concentration of CO
₂
and CO produced during the degradation of toluene was also increased by 189 and 293 ppm due to the induction of microdischarge. The investigations on the microdischarge-enhanced corona plasma reactor could not only offer an effective way for toluene degradation but also provide new insight on the improvement of plasma reactors for VOCs’ decomposition.