Simultaneous removal of toluene and styrene by non-thermal plasma-catalysis: Effect of VOCs interaction and system configuration

Toluene and styrene were two typical aromatic VOCs which were commonly used and coexistence in the exhaust gases from industrial manufacturing. Their simultaneous removal performances under non-thermal plasma (NTP) and NTP-catalysis were carried out and compared by a single stage coaxial dielectric barrier discharge (DBD) reactor. The effects of VOCs mixture, humidity, materials filling in the discharge zoon on the removal efficiency, CO_x selectivity, byproducts types and their emission levels were deeply investigated to explore the degradation mechanism and coexistence effect. Experimental results showed that the toluene removal was significantly inhibited when treated together with styrene under plasma treatment. But that of styrene was hardly affected at the same conditions. It was found that benzaldehyde as the primary organic byproducts from styrene consumed the oxidizing particles (O and ^. OH), limiting the conversion of toluene. The introduction of Cu-doped MnO₂ materials significantly improved the VOCs removal performance with nearly 100% conversion to CO_x at a discharge power less than 30 W, as well as O₃ generation from more than 1.2 mg L^-1 by NTP to 1.6 × 10^-3 mg L^-1 by NTP-catalysis. With the help of in situ FT-IR, it was believed that catalysts not only accelerated the adsorption and degradation of pollutants but also utilized ozone to involve this process. At last, a plausible explanation on binary coexistence effect under different conditions had been suggested and discussed.