Successive treatment of benzene and derived byproducts by a novel plasma catalysis-adsorption process

Abstract Gas discharge plasma (catalysis) process (GDPP/GDPCP) is efficient for degrading VOCs at ambient temperature and atmospheric pressure, but the process also leads to the emission of gaseous byproducts including organic aerosols, NOx and O3. In this paper, a novel double-chamber dielectric barrier discharge (DBD) catalysis reactor, which was consisted of a gas phase packed-bed discharge chamber and a gas-liquid phase discharge chamber in series, was designed to enhance the benzene degradation and inhibit the emission of gaseous byproducts. Mn-Cu/Al2O3 catalyst was employed as the packed material in gas phase discharge chamber due to their good catalytic performance in VOCs degradation. Persulfate was added in the water of gas-liquid phase discharge chamber to reduce the emission of gaseous byproducts. The results show that Mn-Cu/Al2O3 (1:1) catalysts improved benzene degradation and CO2 selectivity compared to discharge plasma treatment alone, and the emission of O3 and NO2 was effectively reduced; moreover, an addition of persulfate in water also enhanced the degradation of benzene due to the formation of stronger active radicals via an activation of persulfate by discharge plasma. The characterization of Cu-Mn catalyst by XRD, SEM and XPS shows that Cu1.4Mn1.6O4 is one of important components of Cu-Mn composite catalyst, and the derived redox couples of Mn4+ /Mn3+ and Cu2+/Cu+ with more vacancies are helpful for adsorbing oxygen or ozone and then enhancing the degradation of benzene.