Removal of chlorobenzene using a sequential adsorption-plasma catalytic system over Ag-, Ce- and Mn-modified activated carbon catalysts

BACKGROUND A dielectric barrier discharge reactor coupled with a series of activated carbon (AC) catalysts was applied to remove low concentrations of chlorobenzene. The catalysts were prepared via an impregnation method and their adsorption capacity and plasma-catalytic ability examined in a sequential adsorption-plasma oxidation process. RESULTS Ag/AC had the longest breakthrough time and highest breakthrough capacity among the catalysts studied. At the discharge stage, the Ag/AC catalyst had the highest CO2 yield, chlorobenzene mineralization rate and carbon balance, and the lowest emission of chlorobenzene when compared with the other catalysts under the same conditions. However, the Ag/AC catalyst exhibited the worst reducing ozone generation performance, while the Mn/AC catalyst showed the best ozone decomposition ability. The organic intermediates produced using Ag/AC and Ce/AC were simpler and in lower concentrations than those formed using Mn/AC. The adsorption capacity and catalytic activity of the Ag/AC catalyst showed no obvious decrease after five cycles. Fourier transform infrared and scanning electron microscopy-energy dispersive spectroscopy analyses after the reaction showed that some nitrogen organic intermediates and chlorine substances produced via the degradation of chlorobenzene were adsorbed onto the catalyst surface. CONCLUSIONS Ag/AC exhibited a longer breakthrough time, higher breakthrough capacity, higher CO2 yield, less chlorobenzene emission and better carbon balance when compared with the other catalysts. (c) 2019 Society of Chemical Industry