The purfication of chloroform vapors using a novel non-thermal plasma reactor (2015)

One of the innovative technologies for air pollution control is non-thermal plasma. The dielectric barrier discharge reactor is one of the reactors that applied in non thermal plasma technology for air polluation control. In dielectric barrier discharge reactor, the distance between the electrodes for electric discharge is low and led to increasing space velocity of the pollutant in the discharge zone. This increase in the velocity results in a decrease in the probability of collision of the produced active species with pollutant molecules, which consequently decreases the efficiency of pollutant degradation. The aim of this study was to design a new dielectric barrier discharge reactor for increase the dischrge gap zone.
The non-thermal plasma reactor employed in this study was made of quartz as a rectangular cube shape. In this reactor, the expanded graphite was used as the discharge electrode which was poured uniformly in the bottom of the reactor and a copper plate was on the outer surface of the reactor applied to play the role of the earth electrode. Chloroform removal efficiency as a function of flow rate, concentration of pollutants and applied voltage was investigated in this reactor. In addition, it was observed that the exhaust gas from the reactor contains nitrogen oxides, chlorine, hydrochloric acid, phosgene, trichlorobenzaldehyde and trichloroacetaldehyde.
Results of the study showed that electrical discharge was created in larger discharge gap which resulted in space velocity decrease of pollutants in this region and caused to increase of chloroform degradation. Moreover, flow rate increase affected lightly on the degradation which is owing to the adsorption property of the expanded graphite as well as an increase in discharge gap region.