Water scarcity and water contamination due to the extensive use of organic compounds in industries trigger us to adopt modern techniques for wastewater treatment. In this research, we developed a new dielectric barrier discharge (DBD) system which was evaluated for the degradation of nitrobenzene in water under different experimental arrangements. DBD produces an enormous amount of active species like O3, •O, O2+ and O2− and •OH to degrade the pollutants. In this study, NB (Nitrobenzene) was treated from wastewater by changing the gas flow rate, adopting different carrier gas, by adding inhibitors and promoters and the effect of applied voltage on the production of active species to check the effectiveness of the DBD system. The DBD system was evaluated based on input power, degradation efficiency and energy yield compared with other advanced oxidation processes. The energy yield of the DBD system was 1.253 mg/kWh for the degradation of 20 mg/L of NB to 75% in 60 min with the discharge power of 0.538 W, which displays better results in comparison with the other AOPs regarding energy yield and the degradation efficiency of the pollutant. The results illustrate the significance of the system and further suggest its application to industrial-scale treatment.
The bactericidal effect on the representative type of Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis in drinking water was investigated in this paper by using dielectric barrier discharge (DBD) advanced oxidation technology. The sterilizing rates under different conditions of reaction time t, input voltage V, pH value, and initial concentration of bacteria C0 were investigated to figure out the optimum sterilization conditions. Our observations and comparisons of cell morphology alteration by scanning electron microscopy and transmission electron microscopy revealed the sterilization mechanisms. The results showed that the sterilizing rate increased obviously with the extension of reaction time t and the rise of input voltage V. The optimal sterilization effect was achieved when the pH value was 7.1. As the initial concentration of bacteria rose, the sterilizing rate decreased. When the input voltage was 2.2 kV and the initial concentration of bacteria was relatively low, the sterilizing rate almost reached 100% after a certain treatment time in neutral aqueous solution. The reasons for the great damage of cell structure and the killing of bacteria are the oxidation of O3, OH and the accumulation of active species produced by DBD. The article provides a certain theoretical and experimental basis for DBD application in water pollution treatment.