The degradation of wastewater by plasma activated water (PAW) mainly relies on the interaction between reactive species, such as •OH, H2O2 and O3 generated by discharges, and contaminant particles. A coaxial dielectric barrier discharge (DBD) device with bubbling system, was built to achieve the generation of PAW by using high frequency AC power supply. Through the electrical and optical diagnosis of DBD, typical voltage and current wave-forms were obtained, and the composition of discharge products was analyzed. Combined with the detection of the conductivity and pH value of activated water, the influence of different experimental parameters (gas species, flow rate, bubble size and discharge voltage) on the effect of PAW was verified. Results showed that argon discharge is more uniform while air discharge produces more active particle species, which increases the chemical activity of PAW. The bubble size and the gas flow rate have optimal combination for the improvement of the activation of PAW. The higher the discharge voltage is, the stronger the activity of PAW is. However, air discharges with too high voltage will result in generation of intensive heat in the dis-charge device, leading to additional energy consumption. These results provide the basis for the optimization of discharge parameters, which is very important for improving the efficiency of wastewater treatment and for promoting the industrial development of plasma technology.
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