Methylene Blue degradation using plasma: A comparative study between the microwave plasma jet over water surface and the nanosecond pulsed discharge in gas bubbles in water

In this paper investigates the Methylene Blue degradation using two common reactors: the nanosecond pulsed discharge in oxygen bubbles and the Argon Microwave plasma jet above the treated solution. The aim of this study is to compare the evolution of the reactors' performance when the electrical conductivity increases. In deionized water, the Methylene Blue degradation and the energy efficiency in the nanosecond pulsed discharge configuration were significantly higher than the Argon microwave plasma jet. However, when the solution electrical conductivity is increased, the energy efficiency of the nanosecond pulsed discharge drops significantly by ~82%, whereas the performance of the microwave plasma jet reactors decreases by ~37% only for a greater variation of the electrical conductivity of the solution. Under these conditions, the efficiency of both reactors becomes comparable, suggesting the necessity to consider various parameters to compare the reactors' efficiency.