Influence of temperature and pressure on solute decomposition efficiency by microwave-excited plasma

Decomposition efficiency of organic solute by microwave underwater discharge was investigated using methylene blue (MB) as a test solute. It was found that the energy efficiency for the MB decomposition was strongly influenced by the discharge conditions, i.e., the solution temperature and the pressure. The most efficient MB decomposition was observed when the pressure was close to the saturated water vapor pressure. The result was explained by taking account for the power dissipation for the gas phase production in the liquid.