Oxygen-argon acoustic cavitation bubble in a water-methanol mixture: Effects of medium composition on sonochemical...

The objective of the present numerical study is to examine the sonochemical production within a single acoustic bubble that oscillates in an aqueous methanol solution under an oxygen-argon mixture. The produced molar yield during the strong collapse was analyzed in accordance with the system composition, i.e. the molar fraction of argon and the volume fraction of methanol. The simulation results based on 180 cases demonstrated the reproducibility of pyrolysis and combustion conditions within the bubble volume. Pure water sonolysis resulted in an optimal production at 90% molar of argon, with O, HO^· and HO₂^· as predominant species at low argon concentrations and O, HO^· et H^· at high concentrations. The addition of methanol changed the whole chemical schema evolving inside the bubble that gave rise to specific species such as CH₂OH,CH₃O,CH₂O,HCO,CO₂ and CO. A common optimum appeared at 40% molar of argon for solutions of 20% (v/v) and up of methanol. An absolute maximum was observed at 40% (v/v) of methanol, in spite of argon concentration. In addition, a significant selectivity of products was observed according to the composition of the medium.