Single electrode Ar bubbled plasma source for methylene blue degradation and concurrent synthesis of carbon based nanoparticles

•A new possibility of generating in-liquids gas bubbled plasma by using a single electrode placed in a quartz tube is proposed.•The ignition mechanism of plasma is analyzed.•The plasma emission shows the presence of active species which are important for solutions treatment.•The plasma has a high yield in the degradation of methylene blue solutions.•It is shown for the first time the concurrent synthesis of solid carbon nanostructures during methylene blue degradation.

This work presents a new possibility of generating in-liquids Ar bubbled plasma by using a single electrode placed in a quartz tube. When the electrode is powered with ac high voltage the plasma is generated between the electrode's free end and the wall of Ar bubble. The ignition mechanism of plasma is analyzed and the generated active species are identified. The plasma was tested for the decomposition of methylene blue aqueous solutions and for the concurrent synthesis of very small solid particles. The influence of the methylene blue initial concentration and of the treatment time on the processes was studied.