Decolorization of Methylene Blue Aqueous Solution by Atmospheric-Pressure Plasma Jet

Decolorization of a methylene blue aqueous solution was carried out using an atmospheric-pressure plasma jet. When the plasma jet was directly irradiated onto a methylene blue aqueous solution, the blue solution was decolorized within 10 min. Owing to plasma jet irradiation, the maximum absorbance spectral peak of the methylene blue aqueous solution decreased, and its position shifted to the short-wavelength region. This result indicates that the lengths of conjugated systems in the molecular structure of methylene blue decreased, and that the methylene blue aqueous solution was decolorized as a result of the decomposition of methylene blue.