Degradation of methylene blue under multibubble sonoluminescence condition

Methylene blue (MB) is one of typical textile dyestuffs that cannot be degraded by a conventional method such as biological treatment. In this study, degradation of MB in aqueous solution under ultrasonic field at the multibubble sonoluminescence (MBSL) condition was tried for the first time. At the optimum condition of MBSL, 0.1 mM MB solution was degraded completely within 30 min, which is quite faster than the reaction rate for the photocatalytic degradation of MB in aqueous TiO2 dispersions under UV-irradiation. The sonochemical degradation of MB at the MBSL condition was found to be first-order with respect to MB concentration. Also, it has been found that MB was degraded by the oxidation process by OH radicals.