Synergistic effects on degradation of parachlorophenol solution by combination of ultrasound and light irradiations

The degradation of papachlorophenol has been investigated under the irradiation of ultrasound and light (visible or ultraviolet light) respectively and simultaneously.We observed that parachlorophenol was degraded under the irradiation of ultrasound and ultraviolet light.The reaction follows the first-order kinetics.Under the simultaneous irradiation of ultrasound and ultraviolet light,the reaction amount is greater than the sum of that under respective irradiations of ultrasound and ultraviolet light,indicating a synergistic effect of ultrasound and ultraviolet light irradiations. On the other hand,synergistic effect was not observed when papachloraphenol was irradiated under the simultaneous irradiation of ultrasound and visible light.The synergistic effect of ultrasound and ultraviolet light is ascribed to the ultraviolet light's decomposition of hydrogen peroxide generated by ultrasound irradiation.