Ultrasonic enhancement of photo-catalytic oxidation of surfactant

Abstract

Photo-catalytic oxidation of surfactant (polyoxyethylene-alkyl-ether, C14H29O(CH2CH2)7H, hereinafter referred as SS-70) enhanced by high power ultrasound is examined. The influences of the ultrasonic power and the stirring speed on the degradation rate are investigated. 1000 ml of 100ppm SS-70 is decomposed totally in about 20 minutes in the photo-catalytic process combined with the ultrasonic irradiation. Without ultrasonic irradiation, the decomposition needs more than 1 hour. The optimum conditions for the hybrid degradation process are discussed. It is found that the stirring speed largely influenced the degradation efficiency. It is considered that the catalyst particles might be localized by ultrasonic standing wave, and caused inhibition to the decomposition in the degradation process. However, by high stirring speed, the inhibition could be overcome.