Fluorescence enhancement of the aqueous solution of terephthalate ion after bi-frequency sonication.

The fluorescence enhancement of the aqueous solution of terephthalate ion (TA) under orthogonal sonication of 28 kHz and 1.7 MHz ultrasonic wave has been studied. It has been found that the fluorescence intensity of TA solution after bi-frequency ultrasonic irradiation is obviously higher than the sum of those under two individual ultrasonic irradiations.