Dual-Frequency Ultrasonic Inactivation of Escherichia coli and Enterococcus faecalis Using Persulfate: A Synergistic Effect

Dual-frequency ultrasound (DFUS) has received considerable attention for enhanced inactivation of microbial pathogens medical treatment, but remains little investigated water disinfection. This study is focused on E. coli and faecalis in aqueous solution under dual-frequency ultrasonication at 120 + 1700 kHz using persulfate. Single-frequency ultrasonic showed the higher efficiency kHz, compared to kHz. Under experimental conditions used, no measurable synergy between two frequencies was observed absence A high time-based synergistic effect terms total (5-log) both bacterial species achieved by DFUS-activated persulfate with indices 1.8–5.0. We assume that this attributed increased generation reactive oxygen (primarily, sulfate anion (SO4•−) hydroxyl (•OH) radicals) as a result acoustic cavitation. Radical probing scavenging tests confirmed radicals nearly equal contribution •OH SO4•−. method could be an attractive alternative ultraviolet technology fast effective