Piezo-catalytic persulfate activation system for water advanced disinfection: Process efficiency and inactivation mechanisms

This study developed a novel method based on piezoelectric catalytic persulfate (PS) activation for water advanced disinfection. Silver modified barium titanate (Ag-BTO) was synthesized and utilized as a piezoelectric catalyst to activate PS under ultrasonic vibration (US) for Escherichia coli inactivation. The newly developed US/Ag-BTO/PS process achieved a 6.2 log inactivation within 5 min and 20 min, respectively, for E. coli at culturable state and viable but nonculturable (VBNC) state. The high efficiency on E. coli inactivation was contributed by the successive generation of hydroxyl radicals and sulfate radicals via PS activation by piezo-catalytically generated electrons and superoxide radicals. Interestingly and more importantly, a synergism between ultrasonication and radical oxidation was found by using the US/Ag-BTO/PS process for E. coli inactivation. The ultrasonication disrupted cell membrane of E. coli , accelerated the permeation of the radicals and enhanced the following inner metabolic dysfunction and enzyme oxidation by radicals. The catalyst maintained a good stability and reusability, and the efficacy of the new disinfection strategy was also demonstrated in real wastewater effluent and surface water. The findings in this study suggest the merit of using the US/Ag-BTO/PS process for water advanced disinfection and provide an alternative solution in addressing the issue of microbial resurrection after conventional water disinfection treatment.