Inactivation of bacteria in batch suspension by fluidized ceramic tourmaline nanoparticles under oscillating radio frequency electric fields

Here, we investigated the synergistic effect of fluidized ceramic tourmaline nanoparticles (NPs) with oscillating electric fields to the inactivation of Escherichia coli in batch suspension. Different amounts of tourmaline NPs (5-100 mg) were dispersed in bacterial suspension (50 ml) and oscillating radio frequency (RF) electric field was applied at 3 V (equivalent of 1.5 V/cm electric field strength) and at varying frequencies (100 kHz and 1 MHz). The results showed high inactivation efficiency when combining fluidized tourmaline NPs and oscillating electric fields as compared to individual treatments of electric fields or tourmaline NPs only. The results showed 2.5-5-log reduction of viable E. coli concentration depending on the tourmaline concentration, electric field frequency and solution temperature. The present method shows a lot of promise as a novel and low-cost bacterial inactivation technique for water treatment applications. © 2012 Elsevier Ltd and Techna Group S.r.l