Efficient bacteria inactivation by ligand-induced continuous generation of hydroxyl radicals in Fenton-like reaction

Highlights: • Tris-Co(II) complex-H₂O₂ could generate hydroxyl radicals continuously. • Tris-Co(II) complexes are apt to combine with E. Coli by electrostatic interactions. • High-efficiency inactivation of E. Coli was realized in the proposed system. -- Abstract: Fenton/Fenton-like reaction is often used as an efficient method to generate hydroxyl radicals (HO) for bacteria inactivation in aqueous solution. However, inactivation efficiency of bacteria in aqueous solution using Fenton/Fenton-like reactions needs to further improve as a result of transient generation of HO. In this paper, we found that the formation of Tris-Co(II) complexes could decrease the redox potential of Co(III)/Co(II), facilitating the transformation of Tris-Co(III) complexes into Tris-Co(II) complexes. Therefore, HO could be generated continuously in the presence of H₂O₂. Especially, Tris-Co(II) complexes are apt to combine with Escherichia Coli cells by electrostatic interactions, inducing a higher utilization ratio of the generated HO. Therefore, the proposed Tris-Co(II) complex-H₂O₂ system could be employed as a high-efficiency sterilizing reagent for inactivation of E. Coli. This work provides a promising strategy for bacterial inactivation via an economic and eco-friendly manner.