Synergetic physical damage and chemical oxidation for highly efficient and residue-free water disinfection

Abstract

Waterborne pathogens, in particular, emerging antibiotic-resistant bacteria (ARB), can cause serious infectious diseases, posing a huge threat to public health. However, existing water disinfection technologies are often not only energy and chemical intensive but also inefficient at eliminating antibiotic resistance genes (ARGs). Here we show a sequential electrochemical process of ‘chemical (H2O2 pre-treatment)–physical (nanotip electroporation)–chemical (•OH injection)’ that is highly effective in inactivating ARB and removing ARGs. The bacteria are first pre-treated by H2O2 generated via two-electron water oxidation in the SnO2−x/TiO2 anode region to reduce the defences of bacterial outer walls against electroporation. Then, the ‘softened’ and ‘weakened’ bacteria are easily punctured by electroporation in the Pd-Au/TiO2 cathode region and by synchronously injected abundant •OH generated via three-electron oxygen reduction. Bacterial inclusions, including nuclear body and cytoplasm, are effectively decomposed by •OH oxidation, resulting in the destruction of the entire cell structure from the inside out. This bactericidal mechanism of synergetic physical damage and chemical oxidation inactivated >99.9999% of ARB and removed ~99% of ARGs at short retention time (~16 s), high flux (~4.5 m3 h−1 m−2) and low energy consumption (~42.4 Wh m−3) over 15 days of continuous operation. This approach may act as an alternative to meet the urgent need for efficient and residue-free water disinfection. Zhang et al. present a sequential electrochemical process that enables synergetic physical damage and chemical oxidation of antibiotic-resistant bacteria and antibiotic resistance genes, providing an efficient and residue-free water disinfection approach.