Different inactivation behaviors and mechanisms of representative pathogens (Escherichia coli bacteria, human adenoviruses and Bacillus subtilis spores) in g-C3N4-based metal-free visible-light-enabled photocatalytic disinfection

Abstract

Continuous economic loss and even human death caused by various microbial pathogens in drinking water call for the development of water disinfection systems with the features of environmentally friendly nature, high inactivation efficacy without pathogen regrowth, facile disinfection operation and low energy consumption. Alternatively, g-C 3 N 4 -based visible-light-enabled photocatalytic disinfection can meet the above requirements and thus has attracted increasing interest in recent years. Here, we explored for the first time the antimicrobial ability and mechanisms of a wide spectrum of representative pathogens ranging from bacteria ( Escherichia coli ), to viruses (human adenoviruses) and spores ( Bacillus subtilis spores) by g-C 3 N 4 /Vis system with the assistance of two common oxidants (H 2 O 2 and PMS), especially in a comparative perspective. Pristine g-C 3 N 4 could achieve a complete inactivation of bacteria (5-log) within 150 min, but displayed negligible antimicrobial activity against human viruses and spores (< 0.5-log). Fortunately, simple addition of oxidants into the system could greatly enhance the inactivation of bacteria (5-log with PMS within 120 min) and human viruses (2.6-log with H 2 O 2 within 150 min). Roles of reactive oxygen species were found to be quite different in the disinfection processes, depending on both types of chemical oxidants and microbial pathogens. Additionally, disinfection efficiency could be facilely and effectively improved by statistical optimization of two important operating factors (i.e., catalyst loading and oxidant addition). Selection of added oxidants was determined by not only the target pathogen but also the water matrix. As a proof of concept, this work can provide some meaningful and useful information for advancing the field of green and sustainable water disinfection.

Metal-free photocatalysts for solar-driven water disinfection: recent progress and challenges

“…In addition, the inactivation ability of the g-C 3 N 4 /vis system against viruses, bacteria, and spores could be enhanced by the addition of hydrogen peroxide (H 2 O 2 ) and peroxymonosulfate (PMS). 33 It has been revealed that the addition of H 2 O 2 produced ˙OH, which reacted with the protein coating of the target virus and caused irreversible modification, thus improving the antiviral ability of the system, and PMS was more conducive to the inactivation of bacteria. Moreover, considering the good biocompatibility of g-C 3 N 4 , it is a potential choice to apply it to the agricultural field for the inactivation of plant pathogens.…”

A review on the potential of photocatalysis in combatting SARS-CoV-2 in wastewater

“…The technology of photocatalysis that employs carbon-based photocatalyst has attracted much attention due to the zero risk of metal leaching into the water system and optimum natural light-harvesting capability [ [77] , [78] , [79] ]. The non-metal photocatalysts that have been developed for virus disinfection include carbon-based materials such fullerene [ 80 , 81 ] carbon nanotube [ 82 ], carbon dot [ 83 , 84 ], and graphitic carbon nitride (g-C 3 N 4 ) [ 78 , 85 , 86 ].…”

Research Progress on Inactivation of Bacteriophages by Visible-Light Photocatalytic Composite Materials: A Mini Review

“…In contrast to conventional disinfection methods, photocatalytic disinfection showcases extensive bactericidal effectiveness [ 18 ], simultaneously addressing a variety of microorganisms such as bacteria, viruses, and fungi. The notable advantage lies in the lack of chemical residues after treatment, minimizing adverse impacts on both the environment and human health [ 19 ]. Moreover, the sustainability of the photocatalytic disinfection process is noteworthy, as it only requires a light source to activate the catalyst, eliminating the necessity for frequent chemical replacements or additions.…”