MoS2 nanoflowers-activated peroxydisulfate oxidation for rapid and efficient water disinfection

MoS₂ nanoflowers were fabricated and deposited on porous graphite felt (MoS₂-GF) via the hydrothermal treatment to activate peroxydisulfate (PDS) for water disinfection. The surface textural and chemical characterization indicated that the MoS₂ nanoflowers were successfully grown on the graphite felt. MoS₂-activated PDS oxidation with 0.25 ​g/L MoS₂ and 0.2 ​mM PDS achieved above 7-log removal of E. coli within contact time of 25 ​min. Gram-negative bacteria (E. coli and P. aeruginosa) were more sensitive to the oxidation reactions than the Gram-positive ones (E. faecalis and S. aureus) due to their larger cell sizes and thinner wall thicknesses. The live/dead backlight staining experiments and scanning electron microscopy characterization revealed that the bacteria were inactivated via cell membrane damage. The free radical quenching experiments suggested that the SO₄^•-, •OH, and •O²⁻ were the main reactive radicals involved into bacteria inactivation. The MoS₂-activated PDS oxidation also achieved undetectable heterotrophic plate count for real river water lake water within contact time of 120 ​min.