MoS2 nano flowers-activated peroxydisulfate oxidation for rapid and ef fi cient 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 center dot-, center dot OH, and center dot 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.