bismuth-oxybromide and silver-bromide

The AgI/AgBr/BiOBr0.75I0.25 nanocomposites were synthesized by a solvothermal process, followed by an in-situ ion exchange reaction. The disinfection activities of the as-synthesized photocatalyst to model cell type, Gram-negative Escherichia coli (E. coli), were investigated under visible light irradiation condition (λ≥400 nm). Results showed that 80 mg/L AgI/AgBr/BiOBr0.75I0.25 could completely inactivate 3×10(7) CFU mL(-1)E. coli cells within 30 min under visible light irradiation. Moreover, the bactericidal mechanisms involved in the photocatalytic disinfection process were systematically investigated. Ag(+) ions released from the nanocomposites negligibly contributed to the bactericidal activity, while active species including h(+), e(-) and ·O2(-) played important roles in the disinfection system. Direct contact of bacterial cells and nanoparticles was found to be the prerequisite for both the generation of ·O2(-) and the disinfection processes. The disruption of cell membrane and emission of cytoplasm directly inactivated E. coli cells. In addition, AgI/AgBr/BiOBr0.75I0.25 exhibited strong antibacterial activity toward E. coli even in four consecutive reused cycles.

Topics: Anti-Bacterial Agents; Bismuth; Bromides; Cell Membrane; Disinfection; Escherichia coli; Iodides; Light; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Nanocomposites; Photoelectron Spectroscopy; Potassium; Reactive Oxygen Species; Silver Compounds; X-Ray Diffraction

A novel Ag/AgBr/BiOBr hybrid was prepared by a rational in situ ion exchange reaction between BiOBr hierarchical microspheres and AgNO(3) in ethylene glycol followed by light reduction, which displayed superior visible light driven photocatalytic activities in sterilization of pathogenic organism and degradation of organic dye compared to N-doped P25.

Topics: Bismuth; Bromides; Ion Exchange; Silver; Silver Compounds; Silver Nitrate; Temperature; Water Pollutants, Chemical