Catalytic sterilization of Escherichia coli K 12 on Ag/Al2O3 surface

Abstract

Bactericidal action of Al 2 O 3 , Ag/Al 2 O 3 and AgCl/Al 2 O 3 on pure culture of Escherichia coli K 12 was studied. Ag/Al 2 O 3 and AgCl/ Al 2 O 3 demonstrated a stronger bactericidal activity than Al 2 O 3 . The colony-forming ability of E. coli was completely lost in 0.5 min on both of Ag/Al 2 O 3 and AgCl/Al 2 O 3 at room temperature in air. The configuration of the bacteria on the catalyst surface was observed using scanning electron microscopy (SEM). Reactive oxygen species (ROS) play an important role in the expression of the bactericidal activity on the surface of catalysts by assay with O 2 /N 2 bubbling and scavenger for ROS. Furthermore, the formation of CO 2 as an oxidation product could be detected by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and be deduced by total carbon analysis. These results strongly support that the bactericidal process on the surface of Ag/Al 2 O 3 and AgCl/Al 2 O 3 was caused by the catalytic oxidation.

Efficient disinfection of Escherichia coli in water by silver loaded alumina

“…The microbes are completely inactivated in 5 min on Ag/ Al 2 O 3 surface at room temperature in air. We have proposed a catalytic oxidation mechanism that ROS as bactericide in the bactericidal process are formed on the catalyst surface by activating adsorbed oxygen in air [9,13]. In this paper, we focus our attention on the bactericidal activity of Ag/Al 2 O 3 in water to further identify the inactivation mechanism as a successive work to the former study [13], since the situation is very different from that in air.…”

“…We have proposed a catalytic oxidation mechanism that ROS as bactericide in the bactericidal process are formed on the catalyst surface by activating adsorbed oxygen in air [9,13]. In this paper, we focus our attention on the bactericidal activity of Ag/Al 2 O 3 in water to further identify the inactivation mechanism as a successive work to the former study [13], since the situation is very different from that in air. AgCl/Al 2 O 3 was also used in this study because of its low amount of eluted Ag + , and thus is applicable to water resources without having adverse health effects.…”

Morphology-dependent bactericidal activities of Ag/CeO2 catalysts against Escherichia coli

“…Therefore, the development of non-photocatalysis procedures containing abundant ROS formation is necessary for disinfection. According to the literature, many inorganic bactericidal materials such as MgO, CaO, and silver loaded materials can inactivate microorganisms through catalytic oxidation processes involving ROS [4,6,[11][12][13][14][15][16]. For pure oxides such as MgO and CaO, the bactericidal activity is low [12].…”

“…Ceria is an interesting oxide because oxygen vacancy defects can be rapidly formed, thus O vacancies and ROS in CeO 2 are naturally anticipated in catalytic processes. Since ROS play an important role in the catalytic bactericidal process [14][15][16], CeO 2 is a potential bactericidal material through ROS formation either as a catalyst or catalyst support, and thus it is important to investigate its bactericidal activity. The toxicity effects of CeO 2 nanoparticles on bacteria have been studied recently [21,22].…”

Antimicrobial activity of silver loaded MnO2 nanomaterials with different crystal phases against Escherichia coli

“…Therefore, development of a non-photocatalytic procedure providing abundant formation of ROS is necessary for achieving effective antimicrobial activity. According to the literature, many inorganic bactericidal materials such as MgO, CaO, and silver-loaded materials could efficiently inactivate microorganisms through catalytic oxidation processes involving ROS species (Sawai et al, 1997;Inoue et al, 2002;Pape et al, 2004;He et al, 2004;Chen et al, 2007;Chang et al, 2007). Among inorganic bactericidal materials, Ag nanoparticles show high bacterial activity.…”