Title: Bactericidal activities and synergistic effects of Ag-TiO₂ and Ag-TiO₂-SiO₂ nanomaterials under UV-C and dark conditions

Authors: Nhung Thi-Tuyet Hoang; Nguyen Van Suc; The-Vinh Nguyen

Addresses: Faculty of Chemical & Food Technology, Ho Chi Minh City University of Technology and Education, 01 Vo Van Ngan street, Thu Duc District, Ho Chi Minh city, Vietnam ' Faculty of Chemical & Food Technology, Ho Chi Minh City University of Technology and Education, 01 Vo Van Ngan street, Thu Duc District, Ho Chi Minh city, Vietnam ' Faculty of Environment, Ho Chi Minh City University of Technology, 268 Ly Thuong Kiet street, District 10, Ho Chi Minh city, Vietnam

Abstract: The synergistic effects of silver and titanium dioxide revealed the potential utility of Ag-TiO₂-based materials as safe disinfectants in drinking water treatment. In this work, disinfection of Escherichia coli bacteria (ATCC®25922) by using impregnation-derived Ag-P25 and gel-derived Ag-TiO₂-SiO₂ nanomaterials was conducted under both UV-C exposure and dark conditions to elucidate their synergistic effects. Under UV-C irradiation, the bactericidal activity of impregnation-derived Ag-P25 was superior to the one observed with only UV-C, a combination of AgNO₃ and UV-C, or a combination of TiO₂ and UV-C. Meanwhile, the bactericidal activities of the Ag-P25 nanoparticles in dark were quite lower than those under UV-C light, but higher than that of bare TiO₂(P25) or AgNO₃in dark conditions. The results also proved that synergistic effect of the gel-derived Ag-TiO₂-SiO₂ nanomaterial made bactericidal activities stronger than those of the Ag-P25 counterpart under both UV-C light and dark conditions. This could be ascribed to the small particle size of gel-derived Ag-TiO₂-SiO₂ (ca. 9 nm) when compared with that of impregnation-derived Ag-P25 (ca. 21 nm).

Keywords: gel-derived Ag-TiO2-SiO2; silver; titanium dioxide; silicon dioxide; silica; photocatalyst; E. coli inactivation; UV-C irradiation; ultraviolet C; dark conditions; nanomaterials; nanotechnology; safe disinfectants; drinking water treatment; Escherichia coli bacteria; disinfectant safety; nanoparticles; bactericidal activities; particle size.

DOI: 10.1504/IJNT.2015.067894

International Journal of Nanotechnology, 2015 Vol.12 No.5/6/7, pp.367 - 379

Published online: 08 Mar 2015 *

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