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Issue 5, 2011
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Facile design and nanostructural evaluation of silver-modified titania used as disinfectant

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Abstract

Fundamental research has been carried out to define optimal “green” synthesis conditions for the production of titania (TiO2) and silver (Ag) nanocomposites (TANCs) ranging from 12.7–22.8 nm in diameter. A bottom-up colloidal approach was employed to accurately control TANC monodispersity and composition. TANCs were found to be effective at inactivating Escherichia coli (E. coli) in water. The presence of Ag in the nanocomposites induced a decrease in TiO2 band gap energy, which favoured valence to conduction band electron transfer and allowed for electron excitation using visible light. Aggregation of ultra-fine particles was prevented through the use of a long-chain polymer as evidenced by electrophoretic mobility studies. The TANCs catalyzed oxidation of bacterial membranes and cell death or disinfection. Theoretically, the TANC mode of E. coli disinfection is viawater photolysis, which results in production of hydroxyl radicals and hydrogen peroxide. These interact with the outer membrane polysaccharides and lipids, leading to lipid peroxidation, membrane weakening and resulted in cell death. Our overarching goals were to optimize the variables involved in TANC “green” synthesis and to characterize its nanostructure. High resolution (HR) transmission and scanning electron microscopic (TEM and SEM) studies demonstrated that TANCs were highly crystalline and mono-dispersive. Elemental composition of Ag and Ti, as measured by X-ray energy dispersive (EDS) and X-ray photoelectron spectroscopy (XPS) confirmed sample purity. Ultraviolet-visible (UV-VIS) spectroscopy showed that the energy band-gap of Ag modified TiO2 was in the visible range.

Graphical abstract: Facile design and nanostructural evaluation of silver-modified titania used as disinfectant

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Publication details

The article was received on 03 Jul 2010, accepted on 04 Nov 2010 and first published on 15 Dec 2010


Article type: Paper
DOI: 10.1039/C0DT00784F
Citation: Dalton Trans., 2011,40, 1047-1054
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    Facile design and nanostructural evaluation of silver-modified titania used as disinfectant

    I. Medina-Ramirez, Z. Luo, S. Bashir, R. Mernaugh and J. L. Liu, Dalton Trans., 2011, 40, 1047
    DOI: 10.1039/C0DT00784F

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