Photocatalytic Degradation of Pathogenic Bacteria with AgI/TiO2 under Visible Light Irradiation

Chun Hu,* Jian Guo, Jiuhui Qu, and Xuexiang Hu
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
Langmuir, 2007, 23 (9), pp 4982–4987
DOI: 10.1021/la063626x
Publication Date (Web): March 21, 2007
Copyright © 2007 American Chemical Society
*

 Corresponding author. Phone:  +86-19 6284-9628; fax:  +86-10-6292 3541; e-mail:  huchun@rcees.ac.cn.

Abstract

Abstract Image

The photocatalytic disinfection of pathogenic bacteria in water was investigated systematically with AgI/TiO2 under visible light (λ > 420 nm) irradiation. The catalyst was found to be highly effective in killing Escherichia coli and Staphylococcus aureus. The adsorbed •OH and hVB+ on the surface of the catalyst were proposed to be the main active oxygen species by study of electron spin resonance and the effect of radical scavengers. The process of destruction of the cell wall and the cell membrane was verified by TEM, potassium ion leakage, lipid peroxidation, and FT-IR measurements. Some products from photocatalytic degradation of bacteria such as aldehydes, ketones, and carboxylic acids were identified by FT-IR spectroscopy. These results suggested that the photocatalytic degradation of the cell structure caused the cell death. The electrostatic force interaction of the bacteria−catalyst significantly affected the efficiency of disinfection on the basis of the E. coli inactivation under different conditions.

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History

  • Published In Issue April 24, 2007
  • Received December 15, 2006
    Revised January 31, 2007

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