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Study of bacterial adhesion onto immobilized TiO2: Effect on the photocatalytic activity for disinfection applications

Paper ID Volume ID Publish Year Pages File Format Full-Text
55039 47038 2013 7 PDF Available
Title
Study of bacterial adhesion onto immobilized TiO2: Effect on the photocatalytic activity for disinfection applications
Abstract

A study has been carried out to determine the influence of bacterial adhesion onto immobilized TiO2 on the photocatalytic efficiency for bacteria inactivation. Two bacterial strains with differences in their membrane structure (Escherichia coli and Enterococcus faecalis) have been characterized in various suspensions for adhesion to the TiO2 catalyst and surface charge. Non-meaningful differences have been observed regarding the adhesion properties between both bacteria. In contrast, the configuration of the catalyst and the composition of the suspension impacted the extent of bacterial adhesion. The solution affected the adhesion between bacteria and catalyst due to its influence on electrostatic forces between them. Under electrostatically favourable conditions, hydrophobicity is the primary mechanism of adhesion. Under unfavourable conditions aquatic chemistry governs the bacterial adhesion process. Organic matter in combination with divalent ions leads to the highest level of adhesion. This may be due to the presence of Ca2+ which can bridge between bacteria and catalyst. Additionally, Ca2+ can also bridge with organic matter, which can act as source of nutrients for bacteria. Despite the solution ionic strength being low, divalent cations can contribute to the compression of the electric double layer, enhancing cell-catalyst interactions and subsequent adhesion. The bacterial adhesion observed in wastewaters might be responsible for the fact photocatalytic bacterial inactivation efficiency was not as low as expected since the main role of ions and organic matter is to act as scavengers of hydroxyl radicals.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (124 K)Download as PowerPoint slideHighlights► Bacteria–TiO2 adhesion affects the photocatalytic bacterial inactivation efficiency. ► No significant differences in adhesion of Gram positive and Gram negative bacteria. ► Hydrophobicity controls adhesion under electrostatically favourable conditions. ► Under unfavourable conditions aquatic chemistry governs bacterial adhesion process. ► Improved adhesion counteracts radical scavenging effects in wastewaters.

Keywords
Photocatalysis; Disinfection; Immobilized TiO2; E. coli; E. faecalis; Adhesion
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Study of bacterial adhesion onto immobilized TiO2: Effect on the photocatalytic activity for disinfection applications
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 209, 15 June 2013, Pages 140–146
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us