Bactericidal effects of titanium dioxide-based photocatalysts

Heather Coleman, C.P. Marquis, J.A. Scott, S.-S. Chin, R. Amal

Research output: Contribution to journalArticle

114 Citations (Scopus)

Abstract

The photocatalytic degradation of E. coli in water by various catalysts was investigated in a batch spiral reactor. Commercial Degussa P25 (P25), as well as novel magnetic and hydrothermally prepared photocatalysts (MPC and HPC) were investigated in a slurry system. P25 was found to be the most effective catalyst, followed by the HPC and the MPC. Cell destructions followed first order kinetics. Non-buffered samples displayed a greater bactericidal efficiency which was attributed to a decrease in electrostatic repulsions between TiO2 and E. coli and also elevated stress on E. coli at acidic pH. Buffered (NaHCO3) samples showed a decrease in bactericidal efficiency due to HCO3− ions competing with oxidising species and blocking (by adsorption) the TiO2 particles. The optimum catalyst loading for P25 and HPC was 1 and 2 g/L for MPC and was attributed to mass transfer effects (bulk diffusion, available active site and shadowing). An immobilised P25 system was found to be more efficient than the MPC and comparable with the HPC in suspension. The addition of silver to the immobilised system was found to enhance the photocatalytic degradation.
LanguageEnglish
Pages55-63
JournalChemical Engineering Journal
Volume113
Issue number1
Early online date21 Sep 2005
DOIs
Publication statusE-pub ahead of print - 21 Sep 2005

Fingerprint

Photocatalysts
Titanium dioxide
Escherichia coli
catalyst
Catalysts
Degradation
degradation
Silver
slurry
mass transfer
Electrostatics
silver
Suspensions
Mass transfer
Ions
adsorption
Adsorption
kinetics
Kinetics
ion

Keywords

  • Photocatalysis
  • E. coli
  • Titanium dioxide
  • Magnetic photocatalyst
  • Hydrothermal photocatalyst
  • Immobilised TiO2
  • Silver deposited TiO2

Cite this

Coleman, Heather ; Marquis, C.P. ; Scott, J.A. ; Chin, S.-S. ; Amal, R. / Bactericidal effects of titanium dioxide-based photocatalysts. In: Chemical Engineering Journal. 2005 ; Vol. 113, No. 1. pp. 55-63.
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Bactericidal effects of titanium dioxide-based photocatalysts. / Coleman, Heather; Marquis, C.P.; Scott, J.A.; Chin, S.-S.; Amal, R.

In: Chemical Engineering Journal, Vol. 113, No. 1, 21.09.2005, p. 55-63.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Bactericidal effects of titanium dioxide-based photocatalysts

AU - Coleman, Heather

AU - Marquis, C.P.

AU - Scott, J.A.

AU - Chin, S.-S.

AU - Amal, R.

PY - 2005/9/21

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N2 - The photocatalytic degradation of E. coli in water by various catalysts was investigated in a batch spiral reactor. Commercial Degussa P25 (P25), as well as novel magnetic and hydrothermally prepared photocatalysts (MPC and HPC) were investigated in a slurry system. P25 was found to be the most effective catalyst, followed by the HPC and the MPC. Cell destructions followed first order kinetics. Non-buffered samples displayed a greater bactericidal efficiency which was attributed to a decrease in electrostatic repulsions between TiO2 and E. coli and also elevated stress on E. coli at acidic pH. Buffered (NaHCO3) samples showed a decrease in bactericidal efficiency due to HCO3− ions competing with oxidising species and blocking (by adsorption) the TiO2 particles. The optimum catalyst loading for P25 and HPC was 1 and 2 g/L for MPC and was attributed to mass transfer effects (bulk diffusion, available active site and shadowing). An immobilised P25 system was found to be more efficient than the MPC and comparable with the HPC in suspension. The addition of silver to the immobilised system was found to enhance the photocatalytic degradation.

AB - The photocatalytic degradation of E. coli in water by various catalysts was investigated in a batch spiral reactor. Commercial Degussa P25 (P25), as well as novel magnetic and hydrothermally prepared photocatalysts (MPC and HPC) were investigated in a slurry system. P25 was found to be the most effective catalyst, followed by the HPC and the MPC. Cell destructions followed first order kinetics. Non-buffered samples displayed a greater bactericidal efficiency which was attributed to a decrease in electrostatic repulsions between TiO2 and E. coli and also elevated stress on E. coli at acidic pH. Buffered (NaHCO3) samples showed a decrease in bactericidal efficiency due to HCO3− ions competing with oxidising species and blocking (by adsorption) the TiO2 particles. The optimum catalyst loading for P25 and HPC was 1 and 2 g/L for MPC and was attributed to mass transfer effects (bulk diffusion, available active site and shadowing). An immobilised P25 system was found to be more efficient than the MPC and comparable with the HPC in suspension. The addition of silver to the immobilised system was found to enhance the photocatalytic degradation.

KW - Photocatalysis

KW - E. coli

KW - Titanium dioxide

KW - Magnetic photocatalyst

KW - Hydrothermal photocatalyst

KW - Immobilised TiO2

KW - Silver deposited TiO2

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