Title of article :
Bactericidal action of illuminated TiO2 on pure Escherichia coli and natural bacterial consortia: post-irradiation events in the dark and assessment of the effective disinfection time
Author/Authors :
Rincَn، نويسنده , , Angela-Guiovana and Pulgarin، نويسنده , , Cesar، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2004
Pages :
14
From page :
99
To page :
112
Abstract :
Bactericidal action of illuminated TiO2 on pure culture of Escherichia coli K12 and bacterial consortium was studied. Photocatalytic E. coli inactivation rate was dependent on the biological parameters such as: physiological state, generation and initial concentration of bacteria. The behavior of the bacterial suspension during the subsequent dark period was discussed in order to estimate the potential of using the photocatalytic treatment process in a real water disinfection situation. fective disinfection time (EDT) was defined as the time required for total inactivation of bacteria without re-growth in a subsequent dark period referenced at 48 h. rease of E. coli concentration was observed after illumination of bacteria without TiO2 (named here as photolysis). In the presence of TiO2 (photocatalysis), the decrease of bacteria continues in the dark, and no regrowth was observed within the following 60 h. The extent of this “residual disinfecting effect” was dependent on the light intensity (400 or 1000 W/m2) applied during the illumination period. Thus, EDT was reached in photocatalytic but not in photolytic treatment. ial consortia present in two different wastewaters were phototreated with and without TiO2 and a significant difference in bacterial sensitivity to both phototreatments was observed. Enterococcus sp. appear to be less sensitive than coliforms and other Gram-negative bacteria. Considerable differences in photoreactivity were observed for both samples taken at the same place but at different date. rst sample named as wastewater 1, exhibited a bacteriostatic but no bactericidal effect after both phototreatments; the addition of TiO2 accelerated the solar disinfection. In the second sample, wastewater 2, a bactericidal effect was observed in photolytic and photocatalytic experiments and the EDT was attained in both cases, even if the bacterial inactivation rate was the lowest in the presence of the catalyst. The chemical oxygen demand (COD) decreases during photocatalytic treatment, but not during the photolytic one; whereas the Dissolved organic carbon (DOC) increases in both cases. COD/DOC ratio decreases during phototreatments.
Keywords :
TIO2 , photocatalysis , E. coli , Bactericidal effect , Bacteriostatic effect , Bacterial recovery , Enterococcus sp. , Regrowth , Bacteria consortium , Solar water disinfection
Journal title :
Applied Catalysis B: Environmental
Serial Year :
2004
Journal title :
Applied Catalysis B: Environmental
Record number :
1446761
Link To Document :
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