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Disinfection and Mechanistic Insights of Escherichia coli in Water by Bismuth Oxyhalide Photocatalysis
Author(s) -
Sherman Ilana,
Gerchman Yoram,
Sasson Yoel,
Gnayem Hani,
Mamane Hadas
Publication year - 2016
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12635
Subject(s) - photocatalysis , chemistry , photodissociation , radical , escherichia coli , singlet oxygen , photochemistry , irradiation , lipid peroxidation , hydroxyl radical , histidine , phototoxicity , nuclear chemistry , biophysics , oxygen , biochemistry , catalysis , biology , enzyme , organic chemistry , physics , nuclear physics , in vitro , gene
Abstract This study demonstrates the potential of a new Bi OC l 0.875 Br 0.125 photocatalyst to disinfect Escherichia coli in water under simulated solar irradiation. Photocatalytic efficiency was examined for different photocatalyst loadings, solar wavelengths, exposure times, photocatalyst concentration × contact time (Ct) concept and with the use of scavengers. To elucidate the inactivation mechanism, we examined DNA damage, membrane damage, lipid peroxidation and protein release. Both photolysis and photocatalysis were negligible under visible irradiation, but enhanced photocatalytic activity was observed under solar UVA ( λ > 320 nm) and UVB ( λ > 280 nm), with 1.5 and 3.6 log inactivation, respectively, after 40 min of irradiation. The log inactivation vs Ct curve for E. coli by UVA /Bi OC l 0.875 Br 0.125 was fairly linear, with Ct = 10 g L −1 × min, resulting in 2 log inactivation. Photocatalytic treatment led to membrane damage, but without lipid peroxidation. Accordingly, protein was released from the cells after UVA or UVA /Bi OC l 0.875 Br 0.125 treatment. Photocatalysis also increased endonuclease‐sensitive sites vs photolysis alone, by an unknown mechanism. Finally, E. coli inactivation was not influenced by the addition of tert‐butanol or l ‐histidine, implying that neither hydroxyl radicals nor singlet oxygen reactive species are involved in the inactivation process.