Enhanced visible-light photodegradation of fluoroquinolone-based antibiotics and growth inhibition using Ag-TiO nanoparticles
Antibiotics in wastewater represent a growing and worrying menace for environmental and human health fostering the spread of antimicrobial resistance. Titanium dioxide (TiO 2 ) is a well-studied and well-performing photocatalyst for wastewater treatment. However, it presents drawbacks linked with th...
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Published in | RSC advances Vol. 11; no. 23; pp. 1398 - 13991 |
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Main Authors | , , , , , , |
Format | Journal Article |
Published |
13.04.2021
|
Online Access | Get full text |
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Summary: | Antibiotics in wastewater represent a growing and worrying menace for environmental and human health fostering the spread of antimicrobial resistance. Titanium dioxide (TiO
2
) is a well-studied and well-performing photocatalyst for wastewater treatment. However, it presents drawbacks linked with the high energy needed for its activation and the fast electron-hole pair recombination. In this work, TiO
2
nanoparticles were decorated with Ag nanoparticles by a facile photochemical reduction method to obtain an increased photocatalytic response under visible light. Although similar materials have been reported, we advanced this field by performing a study of the photocatalytic mechanism for Ag-TiO
2
nanoparticles (Ag-TiO
2
NPs) under visible light taking in consideration also the rutile phase of the TiO
2
nanoparticles. Moreover, we examined the Ag-TiO
2
NPs photocatalytic performance against two antibiotics from the same family. The obtained Ag-TiO
2
NPs were fully characterised. The results showed that Ag NPs (average size: 23.9 ± 18.3 nm) were homogeneously dispersed on the TiO
2
surface and the photo-response of the Ag-TiO
2
NPs was greatly enhanced in the visible light region when compared to TiO
2
P25. Hence, the obtained Ag-TiO
2
NPs showed excellent photocatalytic degradation efficiency towards the two fluoroquinolone-based antibiotics ciprofloxacin (92%) and norfloxacin (94%) after 240 min of visible light irradiation, demonstrating a possible application of these particles in wastewater treatment. In addition, it was also proved that, after five Ag-TiO
2
NPs re-utilisations in consecutive ciprofloxacin photodegradation reactions, only a photocatalytic efficiency drop of 8% was observed. Scavengers experiments demonstrated that the photocatalytic mechanism of ciprofloxacin degradation in the presence of Ag-TiO
2
NPs is mainly driven by holes and &z.rad;OH radicals, and that the rutile phase in the system plays a crucial role. Finally, Ag-TiO
2
NPs showed also antibacterial activity towards
Escherichia coli
(
E. coli
) opening the avenue for a possible use of this material in hospital wastewater treatment.
Ag nanoparticles decorated-TiO
2
P25 are a viable alternative for the degradation, through a rutile-mediated mechanism, of fluoroquinolone-based antibiotics under visible light irradiation and, at the same time, for bacteria inactivation in water. |
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Bibliography: | 10.1039/d0ra10403e Electronic supplementary information (ESI) available. See DOI |
ISSN: | 2046-2069 |
DOI: | 10.1039/d0ra10403e |