260
2018 report.. This means that if no action is taken the estimated annual deaths attributable to bacterial resistance will be 10 million by 2050.
Adsorption by using porous materials (like activated carbon, polymeric resins,
natural clay and organoclay complex adsorbents) was found to be one of the most
simple, efficient, cost-effective, flexible methods to remove fluoroquinolonesin the
wastewater treatment process. However, this technique does not lead to the complete removal of parent chemicals and their degradation products and, consequently,
other treatments are needed for their mineralization.
Advanced Oxidation Processes (AOPs) can be a good choice because, basically,
involve the generation of highly reactive free radicals, which convert the organic
contaminants into final non-toxic by-products.
Among the various semiconductors employed, TiO 2 is the most preferable material for the photo-catalytic process (high photosensitivity, non-toxic nature, large
band gap, chemical stability and low cost).
In this research the photocatalytic activity of this semiconductor immobilized
onto the surface of glass borosilicate tubes was evaluated on levofloxacin (trade
name Levaquin and other), which is an antibiotic used to treat a number of bacterial
infections including acute bacterial sinusitis, pneumonia, urinary tract infections,
chronic prostatitis, and some types of gastroenteritis. Kinetics of photoreactions
were determined in ultrapure and ground water samples spiked with levofloxacin
and photoproducts where identified by liquid chromatography coupled with
micrOTOF-Q-II-Mass Spectrometer (LC-MS, Bruker Daltonik GmbH, Bremen).
27.2 Material and Methods
Levofloxacin (MW, 361,37 g mol
−1
) pure standard (purity, 98%) was purchased
from HPC (High Purity Compounds, Cunnersdorf, Germany), all solvent for HPLC
analysis grade were purchased from Sigma Aldrich (Munich, Germany).
All the solutions were daily prepared and to avoid microbial contamination, all
glass apparatus were heat sterilized by autoclaving for 60 min at 121 °C before use.
Aseptic handling materials and laboratory facilities were used throughout the study
to maintain sterility.
The groundwater was characterized according to standard methods (APHA, 2005).
The solar experiments were performed using a solar simulator device Heraeus
Suntest CPS+ (Atlas, Chicago, USA), equipped with a 1500 W xenon arc lamp
protected with a quartz filter (total passing wavelength: 280 nm < λ < 800 nm). The
irradiation chamber was maintained at 20 °C by both circulating water from a thermostatic bath and through a conditioned airflow.
The irradiation system was dynamic: the solutions of levofloxacin (dissolved in
ultrapure water or groundwater) was passed through the borosilicate tube, coated
with TiO 2 on the internal and external surfaces, closed into the photoreactor and
irradiated with the xenon arc (Fig. 27.1) [2]. At predetermined times aliquots of
L. Scrano et al.
2018 report.. This means that if no action is taken the estimated annual deaths attributable to bacterial resistance will be 10 million by 2050.
Adsorption by using porous materials (like activated carbon, polymeric resins,
natural clay and organoclay complex adsorbents) was found to be one of the most
simple, efficient, cost-effective, flexible methods to remove fluoroquinolonesin the
wastewater treatment process. However, this technique does not lead to the complete removal of parent chemicals and their degradation products and, consequently,
other treatments are needed for their mineralization.
Advanced Oxidation Processes (AOPs) can be a good choice because, basically,
involve the generation of highly reactive free radicals, which convert the organic
contaminants into final non-toxic by-products.
Among the various semiconductors employed, TiO 2 is the most preferable material for the photo-catalytic process (high photosensitivity, non-toxic nature, large
band gap, chemical stability and low cost).
In this research the photocatalytic activity of this semiconductor immobilized
onto the surface of glass borosilicate tubes was evaluated on levofloxacin (trade
name Levaquin and other), which is an antibiotic used to treat a number of bacterial
infections including acute bacterial sinusitis, pneumonia, urinary tract infections,
chronic prostatitis, and some types of gastroenteritis. Kinetics of photoreactions
were determined in ultrapure and ground water samples spiked with levofloxacin
and photoproducts where identified by liquid chromatography coupled with
micrOTOF-Q-II-Mass Spectrometer (LC-MS, Bruker Daltonik GmbH, Bremen).
27.2 Material and Methods
Levofloxacin (MW, 361,37 g mol
−1
) pure standard (purity, 98%) was purchased
from HPC (High Purity Compounds, Cunnersdorf, Germany), all solvent for HPLC
analysis grade were purchased from Sigma Aldrich (Munich, Germany).
All the solutions were daily prepared and to avoid microbial contamination, all
glass apparatus were heat sterilized by autoclaving for 60 min at 121 °C before use.
Aseptic handling materials and laboratory facilities were used throughout the study
to maintain sterility.
The groundwater was characterized according to standard methods (APHA, 2005).
The solar experiments were performed using a solar simulator device Heraeus
Suntest CPS+ (Atlas, Chicago, USA), equipped with a 1500 W xenon arc lamp
protected with a quartz filter (total passing wavelength: 280 nm < λ < 800 nm). The
irradiation chamber was maintained at 20 °C by both circulating water from a thermostatic bath and through a conditioned airflow.
The irradiation system was dynamic: the solutions of levofloxacin (dissolved in
ultrapure water or groundwater) was passed through the borosilicate tube, coated
with TiO 2 on the internal and external surfaces, closed into the photoreactor and
irradiated with the xenon arc (Fig. 27.1) [2]. At predetermined times aliquots of
L. Scrano et al.