Role of humic substances in the degradation pathways and residual antibacterial activity during the photodecomposition of the antibiotic ciprofloxacin in water

Porras, Jazmín; Bedoya, Cristina; Silva-Agredo, Javier; Santamarı́a, Alexander; Fernández, Jhon J.; Torres-Palma, Ricardo A.

doi:10.1016/j.watres.2016.02.024

Cited by 130 publications

(33 citation statements)

References 33 publications

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“…Direct photolysis of organic pollutants due to electronic excitation of the molecules results in electron transfer from the excited state to the ground state of molecular oxygen [46,47], as well as homolysis to form organic radicals that also react with oxygen [48]. The presence of dissolved organic matter (DOM) can lead to the indirect degradation of organic pollutants by absorption of radiation and the consequent promotion of a photosensitive molecule to its first singlet state ( 1 DOM*), where excited humic substances accelerate the degradation rate of ciprofloxacin and decrease its antimicrobial activity as reported previously [49]. The singlet excited state generally has a short lifetime, so consequently there is no significant interaction with pollutant molecules.…”

Section: Parametersmentioning

confidence: 88%

Simultaneous degradation of ciprofloxacin, amoxicillin, sulfathiazole and sulfamethazine, and disinfection of hospital effluent after biological treatment via photo-Fenton process under ultraviolet germicidal irradiation

Perini

Tonetti

Vidal

et al. 2018

Applied Catalysis B: Environmental

127

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A UVC-assisted photo-Fenton process was applied to hospital wastewater that had been submitted to anaerobic treatment. Low iron (10 μM; 0.56 mg L −1) and H 2 O 2 (500 μM; 17 mg L −1) concentrations were used at the natural pH of the effluent (pH ≈ 7.4). Citric acid was employed as a complexation agent, at a 1:1 ratio, in order to maintain Fe 3+ soluble at this pH, avoiding extra procedures and costs associated with acidification/basification of the final effluent. The anaerobic process quantitatively reduced the biochemical oxygen demand (BOD 5), chemical oxygen demand (COD) and total organic carbon (TOC), with low removal of antibiotics present in the wastewater. Degradation of the antibiotics ciprofloxacin, amoxicillin, sulfathiazole, and sulfamethazine was studied by spiking the anaerobic effluent at initial concentrations of 200 μg L −1. The antibiotics were efficiently degraded (80-95%) using UVC radiation alone, although under this condition, no DOC removal was observed after 90 min. Further additions of H 2 O 2 and iron citrate increased the degradation rate constant (k obs), and 8% of DOC was removed. A lower pH resulted in higher k obs , although this was not essential for application of the photo-Fenton process. Irradiation with a germicidal lamp resulted in greater degradation of the antibiotics, compared to use of a black light lamp or sunlight, since the overall degradation was influenced by photolysis of the antibiotics, photolysis of H 2 O 2 , and the Fenton reaction. The photo-Fenton treatment could also be applied directly to the raw hospital wastewater, since no significant difference in degradation of the antibiotics was observed, compared to the anaerobic effluent. The photo-Fenton process under UVA and solar radiation reduced total coliforms and E. coli after 90 min. However, quantitative disinfection of these bacteria present in the Hospital effluent was only accomplished under UVC radiation.

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Section: Parametersmentioning

confidence: 88%

Simultaneous degradation of ciprofloxacin, amoxicillin, sulfathiazole and sulfamethazine, and disinfection of hospital effluent after biological treatment via photo-Fenton process under ultraviolet germicidal irradiation

Perini

Tonetti

Vidal

et al. 2018

Applied Catalysis B: Environmental

127

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“…S3). Previous studies have also shown that k for other FQs, including ciprofloxacin and sarafloxacin, varied with pH (Ge et al, 2010;Porras et al, 2016;Wei et al, 2013). To clarify the pH effect, kAP,i of the individual dissociation species was determined.…”

Section: Antibacterial Activity Bioassaymentioning

confidence: 99%

“…The environmental photochemical transformation of individual FQs is now reported in the literature (Ge et al, 2010;Ge et al, 2015;Porras et al, 2016;Sturini et al, 2010;Wei et al, 2013). For example, FQs, such as ciprofloxacin (Ge et al, 2010), danofloxacin (Sturini et al, 2012), norfloxacin (Niu et al, 2016), marbofloxacin and enrofloxacin (Sturini et al, 2010), have been found to follow apparent first-order photodegradation kinetics.…”

Section: Introductionmentioning

confidence: 98%

Exploring the aquatic photodegradation of two ionisable fluoroquinolone antibiotics – Gatifloxacin and balofloxacin: Degradation kinetics, photobyproducts and risk to the aquatic environment

Halsall

Chen

et al. 2018

Science of The Total Environment

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Fluoroquinolone antibiotics (FQs) are ubiquitous and ionisable in surface waters. Here we investigate gatifloxacin (GAT) and balofloxacin (BAL), two widely used FQs, and determine the photochemical reactivity of their respective dissociation species that arise at different pH to understand the relevance and pathways of phototransformation reactions. Simulated-sunlight experiments and matrix calculations showed that neutral forms (HFQs) of the two antibiotics had the highest apparent photolytic efficiency and hydroxyl-radical oxidation reactivity. Based on the pH-dependent photochemical reactivities, the solar apparent photodegradation half-lives (t) in sunlit surface waters ranged from 14.5-169min and was 1-2 orders of magnitude faster than hydroxyl-radical induced oxidation (t=20.9-29.8h). The corresponding pathways were proposed based on the identification of key intermediates using HPLC-ESI-MS/MS. The apparent photodegradation induced defluorination, decarboxylation, and piperazinyl oxidation and rearrangement, whereas hydroxyl-radical oxidation caused hydroxylated defluorination and piperazinyl hydroxylation. The photomodified toxicity of GAT and BAL was examined using an Escherichia coli activity assay. E. coli activity was not affected by BAL, but was significantly affected by the photo-modified solutions of GAT, indicating that primary photo-degradates have a comparable or higher antibacterial activity than the parent GAT. In fresh water and seawater this antibacterial activity remained high for up to 24h, even after GAT had undergone significant photodegradation (>1 half-life), indicating the potential impact of this chemical on microbial communities in aquatic systems.

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“…Therefore, it has been urgent that effective measures should be taken to remove tetracyclines from contaminative water. Recently, a variety of methods have been explored to decontaminate antibiotic such as adsorption [4], photocatalytic degradation [5], catalytic degradation [6], advanced oxidation [7,8], and biodegradation [9]. Among these various methods, adsorption is a superior and widely used method owing to its accessibility, being environmentally benign, and high efficiency [10].…”

Section: Introductionmentioning

confidence: 99%

One-Step Preparation of Graphene Oxide/Cellulose Nanofibril Hybrid Aerogel for Adsorptive Removal of Four Kinds of Antibiotics

Wang

Yao

Sheng

et al. 2017

Journal of Nanomaterials

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Via a one-step ultrasonication method, cellulose nanofibril/graphene oxide hybrid (GO-CNF) aerogel was successfully prepared. The as-prepared GO-CNF possessed interconnected 3D network microstructure based on GO nanosheets grown along CNF through hydrogen bonds. The aerogel exhibited superior adsorption capacity toward four kinds of antibiotics. The removal percentages (R%) of these antibiotics were 81.5%, 79.5%, 79.1%, and 73.9% for Doxycycline (DXC), Chlortetracycline (CTC), Oxytetracycline (OTC), and tetracycline (TC), respectively. Simultaneously, the adsorption isotherms were well fitted to Langmuir model and kinetics study implied that the adsorption process was attributed to pseudo-second-order model. The maximum theoretical adsorption capacities of GO-CNF were 469.7, 396.5, 386.5, and 343.8 mg·g−1 for DXC, CTC, OTC, and TC, respectively, calculated by the Langmuir isotherm models. After five cycles, importantly, the regenerated aerogels still could be used with little degradation of adsorption property. Consequently, the as-synthesized GO-CNF was a successful application of effective removal of antibiotics.

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Role of humic substances in the degradation pathways and residual antibacterial activity during the photodecomposition of the antibiotic ciprofloxacin in water

Cited by 130 publications

References 33 publications

Simultaneous degradation of ciprofloxacin, amoxicillin, sulfathiazole and sulfamethazine, and disinfection of hospital effluent after biological treatment via photo-Fenton process under ultraviolet germicidal irradiation

Simultaneous degradation of ciprofloxacin, amoxicillin, sulfathiazole and sulfamethazine, and disinfection of hospital effluent after biological treatment via photo-Fenton process under ultraviolet germicidal irradiation

Exploring the aquatic photodegradation of two ionisable fluoroquinolone antibiotics – Gatifloxacin and balofloxacin: Degradation kinetics, photobyproducts and risk to the aquatic environment

One-Step Preparation of Graphene Oxide/Cellulose Nanofibril Hybrid Aerogel for Adsorptive Removal of Four Kinds of Antibiotics

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