Influence of pH on the sonolysis of ciprofloxacin: Biodegradability, ecotoxicity and antibiotic activity of its degradation products

Bel, Evelien De; Dewulf, Jo; Witte, Bruno De; Langenhove, Herman Van; Janssen, Colin R.

doi:10.1016/j.chemosphere.2009.07.033

Cited by 147 publications

(56 citation statements)

References 30 publications

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“…Thus, the BOD 5 /COD ratio reached almost 0.4, which shows that it can be easily biodegradable. The toxicity increase in the treated sample in the initial period of treatment (20 min) shows that some toxic compounds are formed during the degradation (De Bel et al 2009, and similar profile was shown by fluoxetine and carbamazepine only after a longer time of irradiation (Rao et al 2016;Serna-Galvis et al 2015). Only Environ Chem Lett a slight reduction in total organic carbon and toxicity removal was observed in the case of catalytic ozonation and ozonation of tetracycline (Wang et al 2011).…”

Section: Sonoelectrochemical Methodssupporting

confidence: 61%

Degradation of pharmaceuticals by ultrasound-based advanced oxidation process

2016

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Water pollution by pharmaceutically active compounds is an emerging issue. Toxicological studies reveal that pharmaceuticals are indeed toxic for living organisms. The lack of suitable treatment technology for the complete removal of pharmaceuticals is therefore a major challenge. Advanced oxidation processes are emerging removal techniques that have many advantages versus conventional technologies. Many studies indicate that advanced oxidation processes, either in single or in combination with other degradation techniques, can enhance the degradation of pharmaceuticals in aqueous solutions. Here, we review the degradation of pharmaceuticals by sonolysis, an oxidation processes using ultrasound. In this technique, hydroxyl radicals are generated by pyrolytic cleavage of water molecules. We review the influence of operational parameters, additives and hybrid techniques on the degradation of pharmaceuticals. The maximum degradation of organic compounds was observed in the frequency range of 100-1000 kHz, which is in the high-frequency medium-power ultrasound. Even though almost all the experiments presented more than 90 % removal and good biodegradability of the target compound, good mineralization and the toxicity removal were hardly achieved. The efficiency of the degradation varies with water matrixes and varying pH. Major pathways of degradation are hydroxylation, dehalogenation, demethylation, decarboxylation, deamination, etc. More hybrid techniques have to be developed to scale up the application of ultrasound.

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Section: Sonoelectrochemical Methodssupporting

confidence: 61%

Degradation of pharmaceuticals by ultrasound-based advanced oxidation process

2016

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“…There is a great possibility that electrochemical oxidation products also retain the biological effects of their parent compounds, and even develop new undesired bioeffects. In earlier studies (De Bel et al, 2009;Michael et al, 2010;Vasquez et al, 2013), residual antibacterial activity and toxicity changes in FQs after other oxidation processes, such as ozonation, UV treatment, and photocatalysis have been reported. Therefore, the issue cannot merely be addressed by elucidating the structures of oxidation products.…”

Section: Introductionmentioning

confidence: 96%

Electrochemical oxidation of fluoroquinolone antibiotics: Mechanism, residual antibacterial activity and toxicity change

et al. 2016

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In this paper, we studied the electrochemical oxidation mechanisms of three typical fluoroquinolone antibiotics (FQs), and investigated residual antibacterial activity and toxicity changes after oxidation processes. Electrochemistry coupled to mass spectrometry (EC-MS) was used to study the oxidation processes of ciprofloxacin (CIP), norfloxacin (NOR) and ofloxacin (OFL). Eight oxidation products for each parent compound were identified and their chemical structures were elucidated. The transformation trend of each product, with the continuous increase of voltage from 0 to 3000 mV, was recorded by online EC-MS. The oxidation pathways were proposed based on the structural information and transformation trends of oxidation products. We found the oxidation mechanisms of FQs consisted of the hydroxylation and cleavage of piperazinyl ring via reactions with hydroxyl radicals, while the fluoroquinolone core remained intact. The antibacterial activity of the parent compounds and their oxidation mixtures was estimated using zone inhibition tests for gram-negative bacteria Salmonella typhimurium. It was found that the oxidation mixtures of CIP and NOR retained the antibacterial properties with lower activity compared to their parent compounds, while the antibacterial activity of OFL was almost eliminated after oxidation. Furthermore, the toxicity of the three FQs and their oxidation mixtures were evaluated using algal growth inhibition test (Desmodesmus subspicatus). The median effective concentration (EC50) values for the algal inhibition tests were calculated for the end point of growth rate. The toxicity of CIP and NOR to green algae after electrochemical oxidation, remained unchanged, while that of OFL significantly increased. The results presented in this paper contribute to an understanding of the electrochemical oxidation mechanisms of FQs, and highlight the potential environmental risks of FQs after electrochemical oxidation processes.

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“…In this context, recent works showed that beside the parent drugs also their photoproducts exert antimicrobial activity, contributing to stimulate bacterial resistance (De Bel et al, 2009;Kusari et al, 2009;Sturini et al, 2012b;Sukul et al, 2009).…”

Section: Introductionmentioning

confidence: 99%