Degradation of the antibiotic oxolinic acid by photocatalysis with TiO2 in suspension

Giraldo, Ana L.; Peñuela, Gustavo A.; Torres-Palma, Ricardo A.; Pino, Nancy J.; Palominos, Rodrigo A.; Mansilla, Héctor D.

doi:10.1016/j.watres.2010.05.011

Cited by 184 publications

(76 citation statements)

References 49 publications

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“…[42] Similar findings were reported for the antibiotic oxolinic acid, where an increase above 1 g L À1 led to a decrease in the API removal. [43] Although the highest photocatalytic efficiency was achieved with 0.01 g L À1 , further experiments were carried out with the mid-level concentration of 0.1 g L À1 . This concentration is commonly applied with TiO 2 P25, although loadings can vary from 0.1 to 5.0 g L À1 .…”

Section: Resultsmentioning

confidence: 99%

Photolysis and TiO2-catalysed degradation of diclofenac in surface and drinking water using circulating batch photoreactors

Kanakaraju¹,

Cherie²,

Motti³

et al. 2014

Environ. Chem.

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Environmental context. Diclofenac, a common non-steroidal anti-inflammatory drug, is not completely removed from surface and drinking water by conventional treatment methods. Consequently, this drug is present in the aquatic environment and has been subsequently linked to toxic effects on organisms. We show that photolysis and TiO 2 -catalysed degradation in circulating batch reactors efficiently results in diclofenac removal under a variety of conditions. These photochemical methods thus may lead to more effective water treatment processes.Abstract. The occurrence of diclofenac (DCF) as an emerging pollutant in surface waters and drinking water has been attributed to elevated global consumption and the inability of sewage treatment plants to remove DCF. In this study, DCF spiked drinking water and river water was subjected to photolysis and TiO 2 photocatalytic treatments in a circulating laboratory-scale (immersion-well) and a demonstration-scale loop reactor (Laboclean). The operational parameters for the immersion-well reactor were optimised as follows: TiO 2 P25 loading, 0.1 g L À1 ; natural pH, 6.2; initial concentration, 30 mg L À1 ; water type, distilled water. Complete DCF removal was realised within 15 min under the optimised conditions using the immersion-well reactor. Sunlight-mediated photochemical degradation required a prolonged exposure period of up to 360 min for complete DCF removal. DCF in distilled and drinking water was efficiently degraded in the larger Laboclean reactor. Differences were, however, observed based on their pseudo-first-order rate constants, which implies that the water matrix has an effect on the degradation rate. Six major photoproducts, 2-(8-chloro-9H-carbazol-1-yl)acetic acid, 2-(8-hydroxy-9H-carbazol-1-yl)acetic acid, 2,6-dichloro-N-o-tolylbenzenamine, 2-(phenylamino)benzaldehyde, 1-chloromethyl-9H-carbazole and 1-methyl-9H-carbazole, generated from TiO 2 photocatalysis of DCF were identified by liquid chromatography-mass spectrometry (LCMS) and Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS). This work has shown that photocatalytic degradation kinetics of DCF are dependent on both the geometry of the photoreactor and the nature of the water matrices.

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Section: Resultsmentioning

confidence: 99%

Photolysis and TiO2-catalysed degradation of diclofenac in surface and drinking water using circulating batch photoreactors

Kanakaraju¹,

Cherie²,

Motti³

et al. 2014

Environ. Chem.

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“…66,68,73,85,93,[95][96][97]101,103,106,107,[128][129][130] As estruturas dos possíveis produtos formados são propostas baseando-se na composição elementar dos fármacos e mecanismos de reações orgânicas apresentados na literatura especializada. Salienta-se que a identificação dos produtos formados durante os processos de degradação é uma etapa bastante trabalhosa devido às baixas concentrações em que esses intermediários se encontram.…”

Section: Intermediários Formadosunclassified

“…Os autores demonstraram que reações com Ÿ OH provavelmente promovem também a remoção do átomo de flúor ligado ao C-6 das fluoroquinolonas avaliadas. Giraldo et al, 95 em seus estudos de degradação do ácido oxolínico por fotocatálise, relataram que o processo de hidroxilação das quinolonas deve ocorrer por reações do tipo photo-Kolbe, resultando na substituição do grupo carboxila (COOH) ligado ao C-3 por um próton ou uma hidroxila. Sirtori et al, 63,103 An et al, 97 Rodrigues-Silva et al, [106][107] Liu et al 133 propuseram que, durante a ozonização, a principal rota de degradação da ciprofloxacina, norfloxacina e lomefloxacina ocorre na região alcalina (N-1 e/ou anel piperazínico) dessas fluoroquinolonas.…”

Section: Intermediários Formadosunclassified

“…[76][77][78]85,95,96,106,107,135 Destaca-se que essa avaliação é de fundamental importância, uma vez que, mesmo o composto sendo altamente degradado, os intermediários formados podem apresentar atividade biológica. Com os ensaios de atividade antimicrobiana, é possível prever possíveis impactos no meio ambiente.…”

Section: Toxicidade E Atividade Antimicrobiana Residual Toxicidadeunclassified

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Occurrence and Degradation of Quinolones by Advanced Oxidation Processes

Rodrigues-Silva¹,

Maniero²,

Peres³

et al. 2014

Química Nova

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OCCURRENCE AND DEGRADATION OF QUINOLONES BY ADVANCED OXIDATION PROCESSES. In this review, the presence of quinolones in the environment, their risks and the available processes for water decontamination were addressed. Their occurrence in surface waters and also in soil raises concerns about the risk of the development of resistant bacteria and other potential chronic effects. AOPs (UV/H 2 O 2 , Fenton, photo-Fenton, and UV/TiO 2 ) and ozonation proved effective for degrading these emerging contaminants due to hydroxyl radical formation, surpassing the efficacy of conventional methods. In addition, the main degradation mechanisms of these drugs as well as data on residual biological activity were analyzed.Keywords: antimicrobials; degradation mechanisms; toxicity. INTRODUÇÃOAntimicrobianos são definidos como compostos naturais, sinté-ticos ou semi-sintéticos, cuja finalidade é prevenir ou tratar doenças infecciosas causadas por micro-organismos patogênicos, 1 tanto nos seres humanos como na medicina veterinária. Visto que não são totalmente metabolizados durante o uso terapêutico, os antimicrobianos estão presentes no esgoto doméstico principalmente como resultado da excreção humana. O uso de antimicrobianos na atividade pecuária contribui, também, para a sua introdução no meio ambiente, como resultado de processos de manufatura, disposição irregular ou excreção metabólica.2 Dessa forma, esses compostos são continuamente lançados no ambiente e, considerando sua característica recalcitrante de difícil remoção/degradação, são considerados pseudopersistentes.Existem aproximadamente onze diferentes classes de antimicrobianos, 3 que se diferenciam por sua estrutura química ou mecanismos de ação no tratamento específico de determinado patógeno. As quinolonas, antimicrobianos sintéticos, são eficientes no tratamento de infecções por bactérias Gram-positivas e Gram-negativas e são largamente empregadas tanto na medicina humana como veteriná-ria. Bactérias Gram-negativas são aquelas que possuem uma parede celular com poucas camadas de peptideoglicana e uma segunda membrana de lipopolissacarídeo. No processo de coloração, a lavagem com álcool rompe a camada externa de lipopolissacarídeo e o corante é removido por meio da camada de peptideoglicana. Consequentemente, as células Gram-negativas permanecem incolores até serem coradas com a safranina (segundo corante), adquirindo tonalidade rosa-avermelhada. Como exemplo, pode-se citar: Pseudomonas aeruginosa (causadora de infecções no aparelho pulmonar, urinário e respiratório), Escherichia coli (causadora de infecções urinárias) e Salmonella (causadora de intoxicações alimentares). As bactérias Gram-positivas, como por exemplo, a Streptococcus pneumoniae, possuem uma parede com mais camadas de peptideoglicana que as bactérias Gram-negativas. Empregando-se a coloração de Gram, apresentam-se com coloração púrpura quando fixadas com cristal violeta (primeiro corante), uma vez que essas bactérias retêm esse corante mesmo quando expostas ao álcool. 4,5 Dentre os principais riscos ...

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“…Advanced Oxidation Processes (AOPs) are physicochemical techniques (De la Cruz et al, 2013Rubio-Clemente et al, 2014), which have been applied to treat organic pollutants in both drinking water and wastewater (De la Cruz et al, 2013;Giraldo et al, 2010;Guzman-Duque et al, 2011;Velegraki and Mantzavinos, 2015). AOPs are characterized by the formation of oxidative species, mainly the hydroxyl radical ( OH), which degrades organic compounds with high reaction rates (Glaze et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

Selecting the best AOP for isoxazolyl penicillins degradation as a function of water characteristics: Effects of pH, chemical nature of additives and pollutant concentration

Villegas-Guzmán

Silva-Agredo

Flórez

et al. 2017

Journal of Environmental Management

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a b s t r a c tTo provide new insights toward the selection of the most suitable AOP for isoxazolyl penicillins elimination, the degradation of dicloxacillin, a isoxazolyl penicillin model, was studied using different advanced oxidation processes (AOPs): ultrasound (US), photo-Fenton (UV/H 2 O 2 /Fe 2þ ) and TiO 2 photocatalysis (UV/TiO 2 ). Although all processes achieved total removal of the antibiotic and antimicrobial activity, and increased the biodegradability level of the solutions, significant differences concerning the mineralization extend, the pH of the solution, the pollutant concentration and the chemical nature of additives were found. UV/TiO 2 reached almost complete mineralization; while~10% mineralization was obtained for UV/H 2 O 2 /Fe 2þ and practically zero for US. Effect of initial pH, mineral natural water and the presence of organic (glucose, 2-propanol and oxalic acid) were then investigated. UV/H 2 O 2 /Fe 2þ and US processes were improved in acidic media, while natural pH favored UV/TiO 2 system. According to both the nature of the added organic compound and the process, inhibition, no effect or enhancement of the degradation rate was observed. The degradation in natural mineral water showed contrasting results according to the antibiotic concentration: US process was enhanced at low concentration of dicloxacillin followed by detrimental effects at high substrate concentrations. A contrary effect was observed during photo-Fenton, while UV/TiO 2 was inhibited in all of cases. Finally, a schema illustrating the enhancement or inhibiting effects of water matrix is proposed as a tool for selecting the best process for isoxazolyl penicillins degradation.

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Degradation of the antibiotic oxolinic acid by photocatalysis with TiO2 in suspension

Cited by 184 publications

References 49 publications

Photolysis and TiO2-catalysed degradation of diclofenac in surface and drinking water using circulating batch photoreactors

Photolysis and TiO2-catalysed degradation of diclofenac in surface and drinking water using circulating batch photoreactors

Occurrence and Degradation of Quinolones by Advanced Oxidation Processes

Selecting the best AOP for isoxazolyl penicillins degradation as a function of water characteristics: Effects of pH, chemical nature of additives and pollutant concentration

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