Photocatalytic degradation study of diclofenac over aqueous TiO2 suspensions

Calza, Paola; Sakkas, Vasilios A.; Medana, Claudio; Baiocchi, Claudio; Dimou, Aikaterini; Pelizzetti, Ezio; Albanis, Triantafyllos A.

doi:10.1016/j.apcatb.2006.04.021

Cited by 314 publications

(137 citation statements)

References 28 publications

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“…[39] Another study, however, reported an insignificant degradation efficiency upon direct photolysis. [34] These somewhat contradictory results may be attributed to differences in the radiation intensity from the chosen light sources and variations in the water matrices. [1] In particular, natural organic matter present in the water can compete for light absorption.…”

Section: Resultsmentioning

confidence: 93%

“…Inconsistencies in optimum TiO 2 loadings reported have been linked to the geometry of the chosen photoreactor and the nature of the compound under investigation. [44,45] Thus far, the optimal TiO 2 loading for DCF photocatalysis reported in related studies was 1, [41] 0.624 [34] and 0.25 g L À1 . [31] The much lower TiO 2 loading determined in this study can be attributed to the very effective circulation in the immersion-well setup chosen, which ensured optimal distribution of photocatalyst throughout the entire reaction mixture (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…For example, Mendez-Arriaga et al observed up to 75 % DCF degradation, [13] whereas Calza et al reported an insignificant photolysis of DCF. [34] Typical parameters, which control the photocatalytic behaviour of DCF, include TiO 2 loading, initial concentrations, effect of oxidants and water matrices. Despite this, there is little known about the photocatalytic treatment of DCF in drinking water (tap water, TW) although monitoring studies have highlighted the presence of this API in this water source.…”

Section: Introductionmentioning

confidence: 99%

“…[13,[30][31][32][33][34] Existing studies describing photolysis either in the laboratory or in the natural environment using sunlight have reported direct photolysis as the main depletion mechanism for DCF. Discrepancies have, however, arisen between studies on the effect of artificial UV light on DCF phototransformations.…”

Section: Introductionmentioning

confidence: 99%

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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: 93%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…1 Nowadays, this drug is ubiquitously present in the aquatic environment. 2 These contaminants are important because many of them are not degraded by the typical biological treatments applied in wastewater treatment plants and represent a continuous input into the environment.…”

Section: Introductionmentioning

confidence: 99%

Photochemical characteristics of diclofenac and its photodegradation of inclusion complexes with β-cyclodextrins

Qin¹,

Yang²,

Chen³

et al. 2012

Quím. Nova

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Recebido em 3/7/11; aceito em 29/9/11; publicado na web em 6/12/11 Diclofenac is one of most frequently detected compounds in the water cycle. In this work, the effect of initial concentration, liquid inclusion complexes with β-Cyclodextrins (β-CDs) on the photodegradation of diclofenac were studied. Six phototransformation products were detected by HPLC chromatograms. UV-absorption spectra of diclofenac and phototransformation products were determined. One of the phototransformation products was identified. The degradation followed pseudo-first-order kinetics. The experiment showed that irradiation of diclofenac in the presence of β-CDs increase photodegradation rate and determined the optimal molar ratio of diclofenac to β-CDs as 1:2. The reduced photohaemolytic activity of diclofenac in the presence of β-CDs may be attributed to the sequestering and stabilizing of the radical intermediates and /or photoproducts by complexation.

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Advanced Mass Spectrometry‐Based Techniques for the Identification and Structure Elucidation of Transformation Products of Emerging Contaminants

Calza

Fabbri

2014

Transformation Products of Emerging Contaminants in the Environment

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Photocatalytic degradation study of diclofenac over aqueous TiO2 suspensions

Cited by 314 publications

References 28 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

Photochemical characteristics of diclofenac and its photodegradation of inclusion complexes with β-cyclodextrins

Advanced Mass Spectrometry‐Based Techniques for the Identification and Structure Elucidation of Transformation Products of Emerging Contaminants

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