Decomposition of diclofenac by solar driven photocatalysis at pilot plant scale

Pérez-Estrada, Leónidas A.; Maldonado, Manuel I.; Gernjak, Wolfgang; Agüera, Ana; Fernández‐Alba, Amadeo R.; Martín, M.M. Ballesteros; Malato, Sixto

doi:10.1016/j.cattod.2005.03.013

Cited by 143 publications

(68 citation statements)

References 36 publications

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“…This may be attributed to the insolubility of DCF in water at pH 3, as DCF is known to become practically insoluble below a pH of 4. [50] DCF degradation studies conducted with other AOPs such as photo-Fenton and ozonation have also been conducted under slightly acidic conditions (pH 5.0-6.0). [28,50,51] The adsorption decreased to 20.2 % at pH 5 and then to 6.5 % at pH 11, because of the electrostatic repulsion effects of the negatively charged DCF and the TiO 2 surface.…”

Section: Resultsmentioning

confidence: 99%

“…[49] The pK a value of DCF (carboxyl group) is known to be 4.15 (at 25 8C). [50] At a pH , pK a , DCF is present in its neutral or protonated form, whereas at a pH . pK a it predominantly exists in deprotonated form, i.e.…”

Section: Resultsmentioning

confidence: 99%

“…[20,21] In particular, DCF has displayed the highest acute toxicity in comparison to other NSAIDs. [22] A concentration of 11 454 mg L À1 was reported to cause 50 % of effect (EC 50 ) on the Microtox system over 30 min. [23] Its removal efficiencies also greatly vary between 0 and 80 % depending on the operating conditions of WWTPs such as sunlight exposure or acidic conditions.…”

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: 99%

Section: Resultsmentioning

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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“…4 Diclofenac is considerably stable under normal environmental conditions and the most probable decomposition pathway for its onsite elimination is photodecomposition. [5][6][7][8] Investigation of the photolysis of labile environmental pharmaceutical contaminants is important in environmental chemistry because it presents basic data on their fates and persistence in natural environments exposed to sunlight action. 9 Cyclodextrins (CDs) are cyclic oligosaccharides made up of six to eight α-D-glucose units connected through glycosidic-α-1,4-bonds.…”

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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“…A Tabela 1 compara a redução da carga orgânica em função da corrente aplicada. 21,22 Comparando a Figura 7 com as reduções da DQO da Tabela 1, nota-se que a carga orgânica foi oxidada, porém sua concentração decai tabela 1. [16][17][18][19][20][21] Comparando os resultados da degradação Fenton/eletroquímica do diclofenaco sódico, onde o fármaco se oxida via • OH catalisado pela presença de íon ferroso e na superfície do anodo, ocorre o decaimento quase total da sua concentração (degradação de 99,4% em 4 A), porém a diminuição da DQO não acompanha esse efeito, pois mostra um relativo decaimento da demanda de oxigênio (63,2% em 4 A), estes resultados mostram que a degradação forma sub-produtos, que não são identificados na CLAE, nas condições de análise.…”

Section: Estudo Da Degradação Do Diclofenaco Sódicounclassified

Avaliação da degradação do diclofenaco sódico utilizando H2O2/fenton em reator eletroquímico

Rocha¹,

Beati²,

Oliveira³

et al. 2009

Quím. Nova

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Recebido em 29/2/08; aceito em 26/9/08; publicado na web em 5/2/09 EVALUATION OF THE DEGRADATION OF SODIUM DICLOFENAC USING H 2 O 2 /FENTON IN ELECTROCHEMICAL REACTOR. This paper describes a degradation study of the anti-inflammatory sodium diclofenac in aqueous medium using an electro-chemical flow reactor with a gas diffusion electrode as cathode. Two degradation processes were compared: by H 2 O 2 electrogenerated and H 2 O 2 electro-generated/Fe(II). Concentration of sodium diclofenac was determined during the experiments by HPLC. The changes in chemical oxigen demand (COD) were also evaluated. Under the specific reaction conditions, 350 mg L -1 of H 2 O 2 was electro-generated and 99.2% of sodium diclofenac was degradated, with 27.4% COD reduction. At the same conditions, but using Fe(II), drug degradation was 99.4% and the COD reduction was 63.2%.Keywords: sodium diclofenaco; electrochemical reactor; gas diffusion electrode. introduçãoA indústria farmacêutica ocupa um lugar de destaque, tanto no âmbito nacional quanto no internacional, quanto ao volume de recursos destinados ao desenvolvimento de novos fármacos e a sistemas de produção mais eficientes. Anualmente são produzidas grandes quantidades de produtos farmacêuticos com aplicação nas mais diversas áreas da saúde humana e animal, sendo que a maioria dos princípios ativos utilizados é de compostos orgânicos biologicamente ativos.Considerando que os processos de produção mais modernos são planejados para maximizar a produção e minimizar a geração de resíduos ou efluentes líquidos, as operações de manutenção e limpeza das áreas de fabricação e equipamentos geram efluentes líquidos que necessitam de um tratamento adequado antes de serem descartados no meio ambiente. Outra fonte de efluentes é o processo de inutilização e/ou destruição de lotes de medicamentos com prazos de validade vencidos, que são recolhidos do mercado.Um exemplo de princípio ativo largamente comercializado é o diclofenaco sódico, um fármaco não-esteróide com pronunciadas propriedades anti-reumática, anti-inflamatória, analgésica e antipirética. Este fármaco é um dos princípios ativos mais vendido no Brasil e esse grande consumo é devido a uma ampla diversidade de aplicações, que vão desde o tratamento pós-operatório até o tratamento pós-traumático da dor. 1,2 O grande consumo do diclofenaco sódico, sua diversificada forma de apresentação e sua variada fonte de geração de resíduos dentro da indústria, torna o estudo da degradação desse composto ativo e o conseqüente tratamento das águas residuárias da indústria farmacêutica de grande importância, devido ao impacto que esses compostos biologicamente ativos causam no meio ambiente. Para controle desses compostos ativos existentes nos despejos da indústria farmacêutica, existem vários processos de tratamento de efluentes aquosos que podem ser utilizados, como o tratamento químico, biológico e a incineração do efluente.As dificuldades observadas no tratamento usual de compostos da indústria farmacêutica abrem precedentes para a utilização ...

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Decomposition of diclofenac by solar driven photocatalysis at pilot plant scale

Cited by 143 publications

References 36 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

Avaliação da degradação do diclofenaco sódico utilizando H2O2/fenton em reator eletroquímico

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