Artigo de peri??dico
Degradation of diclofenac by electron beam irradiaton: Toxicitiy removal, by-products identification and effect of another pharmaceutical compound
Registro en:
2213-3437
4
6
10.1016/j.jece.2018.06.065
aguardando
Sem Percentil
81.50
Autor
TOMINAGA, FLAVIO K.
BATISTA, ANA P. dos S.
TEIXEIRA, ANTONIO C.S.C.
BORRELY, SUELI I.
Resumen
Water contamination by the anti-inflammatory drug diclofenac (DCF) is a consequence of its incomplete removal
in wastewater and sewage treatment plants, which is potentialized by interactions with other pharmaceutical
contaminants. In this context, electron beam irradiation (EBI) has been considered a clean technology for degrading
pharmaceutical compounds in water. Nevertheless, the identification of DCF by-products and their
correlation with biological recalcitrance and acute toxicity are poorly understood. In this study, the V. fischeri
test was used to characterize DCF toxicity in the absence and presence of fluoxetine (FLX), prior and after
irradiation. The results showed complete DCF degradation at low dose (5 kGy). DCF concentration followed
pseudo first-order decay with respect to the absorbed, with k0 = (1.33 ?? 0.10) kGy???1 (DCF) and k0 =
(0.90 ?? 0.12) kGy???1 (DCF+FLX). In contrast, negligible TOC removal was observed even at 7.5 kGy, with the
formation of recalcitrant, non-biodegradable by-products, as also suggested by the respirometry test. Despite
that, the toxicity of the DCF solution diminished from (19.6 ?? 1.6) TU to (6.2 ?? 2.3) TU, and from (6.8 ?? 0.9)
TU to (3.1 ?? 0.2) TU, in the absence and presence of FLX, respectively, after irradiation up to 5 kGy. Four of the
eleven by-products identified by direct-injection MS were easily degraded by EBI, and one (C13H14ClNO5) was
considered the least recalcitrant but the most toxic. Based on these results, a possible DCF degradation pathway
is proposed, involving hydroxylation and oxidation of aromatic rings, dehalogenation and C???N bond cleavage. Funda????o de Amparo ?? Pesquisa do Estado de S??o Paulo (FAPESP) Conselho Nacional de Desenvolvimento Cient??fico e Tecnol??gico (CNPq) FAPESP: 13/50218-2; 14/17996-4 CNPq: 152011/2016-1