VANESSA HONDA OGIHARA
2 resultados
Resultados de Busca
Agora exibindo 1 - 2 de 2
Artigo IPEN-doc 22417 Degradation and acute toxicity removal of the antidepressant fluoxetine (Prozac) in aqueous systems by electron beam irradiation2016 - SILVA, VANESSA H.O.; BATISTA, ANA P. dos S.; TEIXEIRA, ANTONIO C.S.C.; BORRELY, SUELI I.Electron beam irradiation (EBI) has been considered an advanced technology for the treatment of water and wastewater, whereas very few previous investigations reported its use for removing pharmaceutical pollutants. In this study, the degradation of fluoxetine (FLX), an antidepressant marketed as Prozac(Ā®), was investigated by using EBI at FLX initial concentration of 19.4 Ā± 0.2 mg L(-1). More than 90 % FLX degradation was achieved at 0.5 kGy, with FLX below the detection limit (0.012 mg L(-1)) at doses higher than 2.5 kGy. The elucidation of organic byproducts performed using direct injection mass spectrometry, along with the results of ion chromatography, indicated hydroxylation of FLX molecules with release of fluoride and nitrate anions. Nevertheless, about 80 % of the total organic carbon concentration remained even for 7.5 kGy or higher doses. The decreases in acute toxicity achieved 86.8 and 9.6 % for Daphnia similis and Vibrio fischeri after EBI exposure at 5 kGy, respectively. These results suggest that EBI could be an alternative to eliminate FLX and to decrease residual toxicity from wastewater generated in pharmaceutical formulation facilities, although further investigation is needed for correlating the FLX degradation mechanism with the toxicity results.Artigo IPEN-doc 20712 Photolysis of atrazine in aqueous solution: role of process variables and reactive oxygen species2014 - SILVA, MARCELA P.; BATISTA, ANA P. dos S.; BORRELY, SUELI I.; SILVA, VANESSA H.O.; TEIXEIRA, ANTONIO C.S.C.Photochemical advanced oxidation processes have been considered for the treatment of water and wastewater containing the herbicide atrazine (ATZ), a possible human carcinogen and endocrine disruptor. In this study, we investigated the effects of the photon emission rate and initial concentration on ATZ photolysis at 254 nm, an issue not usually detailed in literature. Moreover, the role of reactive oxygen species (ROS) is discussed. Photon emission rates in the range 0.87Ć1018ā3.6Ć1018 photons Lā1 s ā1 and [ATZ]0=5 and 20 mg Lā1 were used. The results showed more than 65 % of ATZ removal after 30 min. ATZ photolysis followed apparent first-order kinetics with k values and percent removals decreasing with increasing herbicide initial concentration. A fivefold linear increase in specific degradation rate constants with photon emission rate was observed. Also, regardless the presence of persistent degradation products, toxicity was efficiently removed after 60-min exposure to UV radiation. Experiments confirmed a noticeable contribution of singlet oxygen and radical species to atrazine degradation during photolysis. These results may help understand the behavior of atrazine in different UV-driven photochemical degradation treatment processes.