FLAVIO KIYOSHI TOMINAGA
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Artigo IPEN-doc 29630 Experimental design and bioassays as tools to investigate the impact of anodic oxidation on progestins degradation2023 - JESUS, JULIANA M.S. de; ARGOLO, ALLAN dos S.; TOMINAGA, FLAVIO K.; TAQUEDA, MARIA E.; BILA, DANIELE M.; BORRELY, SUELI I.; TEIXEIRA, ANTONIO C.S.C.The present study investigated the degradation of levonorgestrel (LNG) and gestodene (GES) through an anodic oxidation process mediated by active chlorine species. The independent variables [LNG]0 and [GES]0, current density (mA cm−2), and [NaCl]0 (mol L−1) were optimized through a response surface methodology (RSM) based on a four-level central composite design (CCD). Specific energy consumption allowed CCD-RSM analysis and optimization. The decay of progestins was followed to verify the kinetics of the anodic degradation process. Chlorine monitoring showed that excess Cl− concentration did not mean high hormones removal, as well as the excess of current density. Central point conditions ([NaCl]0 = 0.07 mol L−1, j = 32.5 mA cm−2, [LNG]0, and [GES]0 1.0 mg L−1) proved to be the best operational option. The performance with real pharmaceutical wastewater confirmed model optimization (2.2 ± 0.2 kWh g−1, with removals of 83.1 ± 0.9% and 75.1 ± 2.8% for LNG and GES, respectively). The selected condition was used for estrogenic activity and acute toxicity assays. The first allowed the identification of the initial estrogenic activity for the mixture of LNG and GES (924 E2-EQ ng L−1). Additionally, the electrochemical process could decrease this environmental parameter by 74.6%. The progestin mixture was classified as acute toxicity to Daphnia similis, with a toxicity unit (TU) of 2.5 100/EC50%. After electrolysis, the hormone solutions reached a fourfold increase in TU value, classified as high acute toxicity.Artigo IPEN-doc 28860 Radiolytic degradation of levonorgestrel and gestodene2022 - JESUS, JULIANA M.S. de; TOMINAGA, FLAVIO K.; ARGOLO, ALLAN dos S.; NASCIMENTO, ANA C.G.; BORRELY, SUELI I.; VIEIRA, DANIEL P.; BILA, DANIELE M.; TEIXEIRA, ANTONIO C.S.C.This study reports the feasibility of ionizing sources (60Co source and electron beam radiation) to degrade the progestins hormones levonorgestrel (LNG) and gestodene (GES) in synthetic solutions and real pharmaceutical wastewater (RPW). Doses of 0.5–100 kGy and dose rates of 2.5 and 10 kGy h−1 were applied. LNG was shown to be more recalcitrant than GES, with 90% removals achieved at doses around 7.7 kGy (LNG) and 1.6 kGy (GES) in model systems, with LNG showing greater reactivity with reducing species in γ-radiolyis, unlike GES. Furthermore, LNG removal remained around 60% in RPW at low doses, while more than 60% GES removal was observed for all doses. LNG and GES toxicities to Daphnia similis were absorbed dose-dependent, with low doses resulting in toxicity reductions of around 32% (LNG) and 42% (GES); in turn, high doses promoted a fourfold increase in toxicity. γ-radiolysis reduced the cytotoxic character of LNG to NIH-3T3-L1 cells, while non-irradiated or irradiated GES solutions did not exhibit any cytotoxic effect. Finally, the estrogenic activity, evaluated by the YES assay, was dose-dependent for both progestins, which may be related to the evolution of transformation products formed by water radiolysis in each case, decreasing for high doses.