FLAVIO KIYOSHI TOMINAGA
2 resultados
Resultados de Busca
Agora exibindo 1 - 2 de 2
Artigo IPEN-doc 30401 Emerging pollutants in textile wastewater2024 - GARCIA, VANESSA S.G.; TOMINAGA, FLAVIO K.; ROSA, JORGE M.; BORRELY, SUELI I.Water and several chemicals, including dyestuffs, surfactants, acids, and salts, are required during textile dyeing processes. Surfactants are harmful to the aquatic environment and induce several negative biological effects in exposed biota. In this context, the present study aimed to assess acute effects of five surfactants, comprising anionic and nonionic classes, and other auxiliary products used in fiber dyeing processes to aquatic organisms Vibrio fischeri (bacteria) and Daphnia similis (cladocerans). The toxicities of binary surfactant mixtures containing the anionic surfactant dodecylbenzene sulfonate + nonionic fatty alcohol ethoxylate and dodecylbenzene sulfonate + nonionic alkylene oxide were also evaluated. Nonionic surfactants were more toxic than anionic compounds for both organisms. Acute nonionic toxicity ranged from 1.3 mg/L (fatty alcohol ethoxylate surfactant) to 2.6 mg/L (ethoxylate surfactant) for V. fischeri and from 1.9 mg/L (alkylene oxide surfactant) to 12.5 mg/L (alkyl aryl ethoxylated and aromatic sulfonate surfactant) for D. similis, while the anionic dodecylbenzene sulfonate EC50s were determined as 66.2 mg/L and 19.7 mg/L, respectively. Both mixtures were very toxic for the exposed organisms: the EC50 average in the anionic + fatty alcohol ethoxylate mixture was of 1.0 mg/L ± 0.11 for V. fischeri and 4.09 mg/L ± 0.69 for D. similis. While the anionic + alkylene oxide mixture, EC50 of 3.34 mg/L for D. similis and 3.60 mg/L for V. fischeri. These toxicity data suggested that the concentration addition was the best model to explain the action that is more likely to occur for mixture for the dodecylbenzene sulfonate and alkylene oxide mixtures in both organisms. Our findings also suggest that textile wastewater surfactants may interact and produce different responses in aquatic organisms, such as synergism and antagonism. Ecotoxicological assays provide relevant information concerning hazardous pollutants, which may then be adequately treated and suitably managed to reduce toxic loads, associated to suitable management plans.Artigo IPEN-doc 28433 UVA/persulfate-driven nonylphenol polyethoxylate degradation2022 - NUNES, R.F.; TOMINAGA, F.K.; BORRELY, S.I.; TEIXEIRA, A.C.S.C.UV/persulfate (UV/PS) technologies have gained increased attention as efficient alternatives for removing pollutants from different classes, although processes based on the UVA-driven S2O2−8 (PS) activation have not yet been discussed in the literature for the removal of the nonionic surfactant nonylphenol polyethoxylate (NPEO). The present study investigated the simultaneous effect of the initial persulfate concentration ([PS]0) and specific photon emission rate (EP,0) on NPEO degradation by UVA/PS following a Doehlert experimental design. The results for [NPEO]0 = (4.65 ± 0.15) mg L−1 indicated more than 97.8% NPEO removal after 2 h, with pseudo first-order specific degradation rate (kobs) of 0.0320 min−1, for [PS]0 = 7.75 mmol L−1 and EP,0 = 0.437 μmol photons L−1 s−1. Under these conditions, NPEO half-life time was about 22 min, and the EC50-48 h (% v/v) values for Daphnia similis before and after treatment did not differ significantly. Higher values of EP,0 would influence NPEO removal for [PS]0 not higher than 8–10 mmol L−1, although lower degradation efficiencies were obtained with higher [NPEO]0 or real wastewater, except for longer reaction times. Additionally, UVA/PS showed to be efficient for tensoactivity removal, despite the negligible total organic carbon (TOC) removal achieved. Finally, UVC and UVA resulted in NPEO degradation higher than 96% and similar tensoactivity removals when UVA/PS was conducted under optimal conditions ([PS]0 = 10 mmol L−1; EP,0 = 0.324 μmol photons L−1 s−1), suggesting that UVA radiation available in solar light could be advantageously employed for NPEO removal at concentrations usually found in wastewater.