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Search Results: 1 - 10 of 148997 matches for " Raquel F. Pupo; "
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Diesel degradation in soil by fenton process
Villa, Ricardo D.;Trovó, Alam G.;Nogueira, Raquel F. Pupo;
Journal of the Brazilian Chemical Society , 2010, DOI: 10.1590/S0103-50532010000600019
Abstract: this work reports the use of fenton process for diesel degradation and addresses common aspects of real situations that can affect the soil remediation efficiency. it was observed that most of diesel hydrocarbons containing less than 14 carbon atoms were lost by volatilization prior to the treatment. about 80% degradation was achieved in a loam soil, while less than 20% was observed in a clay loam soil. the multiple additions of h2o2 resulted in 80% diesel degradation, while only 14% of diesel was degraded after a reaction time of 80 h using a single addition. the addition of soluble iron was essential to achieve high degradation levels. no significant increase in diesel degradation (t-test; p = 0.05) was observed using h2o2 dosages between 0.09 and 0.36 g g-1. furthermore, the highest h2o2 dosage applied (0.36 g g-1) degraded around 87% of the organic matter originally present in the soil.
Comentário sobre a revis o "DDT: toxicidade e contamina o"
Nogueira Raquel F. Pupo,Torres Jo?o Paulo Machado
Química Nova , 2003,
Abstract:
Sistema de inje o em fluxo espectrofotométrico para monitorar peróxido de hidrogênio em processo de fotodegrada o por rea o foto-Fenton
Oliveira Mirela C.,Nogueira Raquel F. Pupo,Gomes Neto José A.,Jardim Wilson F.
Química Nova , 2001,
Abstract: A flow injection spectrophotometric system was projected for monitoring hydrogen peroxide during photodegradation of organic contaminants in photo-Fenton processes (Fe2+/H2O2/UV). Sample is injected manually in a carrier stream and then receives by confluence a 0.1 mol L-1 NH4VO3 solution in 0.5 mol L-1 H2SO4 medium. The product formed shows absorption at 446 nm which is recorded as a peak with height proportional to H2O2 concentration. The performance of the proposed system was evaluated by monitoring the consumption of H2O2 during the photodegradation of dichloroacetic acid solution by foto-Fenton reaction.
Photo-Fenton process for treating biological laboratory wastewater containing formaldehyde
Fonseca, Janaína Conrado L.;Nogueira, Raquel F. Pupo;Marchi, Mary Rosa Rodrigues;
Eclética Química , 2010, DOI: 10.1590/S0100-46702010000100003
Abstract: laboratories consume great amounts of hazardous chemicals substances and consequently generate wastewater containing them, for example formaldehyde. this substance is widely utilized to preserve biological samples generating many liters of this residue every year. the present work proposes the use of the photo-fenton process to treat formaldehyde wastewater using sunlight irradiation. some aspects were investigated such as the iron source, sample and hydrogen peroxide concentration and also the use of stirred systems. the use of ferrioxalate (0.5 mmol l-1) improved the efficiency of the process in relation to the use of iron nitrate, while at least 1.0 mol l-1 h2o2 is necessary to treat the sample of the 500 mg c l-1. under these conditions, every formaldehyde detectable was degradeted and 89% of the dissolved organic carbon was removed in two hours of exposure to sunlight. these results are satisfaction considerate for s?o paulo state environmental agency.
Avalia??o dos parametros de solubilidade de Hildebrand/Hansen na sele??o de solventes para a extra??o de pesticidas organoclorados do solo
Villa, Ricardo D;de Oliveira, Adriana P;Nogueira, Raquel F. Pupo;
Química Nova , 2011, DOI: 10.1590/S0100-40422011000900004
Abstract: this work evaluated the use of the hildebrand/hansen solubility parameters for selection of solvents for extraction of the organochlorine pesticides pp' ddt, pp' dde, aldrin and a-endossulfan from soil using columns packed with al2o3. the mixtures hexane:dichloromethane (7:3; v/v), hexane:acetonitrile (1:1; v/v), hexane:acetone (1:1; v/v) and pure hexane were chosen as extracting solutions. in the addition and recovery tests, different extraction solutions provided high recoveries percentages (>75%) with coefficients of variation below 15%. the recoveries are in agreement with the hildebrand/hansen parameters, demonstrating its applicability in the selection of extracting solution and in the replacement of toxic solvents, as dichloromethane
Potencial de aplica??o do processo foto-fenton/solar como pré-tratamento de efluente da indústria de laticínios
Villa, Ricardo Dalla;Silva, Milady R. Apolinário da;Nogueira, Raquel F. Pupo;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000800002
Abstract: dairy wastewater is characterized by frequent episodes of drastic increases of organic content, giving rise to bulking filamentous bacteria and compromising the biological treatment process. this study reports the reduction of organic content of such wastewater by the application of the solar photo-fenton process. for a wastewater containing 335, 2627 or 5400 mg c l-1 between 90% and 50% of the organic carbon content were removed after 3.5 h irradiation. the results show that the solar photo-fenton process can be a good alternative for the abatement of organic content of dairy wastewater, especially in cases of organic content fluctuation, allowing an efficient biological treatment.
Sistema de inje??o em fluxo espectrofotométrico para monitorar peróxido de hidrogênio em processo de fotodegrada??o por rea??o foto-Fenton
Oliveira, Mirela C.;Nogueira, Raquel F. Pupo;Gomes Neto, José A.;Jardim, Wilson F.;Rohwedder, Jarbas J. R.;
Química Nova , 2001, DOI: 10.1590/S0100-40422001000200007
Abstract: a flow injection spectrophotometric system was projected for monitoring hydrogen peroxide during photodegradation of organic contaminants in photo-fenton processes (fe2+/h2o2/uv). sample is injected manually in a carrier stream and then receives by confluence a 0.1 mol l-1 nh4vo3 solution in 0.5 mol l-1 h2so4 medium. the product formed shows absorption at 446 nm which is recorded as a peak with height proportional to h2o2 concentration. the performance of the proposed system was evaluated by monitoring the consumption of h2o2 during the photodegradation of dichloroacetic acid solution by foto-fenton reaction.
Fundamentos e aplica??es ambientais dos processos fenton e foto-fenton
Nogueira, Raquel F. Pupo;Trovó, Alam G.;Silva, Milady Renata A. da;Villa, Ricardo D.;Oliveira, Mirela C. de;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000200030
Abstract: wastewater and soil treatment processes based on fenton's reagent have gained great attention in recent years due to its high oxidation power. this review describes the fundaments of the fenton and photo-fenton processes and discusses the main aspects related to the degradation of organic contaminants in water such as the complexation of iron, the use of solar light as the source of irradiation and the most important reactor types used. an overview of the main applications of the process to a variety of industrial wastewater and soil remediations is presented.
Fotodegrada??o de fenol e clorofenóis por processo foto-Fenton mediado por ferrioxalato
Nogueira, Raquel Fernandes Pupo;Modé, Daniela Fonseca;
Eclética Química , 2002, DOI: 10.1590/S0100-46702002000200015
Abstract: the influence of some operational parameters such as stirring the solution during solar irradiation and the solution flow rate into artificial irradiation photoreactor were evaluated on the photodegradation of 2-chlorophenol (2cp) and 2,4-diclorophenol (dcp) by photo-fenton process mediated by ferrioxalate. after evaluation of these parameters, the systems were applied to photodegradation of phenol and mono (2-chlorophenol and 4-clorophenol), di (2,4-dichlorophenol) and tri (2,4,6-trichlorophenol) chlorophenols to evaluate the photodegradation efficiency of these compounds under solar as well as artificial irradiation. small differences in the percentages of total organic carbon (toc) removal and generation of chloride ions were observed with and without stirring the solution during solar irradiation of 2cp. under artificial irradiation, the increase of flow rate resulted in lower toc removal, while a higher rate of toc removal was obtained due to a shorter irradiation time. an intermediate flow rate of 33.4 ml min-1 was then used. under solar irradiation, 15 minutes irradiation were necessary for complete removal of all chlorophenols, however, the complete removal of phenol was achieved in 20 minutes. under artificial irradiation, the chlorophenols were removed between 4.5 and 6.5 minutes of irradiation. the degradation rates increased slightly with the increase of the number of chlorides bonded to the aromatic ring under solar as well as artificial irradiation.
Slimmer or Fertile? Pharmacological Mechanisms Involved in Reduced Sperm Quality and Fertility in Rats Exposed to the Anorexigen Sibutramine
Cibele S. Borges, Gabriela Missassi, Enio S. A. Pacini, Luiz Ricardo A. Kiguti, Marciana Sanabria, Raquel F. Silva, Thais P. Banzato, Juliana E. Perobelli, André S. Pupo, Wilma G. Kempinas
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066091
Abstract: Sperm acquire motility and fertility capacity during epididymal transit, under the control of androgens and sympathetic innervations. It is already known that the acceleration of epididymal sperm transit time can lead to lower sperm quality. In a previous work we showed that rats exposed to the anorexigen sibutramine, a non-selective serotonin-norepinephrine reuptake inhibitor, presented faster sperm transit time, lower epididymal sperm reserves and potentiation of the tension of epididymal duct to norepinephrine exposed acutely in vitro to sibutramine. In the present work we aimed to further investigate pharmacological mechanisms involved in these alterations and the impact on rat sperm quality. For this, adult male Wistar rats were treated with sibutramine (10 mg/kg/day) or vehicle for 30 days. Sibutramine decreased final body, seminal vesicle, ventral prostate and epididymal weights, as well as sperm transit time in the epididymal cauda. On the contrary of the in vitro pharmacological assays, in which sibutramine was added directly to the bath containing strips of distal epididymal cauda, the ductal tension was not altered after in vivo sub-chronic exposure to sibutramine. However, there is pharmacological evidence that the endogenous epididymal norepinephrine reserves were reduced in these animals. It was also shown that the decrease in prostate weight can be related to increased tension developed of the gland, due to sibutramine sympathomimetic effects. In addition, our results showed reduced sperm quality after in utero artificial insemination, a more sensitive procedure to assess fertility in rodents. The epididymal norepinephrine depletion exerted by sibutramine, associated with decreases in sperm transit time, quantity and quality, leading to reduced fertility in this experimental model, reinforces the concerns about the possible impact on fertility of man taking sibutramine as well as other non-selective serotonin-norepinephrine reuptake inhibitors, especially considering the lower reproductive efficiency of humans compared to males of other species.
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