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Search Results: 1 - 10 of 344345 matches for " Sérgio Francisco Aquino "
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High Resolution Mass Spectrometry Elucidation of Captopril’s Ozonation and Chlorination By-Products  [PDF]
Frederico Jehár Oliveira Quint?o, Geraldo Célio Brand?o, Silvana de Queiroz Silva, Sérgio Francisco Aquino, Robson José de Cássia Franco Afonso
American Journal of Analytical Chemistry (AJAC) , 2017, DOI: 10.4236/ajac.2017.84020
Abstract: The article evaluated the degradation of the captopril in aqueous solution after ozonation and chlorination. The process was continuously monitored focusing on the identification, mass spectrometry and elucidation of its by-products by applying direct infusion and high performance liquid chromatography, electrospray ionization high resolution mass spectrometry, in the negative ion mode. The cytotoxicity of its by-products solutions were evaluated with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. It was observed through that after 30 min of ozonation and chlorination, there was complete oxidation of captopril, i.e., 100% removal efficiency. At these conditions, the rate of mineralization, by total organic carbon, was only 7.63% for ozonation and 6.40% for chlorination, evidencing the formation of degradation by-products. Ten captopril by-products were identified and their respective chemical structures elucidations are proposed. The treated samples and their by-products were nontoxic to HepG2 cells by MTT assay.
Influência da redu??o do tamanho de partículas na taxa de hidrólise de esgoto bruto doméstico
Teixeira, Ana Raquel;Chernicharo, Carlos Augusto de Lemos;Aquino, Sérgio Francisco;
Engenharia Sanitaria e Ambiental , 2008, DOI: 10.1590/S1413-41522008000400009
Abstract: the work aimed at assessing the changes in the particulate material conversion rates of domestic raw sewage, after passing through a pre-treatment unit that used the forced sieving through metallic sieves with apertures of 1.0 and 0.5 mm as strategy to reduce particles' size. the results indicated that the forced sieving and the reduction of particle size were not enough to increase the particulate material hydrolysis rates, since the hydrolysis constants for the raw and sieved sewage, estimated by the first order relation kinetics, analyzing the volatile suspended solids parameter, had similar values, in order of 0.0492 ± 0.0147 d-1, for the raw sewage, and of 0.0472 ± 0.0079 d-1 and 0.0470 ± 0.00117 d-1, for the raw sewage sieved in metallic sieves with apertures of 1.0 and 0.5 mm, respectively.
Caracteriza??o de contaminantes presentes em sistemas de tratamento de esgotos, por cromatografia líquida acoplada à espectrometria de massas tandem em alta resolu??o
Leite, Gustavo de Sousa;Afonso, Robson José de Cássia Franco;Aquino, Sérgio Francisco de;
Química Nova , 2010, DOI: 10.1590/S0100-40422010000300044
Abstract: this work shows results on the characterization, by liquid chromatography coupled to high resolution tandem mass spectrometry (lc-it-tof-ms) with electrospray ionization, of organic compounds present in raw and treated effluents from a combined sewage treatment systems (upflow anaerobic sludge blanket-trickling filter). the sewage samples were prepared by c18 solid phase extraction and the spectra obtained from the various extracts were submitted to principal component analysis to evaluate their pattern and identify the major deprotonated species. some target compounds were submitted to semiquantitative analysis, using phenolphtalein as internal standard. the results showed the anaerobic step had little impact on the removal of anionic surfactants (las), fatty acids, and some contaminantes such as bisphenol a and bezafibrate, whereas the aerobic post-treatment was very efficient in removing these organics.
Ozonólise das ligninas organossolve e kraft eucalipto. Parte II: cinética nos meios ácido e básico
Nascimento, Evandro A.;Morais, Sérgio A. L.;Aquino, Francisco J. T.;Piló - Veloso, Dorila;
Química Nova , 1998, DOI: 10.1590/S0100-40421998000500009
Abstract: organosolv and kraft lignins were treated with ozone both in basic and acid media and the reaction was studied kinetically. in contrast to reported studies, ozone was more efective in basic medium. kraft lignin was degraded faster than organosolv lignin in both media but in the basic medium the rate of reaction was very much faster than in the acid one: for kraft lignin, the observed degradation was 93% for 2 min of reaction in the basic medium and 56% for 10 min of reaction in the acid medium; for organosolv lignin, 47% and 25%, respectively, in the same times. higher phenolic hydroxyl groups contents increase the reaction rate.
Ozonólise das ligninas organossolve e kraft eucalipto. Parte II: cinética nos meios ácido e básico
Nascimento Evandro A.,Morais Sérgio A. L.,Aquino Francisco J. T.,Piló - Veloso Dorila
Química Nova , 1998,
Abstract: Organosolv and kraft lignins were treated with ozone both in basic and acid media and the reaction was studied kinetically. In contrast to reported studies, ozone was more efective in basic medium. Kraft lignin was degraded faster than organosolv lignin in both media but in the basic medium the rate of reaction was very much faster than in the acid one: for kraft lignin, the observed degradation was 93% for 2 min of reaction in the basic medium and 56% for 10 min of reaction in the acid medium; for organosolv lignin, 47% and 25%, respectively, in the same times. Higher phenolic hydroxyl groups contents increase the reaction rate.
Avalia??o da biodegradabilidade anaeróbia de lixiviados de aterro sanitários
Amaral, Míriam Cristina Santos;Ferreira, Cynthia Fantoni Alves;Lange, Liséte Celina;Aquino, Sérgio Francisco de;
Engenharia Sanitaria e Ambiental , 2008, DOI: 10.1590/S1413-41522008000100006
Abstract: the objectives of this article were to investigate the favorable environment and operational conditions to the development of the anaerobic biodegradability test for landfill leachate. the evaluated conditions were the relation food/microrganismo (a/m), seed acclimatization, and toxicity due to high ammonia concentration. the results indicated that a/m relation equivalent to 0,45 was presented as most favorable to the accomplishment of the test, and that the seed used presented good capacity of adaptation to the leachate, not demanding previous acclimatization. the leachate in question presented relatively low anaerobic biodegradability, and associated to the results of previous studies of aerobic biodegradability suggest that a significant fraction of organic substance is refractory to the aerobic and anaerobic metabolism, indicating that the physical-chemical treatment must be used as form of pre or post-treatment.
Biometaniza??o seca de resíduos sólidos urbanos: estado da arte e análise crítica das principais tecnologias
Gomes, Felipe Correia de Souza Pereira;Aquino, Sérgio Francisco de;Colturato, Luis Felipe de Dornfeld Braga;
Engenharia Sanitaria e Ambiental , 2012, DOI: 10.1590/S1413-41522012000300006
Abstract: the employment of anaerobic digestion technology (biomethanation) for the management of the organic fraction of municipal solid waste is a reality that has been spreading out all around the world. the dry biomethanation, in particular, has been highlighted due to its biological system higher robustness and to the low generation of liquid effluents. in order to assess the dry biomethanation technologies performance, technical visits were carried out at different plants representing the major technologies available - valorga, laran, kompogas, and dranco - and, based on in situ observations as well as on projected performance data, it was developed an assessment methodology, composed by 35 indexes, divided into 4 groups: historic; operational aspects; projected performance; real performance. after all, the best performance was presented by technologies referred to as 4 and 2 that employs rectangular horizontal digesters stirred by impellers with axis across the flux of the digesting material.
Uso de extrato de levedura como fonte de carbono e de mediadores redox, para a degrada??o anaeróbia de corante azo
Corrêa, Cássia Aparecida Rabelo;Aquino, Sérgio Francisco de;Caldas, Paula Cristina de Paula;Silva, Silvana de Queiroz;
Engenharia Sanitaria e Ambiental , 2009, DOI: 10.1590/S1413-41522009000400016
Abstract: this paper investigated the influence of using yeast extract, which is the source of redox mediators riboflavin and nicotinamide, in the decolorization of solutions containing the azo dye drimaren blue hf-rl in anaerobic conditions. it involved the incubation of serum bottles kept at 25 oc and inoculated with the azo-dye, and anaerobic sludge in the presence and absence of carbon source (glucose or yeast extract) and redox mediators (riboflavin and yeast extract). the monitoring of color, chemical oxygen demand (cod) and volatile fatty acids (vfa) showed that the addition of yeast extract (0.5 g/l) resulted in 80 to 85% color removal in the first 24 hours of incubation; and that the metabolites of dye degradation were toxic to the anaerobic microorganisms, which led to low cod removal efficiencies either in the presence or absence of yeast extract. the results also showed that the efficiencies of color removal were below 30% in the presence of only glucose or riboflavin, indicating that the yeast extract acted simultaneously as source of carbon and redox mediators.
Biometaniza o seca de resíduos sólidos urbanos: estado da arte e análise crítica das principais tecnologias Dry biomethanation of municipal solid waste: state-of-the-art and critical analysis of major technologies
Felipe Correia de Souza Pereira Gomes,Sérgio Francisco de Aquino,Luis Felipe de Dornfeld Braga Colturato
Engenharia Sanitaria e Ambiental , 2012,
Abstract: A utiliza o da tecnologia de digest o anaeróbia (biometaniza o) para a gest o da fra o organica dos resíduos sólidos urbanos é uma realidade que vem se disseminando mundialmente. Os sistemas via seca vem se destacando pela maior robustez do sistema biológico e pela minimiza o da gera o de efluentes líquidos. Para avaliar o desempenho de sistemas de digest o via seca, foram realizadas visitas técnicas a plantas das principais tecnologias - Valorga, Laran, Kompogas e Dranco - e, a partir de constata es in loco e de dados levantados junto aos fabricantes, elaborou-se uma metodologia para avalia o das mesmas, com 35 indicadores, divididos em 4 grupos (Histórico; Aspectos Operacionais; Desempenho de Projeto; Desempenho Real). Na soma ponderada, as tecnologias que obtiveram os dois melhores desempenhos foram aquelas denominadas de 4 e 2, respectivamente, que empregam digestor retangular horizontal com agita o mecanica por pás com eixo no sentido transversal ao fluxo do material em digest o. The employment of anaerobic digestion technology (biomethanation) for the management of the organic fraction of municipal solid waste is a reality that has been spreading out all around the world. The dry biomethanation, in particular, has been highlighted due to its biological system higher robustness and to the low generation of liquid effluents. In order to assess the dry biomethanation technologies performance, technical visits were carried out at different plants representing the major technologies available - Valorga, Laran, Kompogas, and Dranco - and, based on in situ observations as well as on projected performance data, it was developed an assessment methodology, composed by 35 indexes, divided into 4 groups: Historic; Operational Aspects; Projected Performance; Real Performance. After all, the best performance was presented by technologies referred to as 4 and 2 that employs rectangular horizontal digesters stirred by impellers with axis across the flux of the digesting material.
Compostos bioativos e atividade antioxidante do café conilon submetido a diferentes graus de torra
Morais, Sérgio Ant?nio Lemos de;Aquino, Francisco José T?rres de;Nascimento, Priscilla Mendes do;Nascimento, Evandro Afonso do;Chang, Roberto;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000200011
Abstract: the bioactive compounds and antioxidant activity presented by conilon coffee (c. canephora) variety, produced in the espírito santo state, brazil, were quantified. the light roast coffee showed the highest level of total phenols, trigonelline, caffeic and chlorogenic acids. the proanthocyanidin level was the highest for dark roast coffee, while caffeine level didn't show significative changes for the light and middle roast coffees. all the conilon coffee extracts showed antioxidant activity depending on bioactive compounds concentration and roasting degree. the coffee samples submitted to a light roasting degree showed the highest antioxidant activity.
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