72 resultados para Compostos voláteis orgânicos


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES

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The detection of emerging interest microcontaminants in environmental samples of surface water, groundwater, drinking water, wastewater and effluents from water and sewage treatment plants (WTP and STP), in many countries, suggests these pollutants are widespread in the environment, mainly in urban areas. This is a reason for great concern, since many of these compounds are potentially harmful for humans other living beings, and they are not efficiently removed in the majority of WTP and STP, which is exacerbated by precariousness of water supply and sanitation services. In Natal, like other Brazilian cities, the sewage system serves only part of the urban area (about 30%), so that the rest of the wastewater is infiltrated in the sandy soil of the region in cesspool-dry well systems. This has resulted in contamination of groundwater in the area (sand-dune barrier aquifer, which supplies more than 50% of the city population), which has been observed by the increase in nitrate concentration in supply wells. The vulnerability of the sanddune barrier aquifer, combined with reports of the presence of emerging interest microcontaminants in Brazil and worldwide, led to this research, which investigated the occurrence of fifteen microcontaminants in Natal groundwater and sewage. Samples were collected at five wells used for water supply, the raw sewage and the effluents from biological reactors from STP (UASB and activated sludge reactors). Two samples of each sample were taken, with one week apart between the samples. To determine the contaminants, extraction of aquifer water, and raw and treated sewage samples were performed, through the technique of using SPE Strata X cartridge (Phenomenex®) to the aquifer water, and Strata SAX and Strata X (Phenomenex® ) for samples of raw and treated sewage. Subsequently the extracts were analyzed using GC-MS technique. Much of the analyzed microcontaminants were detected in groundwater and sewage. The concentrations in groundwater are generally lower than those found in the sewers. Some of the compounds (estrone, estradiol, bisphenol A, caffeine, diclofenac, naproxen, paracetamol and ibuprofen) are partially removed at STP.

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Hancornia speciosa Gomes (Apocynaceae), popularly known as ‘mangabeira’, has been used in folk medicine to treat inflammatory disorders, hypertension, dermatitis, diabetes, liver diseases and stomach disorders. Regarding the Hancornia speciosa fruits, the ethnobotany indicates its use especially for treating inflammation and tuberculosis. However, no study has been done so far to prove such biological activities. The objective was evaluation anti-inflammatory activity from the fruits of Hancornia speciosa Gomes (mangabeira). Aqueous extract was prepared by decoction, subsequently submitted the liquid-liquid fractionation. The secondary metabolites were identified by high performance liquid chromatography coupled with detector diode array (HPLC-DAD) and liquid chromatography diode array detector coupled with mass spectrometry (LC-DAD-MS). The anti-inflammatory properties of the aqueous extract, dichloromethane (CH2Cl2), ethyl acetate (EtOAc) and n-butanol (n-BuOH) fractions of the fruits from H. speciosa, as well as rutin and chlorogenic acid were investigated using in vitro and in vivo models. In vivo tests comprised the xylene-induced ear edema that was measured the formation of edema, carrageenan-induced peritonitis was evaluated the total leukocytes at 4h and zymosan-induced air pouch was measured the total leukocytes and differential cell count at 6, 24 and 48 hours, whereas in vitro tests were evaluated levels of cytokines IL-1β, IL-6, IL-12 and TNF-α using ELISA obtained of carrageenan-induced peritonitis model. The results showed the presence of rutin and chlorogenic acid were detected in the aqueous extract from H. speciosa fruits by HPLC-DAD and LC-DAD-ME. Furthermore, the aqueous extracts and fractions, as well as rutin and chlorogenic acid significantly inhibited the xilol-induced ear edema and reduced cell migration in the animal models such as carrageenan-induced peritonitis and zymosan-induced air pouch. In addition, reduced levels of cytokines IL-1β, IL-6, IL-12 and TNF-α were observed. This is the first study that demonstrated the anti-inflammatory effect of aqueous extract from Hancornia speciosa fruits against different inflammatory agents in animal models, suggesting that their bioactive molecules, especially rutin and chlorogenic acid contributing, at least in part, to the anti-inflammatory effect of aqueous extract. These findings support the widespread use of Hancornia speciosa in popular medicine and demonstrate that this aqueous extract has therapeutic potential for the development of a herbal drugs with anti-inflammatory properties.

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Anxiety disorders and Parkinson’s disease (PD) affect a large portion of the world population. Indeed, therapeutic alternatives available do not contribute to improve most clinical conditions and/or are linked with undesirable side effects. Thus, there is a great demand for the development of new drugs to treatment of these diseases. Passiflora cincinnata Mast. is a native species present in several Brazilian states, popularly known as “maracujá do mato”, “maracujá tubarão” or “maracujá mochila”. Additionally, species of Passiflora genus are traditionally known for their exotic flowers, edible fruits with pronounced flavor and for their sedative, tranquilizer and anxiolytic properties reported by folk medicine. These plants possess important organic compounds such as phenols, cyanogenic glycosides, flavonoids and alkaloids, which are responsible for the anxiolytic, antioxidant, anti-inflammatory, antihyperglycemic, among others activities when tested in mammals. Despite this fact, only a few studies have been conducted to investigate the possible in vivo biological effects of Passiflora cincinnata Mast extracts. Thereby, in this study we evaluated the effects of the alcoholic extract of this plant in anxiety and PD animal model. Mice acutely or chronically administered with ethanolic extract of P. cincinnata do not showed any anxiogenic- or anxyolitic-like effect in elevated plus maze (EPM). In order to reproduce PD symptom’s in mice, we administered repeated injections of reserpine which progressively induced motor impairments such as increase in catalepsy, oral movements, and reduction of the average speed of the animals in the open field, as well as depleted dopamine prodution in SNpc cells. Furthermore, this treatment resulted in the loss of aversive memory recall in mice when undergoing PMDAT. Yet, passiflora group also show this amnesic profile. However, animals treated concomitantly with the alcoholic extract of Passiflora cincinnata Mast. showed higher latency for the onset of motor impairment evaluated by catalepsy. Thus, our results shows that the alcoholic extract of the plant P. cincinnata was able to delay the onset of the catalepsy induced by reserpine administration, plus reverted the depletion of dopamine production in SNpc cells.

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This paper proposed the study of the treatment of a synthetic wastewater contaminated with BTX by electro-oxidation batch with the anode of Ti/PbO2, and the adsorption of BTX using expanded perlite as adsorbent material, and to evaluate the best operating conditions both methods in order to perform a sequential treatment (adsorption and electro-oxidation) and achieve greater efficiency in the removal of the compounds. The operating conditions were measured: temperature, current density and applied amount of the adsorbent material, by UV-VIS analysis and Demand Chemical oxygen demand (COD). According to the experimental results, the electro-oxidative treatment was efficient in the degradation of the compounds BTX (benzene, toluene and xylenes) in synthetic sewage due to the electrochemical properties of the anode of Ti/PbO2. The applied current density and temperature promoted increased efficiency of COD removal, reaching obtain percentages greater than 70%. In the adsorption process, the temperature increase was not a factor in the removal of organic matter, while the increase in the amount of adsorbent material led to an increase in the percentage removal, obtaining 66.30% using 2 g of adsorbent. The selected operating conditions of both treatments performed separately take into account the removal efficiency of organic matter, and the low energy consumption and operating costs, so the sequential treatment were satisfactory reaching 87.26% of COD removal using adsorption as a pretreatment. Quantification of BTX through the analysis of gas chromatography at the end of the treatments also confirmed the removal efficiency of organic compounds, giving outstanding advantages to sequential treatment.

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Adsorption is a process that has become indispensable due to pollution caused by industrial activity. More economically viable adsorbents are being tested to replace the high cost of materials used. The clays can be used as adsorbents and are low cost materials, natural properties feasible for the application in the adsorption process, structural modifications are performed with ease promoting selective adsorption in these materials. The objective of this study was to synthesize and characterize adsorbents used in the adsorption of organic compounds. The adsorbents were characterized by the techniques of XRD, SEM, FTIR and TG. The results show that the studied materials have affinity to organic compounds and can be applied as adsorbents. The materials studied are viable and can be applied in the treatment of effluents contaminated in industrial scale.

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The monoaromatic compounds are toxic substances present in petroleum derivades and used broadly in the chemical and petrochemical industries. Those compounds are continuously released into the environment, contaminating the soil and water sources, leading to the possible unfeasibility of those hydrous resources due to their highly carcinogenic and mutagenic potentiality, since even in low concentrations, the BTEX may cause serious health issues. Therefore, it is extremely important to develop and search for new methodologies that assist and enable the treatment of BTEX-contaminated matrix. The bioremediation consists on the utilization of microbial groups capable of degrading hydrocarbons, promoting mineralization, or in other words, the permanent destruction of residues, eliminating the risks of future contaminations. This work investigated the biodegradation kinetics of water-soluble monoaromatic compounds (benzene, toluene and ethylbenzene), based on the evaluation of its consummation by the Pseudomonas aeruginosa bacteria, for concentrations varying from 40 to 200 mg/L. To do so, the performances of Monod kinetic model for microbial growth were evaluated and the material balance equations for a batch operation were discretized and numerically solved by the fourth order Runge-Kutta method. The kinetic parameters obtained using the method of least squares as statistical criteria were coherent when compared to those obtained from the literature. They also showed that, the microorganism has greater affinity for ethylbenzene. That way, it was possible to observe that Monod model can predict the experimental data for the individual biodegradation of the BTEX substrates and it can be applied to the optimization of the biodegradation processes of toxic compounds for different types of bioreactors and for different operational conditions.

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The monoaromatic compounds are toxic substances present in petroleum derivades and used broadly in the chemical and petrochemical industries. Those compounds are continuously released into the environment, contaminating the soil and water sources, leading to the possible unfeasibility of those hydrous resources due to their highly carcinogenic and mutagenic potentiality, since even in low concentrations, the BTEX may cause serious health issues. Therefore, it is extremely important to develop and search for new methodologies that assist and enable the treatment of BTEX-contaminated matrix. The bioremediation consists on the utilization of microbial groups capable of degrading hydrocarbons, promoting mineralization, or in other words, the permanent destruction of residues, eliminating the risks of future contaminations. This work investigated the biodegradation kinetics of water-soluble monoaromatic compounds (benzene, toluene and ethylbenzene), based on the evaluation of its consummation by the Pseudomonas aeruginosa bacteria, for concentrations varying from 40 to 200 mg/L. To do so, the performances of Monod kinetic model for microbial growth were evaluated and the material balance equations for a batch operation were discretized and numerically solved by the fourth order Runge-Kutta method. The kinetic parameters obtained using the method of least squares as statistical criteria were coherent when compared to those obtained from the literature. They also showed that, the microorganism has greater affinity for ethylbenzene. That way, it was possible to observe that Monod model can predict the experimental data for the individual biodegradation of the BTEX substrates and it can be applied to the optimization of the biodegradation processes of toxic compounds for different types of bioreactors and for different operational conditions.

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Vegetable oils are characterized as important raw materials in the supplying of natural substances of interest pharmaceutical, food and cosmetic industry. Sunflower oil stands out for its important composition present in unsaturated fatty acids such as oleic acid (C18:1) and linoleic (C18:2), responsible for many health benefits. The main objective of this study is obtain enriched fractions in unsaturated compounds from refined sunflower oil. The oil used in this study was characterized by the determination of some properties, like iodine number, acid number and viscosity. A transesterification was done to transform the triglycerides into their corresponding methyl esters of fatty acids. These was submitted the molecular distillation process, for present as an efficient alternative to separation and purification of these substances, using high vacuum and low temperatures. Of the esters fractions that was obtained, were analyzed by gas chromatography. The experimental design technique was used to evaluate the influence of the temperature variation of evaporation and condensation system on the percentage obtained residue. The evaporator temperature proved to be the most influential variable on the studied response. The optimized conditions for the answer was studied at 100 °C for evaporator temperature and 10 °C for the condenser temperature. The graph of "split ratio" showed that for the lowest flow feed (1 mL/min) and higher evaporator temperature (110 °C) was obtained in the largest fraction of distillate. It also used the study of the influence of evaporator temperature on the concentration of unsaturated compounds. The best operating conditions for temperature was 90 °C reached 82.21 % of unsaturated compounds. Elimination curves of the unsaturated compounds present in the distillate stream were obtained. The simulation results of the molecular distillation process of sunflower oil showed the concentration profiles for three different feed flow rates. The speed, temperature and thickness profiles of the liquid film were obtained. The speed of the film increases as the fluid flows through the walls of the evaporator, reaching a maximum on length of 0.075 m. The film thickness decreases on the route, since many compounds are volatilized. The result of the temperature profile had to be consistent with the literature reproduced, being constant after reaching the maximum operating temperature in the length of 0.15 m. This study allowed characterizing and focusing, through experimental analysis, unsaturated compounds and observing the sunflower oil´s behavior through process simulation.

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Vegetable oils are characterized as important raw materials in the supplying of natural substances of interest pharmaceutical, food and cosmetic industry. Sunflower oil stands out for its important composition present in unsaturated fatty acids such as oleic acid (C18:1) and linoleic (C18:2), responsible for many health benefits. The main objective of this study is obtain enriched fractions in unsaturated compounds from refined sunflower oil. The oil used in this study was characterized by the determination of some properties, like iodine number, acid number and viscosity. A transesterification was done to transform the triglycerides into their corresponding methyl esters of fatty acids. These was submitted the molecular distillation process, for present as an efficient alternative to separation and purification of these substances, using high vacuum and low temperatures. Of the esters fractions that was obtained, were analyzed by gas chromatography. The experimental design technique was used to evaluate the influence of the temperature variation of evaporation and condensation system on the percentage obtained residue. The evaporator temperature proved to be the most influential variable on the studied response. The optimized conditions for the answer was studied at 100 °C for evaporator temperature and 10 °C for the condenser temperature. The graph of "split ratio" showed that for the lowest flow feed (1 mL/min) and higher evaporator temperature (110 °C) was obtained in the largest fraction of distillate. It also used the study of the influence of evaporator temperature on the concentration of unsaturated compounds. The best operating conditions for temperature was 90 °C reached 82.21 % of unsaturated compounds. Elimination curves of the unsaturated compounds present in the distillate stream were obtained. The simulation results of the molecular distillation process of sunflower oil showed the concentration profiles for three different feed flow rates. The speed, temperature and thickness profiles of the liquid film were obtained. The speed of the film increases as the fluid flows through the walls of the evaporator, reaching a maximum on length of 0.075 m. The film thickness decreases on the route, since many compounds are volatilized. The result of the temperature profile had to be consistent with the literature reproduced, being constant after reaching the maximum operating temperature in the length of 0.15 m. This study allowed characterizing and focusing, through experimental analysis, unsaturated compounds and observing the sunflower oil´s behavior through process simulation.

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ALVES, Ana paula Melo. Vermiculitas tratadas quimicamente na obtenção de sólidos microporosos como precursores para híbridos inorgânico-orgânicos com aplicações adsortivas. 2009. 124 f. Tese (Doutorado em Quimica) - Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, PB, 2009.

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The acquisition of oligosaccharides from chitosan has been the subject of several studies in the pharmaceutical, biochemical, food and medical due to functional properties of these compounds. This study aimed to boost its production of chitooligosaccharides (COS) through the optimization of production and characterization of chitosanolytic enzymes secreted by microorganisms Paenibacillus chitinolyticus and Paenibacillus ehimensis, and evaluating the antioxidant potential of the products obtained. In the process of optimizing the production of chitosanase were employed strategies Fractional Factorial Experimental Design and Central Composite Rotatable Design. The results identified the chitosan, peptone and yeast extract as the components that influenced the production of chitosanase by these microorganisms. With the optimization of the culture media was possible to obtain an increase of approximately 8.1 times (from 0.043 to 0.35 U.mL U.mL-1) and 7.6 times (from 0.08 U.mL-1 to 0.61 U.mL-1) in the enzymatic activity of chitosanase produced by P. chitinolyticus and P. ehimensis respectively. Enzyme complexes showed high stability in temperature ranges between 30º and 55º C and pH between 5.0 and 9.0. Has seen the share of organic solvents, divalent ions and other chemical agents on the activity of these enzymes, demonstrating high stability of these crude complexes and dependence of Mn2+. The COS generated showed the ability of DPPH radical scavenging activity, reaching a maximum rate of scavenging of 61% and 39% when they were produced with enzymes of P. ehimensis and P. chitinolyticus respectively. The use of these enzymes in raw form might facilitate its use for industrial applications