Xylenes
Mostrando 1-12 de 70 artigos, teses e dissertações.
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1. AN ADAPTED UNMANNED AERIAL VEHICLE FOR ENVIRONMENTAL WATER SAMPLING
In this work an unmanned aerial vehicle (UAV) was adapted to be used as an environmental tool to collect water samples of sea, estuary, and mangrove for further analysis by gas chromatography with a mass detector (GC-MS). The sampling automated system was based on a microcontroller, a solenoid valve, and a peristaltic mini-pump that was coupled to a quadcopt
Química Nova. Publicado em: 2022
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2. IMPACTOS DOS BTEX EM ÁREAS URBANAS DA CIDADE DO RIO DE JANEIRO
Most volatile organic compounds (VOC) have adverse effects on human health and the environment and react individually with different velocities and mechanisms to form ozone. The present work determined the concentration of 55 samples of benzene, toluene, ethylbenzene and xylenes (BTEX), an important subgroup of VOC, by active sampling with active carbon cart
Quím. Nova. Publicado em: 20/07/2020
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3. Simultaneous Determination of Environmental Contaminants with Different Volatilities in Tap Water Samples Using a New Approach to Single-Drop Microextraction Procedure
A new single-drop microextraction approach is proposed for the extraction of compounds with a wide range of volatilities from tap water samples with separation/detection by gas chromatographymass spectrometry. This new microextraction mode is called direct immersion-headspace-single drop microextraction (DI-HS-SDME). Trihalomethanes (THMs), hydrocarbons w
J. Braz. Chem. Soc.. Publicado em: 2015-08
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4. Determinação de compostos monoaromáticos voláteis provenientes de emissões de veículos leves, em estacionamentos subterrâneos. / Determination of volatile monoaromatic compounds emissions from light vehicles in underground parking lots.
This study aims to determine the contribution of evaporative emissions from light passenger vehicles to the degradation of the air quality. The main objective is to evaluate the concentrations volatile monoaromatic compounds benzene, toluene, ethylbenzene and xylenes (BTEX) indoors, in a site that represents the reality of the vehicular fleet of the Metropol
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/02/2012
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5. Impacto ambiental de kartódromos situados na cidade do Rio de Janeiro: monitoramento de BTEX no ar e do nível de ruído
In this work, noise and aromatic hydrocarbons levels of indoor and outdoor karting circuits located in Rio de Janeiro were assessed. The sampling was perfomed using active charcoal cartridges, followed by solvent desorption and analysis by gas chromatography with mass spectrometry detection. This study demonstrated that the karting circuits, venues for enter
Quím. Nova. Publicado em: 2012
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6. RemoÃÃo de BTEX em SoluÃÃo Aquosa por AdsorÃÃo usando ZeÃlita SintÃtica Modificada. / Removal of BTEX in aqueous solution by adsorption using synthetic zeolite modified.
BTEX (benzene, toluene, ethylbenzene and xylenes) are organic compounds of particular concern due to their toxicity. BTEX occur in the environment as products of incomplete oxidation of fossil fuels, thus polluting the atmosphere. Also, the disposal of industrial effluents, oil spills, and fuels leaks at gas stations are sources of BTEX contamination in soil
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/04/2011
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7. Poluição e a densidade de vegetação: BTEX em algumas áreas públicas de Curitiba - PR, Brasil
The occurrence of benzene, toluene, ethylbenzene, and xylenes (BTEX) in some public areas of Curitiba-PR, Brazil, was evaluated. Their concentrations were then related to the vegetation's density in each area. Average benzene concentrations varied from 3.9 to 6.1 μg m-3, with higher values occurring in poorly dense vegetation areas. For toluene, average con
Química Nova. Publicado em: 2010
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8. Estudo de compostos orgânicos voláteis na atmosfera da região metropolitana de Campinas / Study of volatile organic compounds in the atmosphere of metropolitan area of Campinas
This work presents a study of volatile organic compounds (VOC) found in the atmosphere of Metropolitan Area of Campinas (Campinas, SP). The first step was to perform a vehicular emissions inventory of the study area. Vehicular emissions were estimated using emission factors from new vehicles and bottom-up approach, considering different categories of vehicle
Publicado em: 2010
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9. Optical sensors and instrumentations for determination of contaminants in water / Sensores opticos e instrumentação para determinação de contaminantes em aguas
This work describes the development of optical sensors for determination of benzene, toluene, ethylbenzene and xylenes (BTEX) and metal ions in water. For the determination of BTEX, monoliths of polydimethylsiloxane (PDMS) were inserted into a bottle filled with aqueous solutions of BTEX compounds for a pre-defined period of time. Afterwards the sensing phas
Publicado em: 2009
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10. Determinação de benzeno, tolueno, etilbenzeno e xilenos em gasolina comercializada nos postos do estado do Piauí
Automotive gasoline consists of a complex mixture of flammable and volatile hydrocarbons derived from crude oil with carbon numbers within the range of 4-12 and boiling points range of 30-225 ºC. Its composition varies with the kind of crude oil and the type of refinery process that they undergone. Aromatics hydrocarbons, in particular benzene, toluene, eth
Química Nova. Publicado em: 2009
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11. DegradaÃÃo anaerÃbica de BTEX em reatores alimentados com Ãgua contaminada por gasolina
The underground water quality has been damaged because of storage tank spills from gas stations. The most common organic pollutants are the BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) as a consequence of their toxicity, carcinogenicity and teratogenicity. The use of anaerobic bioreactors is an alternative for the bioremediation of water cont
Publicado em: 2008
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12. Avaliação e critérios de eficiência nos processos de tratamento de fluido de corte por eletroflotação / Evaluation criteri and efficiency in the procedures for treatment of fluid cutting by eletroflotation
In the machining process cutting fluids are used to facilitate the manufacture of metal parts, which has resulted in problems of various orders, ranging from the generation of harmful effects on the desktop to the aggression of the environment with their improper disposal. The cutting fluids are composed of oils and minerals, synthetic solutions and water, c
Publicado em: 2008