• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • Tagged with
  • 12
  • 12
  • 9
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Aplica??o da parafina e do ?leo de linha?a como hidrofobizantes da vermiculita, para remo??o de derivados de ?leo diesel resentes em ?gua produzida sint?tica

Santos, Aline da Silva 29 October 2010 (has links)
Made available in DSpace on 2014-12-17T15:41:57Z (GMT). No. of bitstreams: 1 AlineSS_DISSERT.pdf: 1736350 bytes, checksum: c0d8fc169a3fee522a620adb1ae979a1 (MD5) Previous issue date: 2010-10-29 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Produced water has lately aroused interest due to their high degree of salinity, suspended oil particles, chemicals added in various manufacturing processes, heavy metals and radioactivity sometimes. Along with oil and due to its high volume production, water production is one of the pollutants of most concern in the process of oil extraction. PAHs due to their ubiquity and their characteristics carcinogenic or mutagenic and teratogenic even have attracted the attention of every scientific society. Formed from the incomplete combustion of organic matter may be natural or anthropogenic. Some materials have been researched with the goal of cleaning up environmental matrices that may be contaminated by hydrocarbons. Among these materials researched various clays have been employed, of which highlights the vermiculite. The family of phyllosilicates, vermiculite for its potential and its high hydrophobic surface area has been a tool widely used in the decontamination of water in processes of oil spills. However, when it loses its capacity expanded hydrophobic having the necessity of using a hidrofobizante to make it organophilic. Among the numerous hidrofobizantes researched and used the linseed oil was the pioneer. In this study sought to evaluate the capacity of removal of PAHs using the vermiculite hydrofobized with linseed oil and wax also, for it was made use of the 24 full factorial design as the main tool for the experiments. We also evaluated the clay grain size (-20 +48 and -48 +80 #), the percentage of hidrofobizante applied (5 and 10%) and salinity of the water produced synthesized in our laboratory (35,000 and 55,000 ppm). The molecular fluorescence spectroscopy due to its sensitivity and speed was used to verify the adsorption capacity of clay, as well as gas chromatography served as an auxiliary technique to identify and quantify the PAHs in solution. In order to characterize the vermiculite was made use of X-ray fluorescence and X-ray diffraction. The infrared and thermogravimetry were essential to note hydrophobization and the amount of coating of clay. According to the fluorescence analysis showed that the test 12 was the best result in about 98% adsorption of fluorescent compounds, however the high salinity, the smallest particle size, the highest percentage of hidrofobizante and the use of linseed oil showed greater efficiency in the removal capacity of these hydrocarbons, in accordance with the trend followed by the analysis of the major factors of the factorial design. To verify the adsorption capacity of clay using a fixed volume of water produced synthetically, used as the test base 12, at their respective levels and factors. Thus, it was observed that after adding about 1 ? liters of water solution produced synthetically, about 300 times its volume in mass, the vermiculite was able to adsorb 80% of fluorescent species present in solution / A ?gua produzida vem ultimamente despertando interesse devido ao seu elevado grau de salinidade, part?culas de ?leo em suspens?o, produtos qu?micos adicionados nos diversos processos de produ??o, metais pesados e algumas vezes radioatividade. Juntamente com o petr?leo e devido ao seu elevado volume de produ??o, a ?gua de produ??o ? um dos poluentes que mais preocupam no processo de extra??o do ?leo. Os HPAs devido a sua ubiq?idade e suas caracter?sticas carcinog?nicas/mutag?nicas e at? mesmo teratog?nicas v?m chamando a aten??o de toda sociedade cient?fica. Formados a partir da combust?o incompleta da mat?ria org?nica podem ser de origem natural ou antropog?nica. Alguns materiais v?m sendo pesquisados com o objetivo de despoluir matrizes ambientais que venham ser contaminadas por estes hidrocarbonetos. Dentre estes materiais pesquisados v?rias argilas t?m sido empregadas, das quais se destaca a vermiculita. Da fam?lia dos filossilicatos, a vermiculita por seu potencial hidrof?bico e sua elevada ?rea superficial tem sido um utens?lio bastante utilizado na descontamina??o de ?guas em processos de derramamento de ?leo. Contudo, quando expandida esta perde sua capacidade hidrof?bica havendo a necessidade do uso de um hidrofobizante para torn?-la organof?lica. Dentre os in?meros hidrofobizantes pesquisados e utilizados o ?leo de linha?a foi o pioneiro. Neste trabalho procurou-se avaliar a capacidade de remo??o de HPAs utilizando a vermiculita hidrofobizada com ?leo de linha?a e tamb?m a parafina, para isto fez-se uso do planejamento fatorial completo 24 como ferramenta principal para realiza??o dos experimentos. Avaliou-se tamb?m a granulometria da argila (-20+48 e -48+80 #), o percentual de hidrofobizante aplicado (5 e 10 %) e a salinidade da ?gua produzida sintetizada em laborat?rio (35.000 e 55.000 ppm). A espectroscopia de fluoresc?ncia molecular devido a sua sensibilidade e rapidez foi utilizada para verificar a capacidade de adsor??o da argila, bem como a cromatografia gasosa serviu como t?cnica auxiliar a fim de quantificar e identificar os HPAs presentes em solu??o. A fim de caracterizar a vermiculita fez-se uso da fluoresc?ncia de raios X e difra??o de raios X. O infravermelho e a termogravimetria foram essenciais para constatar a hidrofobiza??o e a quantidade de recobrimento do argilomineral. De acordo com as an?lises de fluoresc?ncia verificou-se que o ensaio 12 obteve o melhor resultado em torno de 98 % de adsor??o dos compostos fluorescentes, contudo a elevada salinidade, a menor granulometria, o maior percentual de hidrofobizante e o uso do ?leo de linha?a apresentaram maior efici?ncia na capacidade de remo??o destes hidrocarbonetos, de acordo com a tend?ncia seguida pela an?lise dos fatores principais do planejamento fatorial. Para verificar a capacidade de adsor??o da argila utilizando um volume fixo de ?gua produzida sint?tica, usou-se como base o ensaio 12, nos seus respectivos n?veis e fatores. Deste modo, observou-se que ap?s a adi??o de aproximadamente 1 ? litro de solu??o de ?gua produzida sint?tica, cerca de 300 vezes o seu volume em massa, a vermiculita foi capaz de adsorver 80 % das esp?cies fluorescentes presentes em solu??o
12

Otimiza??o de metodologias para determina??o de hidrocarbonetos polic?clicos arom?ticos:aplica??o em ?gua do Rio Potengi

Barbosa, Andr?a Francisca Fernandes 05 December 2008 (has links)
Made available in DSpace on 2014-12-17T15:42:05Z (GMT). No. of bitstreams: 1 AndreaFFBpdf.pdf: 4139444 bytes, checksum: afbdb6abf6434ea8e10808e3c84e0350 (MD5) Previous issue date: 2008-12-05 / Petr?leo Brasileiro SA - PETROBRAS / This work aims to detect polycyclic aromatic hydrocarbons (PAHs) through optimized analytical techniques, such as gas chromatography with flame-ionisation detector (CGFID), gas chromatography coupled to mass spectrometry (CGMS), Fluorescence Spectroscopy of Molecular and Purpot of oils and greases (POG). Apply to chemometrics, Factorial Planning 23, in the preparation of samples by liquid-liquid extraction. The sample preparation was used for liquid-liquid extraction and factors in this sample was used for the application of factorial planning 23, such as the use of ultrasound, solvents (dichloromethane, hexane and chloroform) and ratio of solvent / synthetic sample. These factors were assigned two types of levels: positive and negative. It was used to form the cube to better analyze the answers. The responses of the eight combinations were obtained in reading the spectrofluorimetric. The optimization of equipment were used, and they served in the HPA's identification of the samples collected in Rio Potengi. The optimization of the equipment was observed every 16's and PAH in the samples was found that the HPA's came from contamination of the Rio Potengi. The contamination comes through organic household waste, hospital waste, and among other contamination that comes from industries that are installed around the River The factorial design of high validity, it was observed a more effective sample preparation. The factorial design of liquid-liquid extraction showed a way to spend less solvent in less time using an ideal solvent, but also a way to extract more analyte from the matrix itself is water. In planning a smaller form factor extraction was the use of ultrasound, the ratio 1:3 corresponding to a solvent and sample 3 and the best solvent was dichloromethane who presented a viable extraction, not discarding the possibility of using also the hexane. The chloroform and may be toxic not had a good extraction / Este trabalho tem como objetivo detectar hidrocarbonetos polic?clicos arom?ticos (HPAs) atrav?s de t?cnicas anal?ticas otimizadas, tais como: Cromatografia Gasosa com Detector de Ioniza??o de Chama (CGDIC), Cromatografia Gasosa acoplada ? Espectrometria de Massa (CGEM), Espectroscopia de Fluoresc?ncia Molecular e Teor de ?leos e Graxas (TOG). Aplicar a Quimiometria, Planejamento Fatorial 23, na prepara??o de amostras por Extra??o L?quido-L?quido. A prepara??o da amostra utilizada foi ? extra??o l?quido-l?quido e nesta amostragem foi utilizado fatores para aplica??o do planejamento fatorial 23, tais como: a utiliza??o do ultrassom, solventes (diclorometano, hexano e clorof?rmio) e propor??o de solvente/amostra sint?tica. Esses fatores foram atribu?dos dois tipos de n?veis: positivo e negativo. E foi utilizada a forma de cubo para melhor analisar as respostas. As respostas das oito combina??es foram obtidas na leitura do espectrofluor?metro. A otimiza??o dos equipamentos foram utilizados, e eles serviram na identifica??o dos HPA s das amostras coletadas no Rio Potengi. Na otimiza??o do equipamento foi observado todos os 16 HPA s e nas amostras foi encontrados os HPA s que foram provenientes da contamina??o do Rio Potengi. A contamina??o por org?nicos vem atrav?s de lixos dom?sticos, lixos hospitalares, e dentre outras contamina??es que vem de ind?strias que s?o instaladas em torno do Rio. O planejamento fatorial foi de grande validade, pois foi observada uma maneira mais eficaz de prepara??o de amostra. O planejamento fatorial da extra??o liquido-liquido mostrou uma maneira de gastar menos solventes em menos tempo utilizando um solvente ideal, como tamb?m uma forma de extrair mais analito da pr?pria matriz ?gua. No planejamento fatorial a menor forma de extra??o foi a utiliza??o do ultrasom, a propor??o 1:3 que corresponde a um de solvente e 3 de amostra e o melhor solvente foi o diclorometano que apresentou uma vi?vel extra??o, n?o descartando a possibilidade de utiliza??o, tamb?m do hexano. O clorof?rmio al?m de ser t?xico n?o apresentou uma boa extra??o

Page generated in 0.0693 seconds