Дисертації: "Liquid/liquid extraction purification"

1

Pinheiro, Regiane Silva. "Study of liquid-liquid extraction for methyl biodiesel purification process." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14103.

Повний текст джерела

Анотація:

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
In the process of purification of biodiesel is of extreme importance washing methyl or ethyl ester rich- phase, since in conventional processes there is a great amount of water. During the washing is extracted primarily excess alcohol. Composition data for the washing process of biodiesel is still scarce in the literature and the study of liquid-liquid equilibrium provides the means to develop equipment and to optimize the extraction processes. Thus the main goal of this work is to determine equilibrium data for three different ternary systems: water - methanol - soybean biodiesel; corn biodiesel â methanol â water; methanol - coconut biodiesel - water at 20 Â C and 40 Â C. The experiments were carried out in equilibrium cells where the temperature was kept constant by thermostat control. The experimental determination was made by the method of densimetry. The consistency of data obtained for the tie lines was verified by correlations. It was verified by the ternary graphs, little influence of temperature on the systems studied. The equilibrium data were correlated liquid-liquid models for the activity coefficient NRTL, UNIQUAC and UNIFAC and proved quite satisfactory.
No processo de purificaÃÃo do biodiesel, a lavagem da fase rica em metil ou etil Ãster Ã de extrema importÃncia, visto que nos processos convencionais hÃ um grande gasto de Ãgua. Durante a lavagem Ã extraÃdo principalmente Ãlcool em excesso. Dados de composiÃÃes para a lavagem de biodiesel ainda sÃo escassos na literatura e o estudo do equilÃbrio lÃquido-lÃquido pode fornecer meios para o desenvolvimento de equipamentos e otimizaÃÃo dos processos de extraÃÃo. Dessa forma, o principal objetivo dessa dissertaÃÃo foi determinar dados de equilÃbrio lÃquido- lÃquido para os sistemas ternÃrios contendo biodiesel de soja + metanol + Ãgua, biodiesel de milho + metanol e Ãgua e biodiesel de coco + metanol + Ãgua, a 20 ÂC e 40 ÂC. Os experimentos foram feitos em cÃlulas de equilÃbrio mantendo a temperatura constante. A determinaÃÃo experimental das misturas ternÃrias foi feita pelos mÃtodos de titulaÃÃo e densimetria. A consistÃncia dos dados das linhas de amarraÃÃo foi verificada pelas correlaÃÃes de Othmer-Tobias e Hand. Verificou-se por meio de grÃficos ternÃrios, pouca influÃncia da temperatura sobre os sistemas estudados. Os dados de equilÃbrio lÃquido-lÃquido foram correlacionados pelos modelos para coeficiente de atividade NRTL, UNIQUAC e UNIFAC e mostraram-se bastante satisfatÃrios.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Campos, Assunção Mariana. "Etude physicochimique et formulation d'un nouveau solvant d'extraction pour la purification de l'acide phosphorique." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066045/document.

Повний текст джерела

Анотація:

Cette thèse avait pour objectif de développer de nouveaux systèmes d’extraction liquide-liquide compatibles avec le procédé Prayon pour la purification de l’acide phosphorique produit par voie humide. Une étude bibliographique complète des solvants d’extraction étudiés dans la littérature pour l’extraction liquide-liquide de l’acide phosphorique nous a permis d’identifier des candidats potentiellement intéressants. Une étude approfondie des propriétés d’extraction de ces systèmes et de leur sélectivité vis-à-vis des espèces métalliques nous a finalement permis de nous focaliser par la suite sur trois solvants d’extraction : le dibutyl éther (DBE), le diisobutyl carbinol (DiBC) dilué dans le diisopropyl éther (DiPE) et la Fentamine T0810 (ATS) dilué dans le DiPE. La formulation de ces mélanges a ensuite été optimisée en veillant à étudier le comportement de ces systèmes à chaque étape du procédé d’extraction liquide-liquide, c’est à dire l’extraction, la désextraction et le lavage. Cette étude a également permis de fixer les conditions opératoires optimales, notamment le rapport des volumes des phases. Au cours de cette étude, des phénomènes complexes de transitions de phases réversibles de la phase organique de monophasique vers biphasique (formation de troisième phase) et biphasique vers monophasique (retour à une phase organique unique) ont été mis en évidences expérimentalement. Pour finir, un modèle physicochimique d’extraction fondé sur des bilans de masse a été développé. Ce modèle s’avère très utile pour décrire l’extraction de l’acide phosphorique et de l’eau et la variation des volumes des phases au cours de l’extraction
This PhD thesis was focused on the development of new extraction systems to purify phosphoric acid from wet phosphoric acid (WPA). The new system should be respectful of the current Prayon’s process flowsheet designed for the use of the mixture tri-n-butyl phosphate(TBP) and diisopropyl ether (DiPE) as extraction solvent. Firstly, extractants exhibiting different structures and functional groups were screened in order to assess their efficiency and selectivity towards phosphoric acid. Three new promising extraction systems were identified: diisobutyl ether (DBE), diisocarbinol (DiBC) in DiPE, and Fentamine T0810 (ATS) in DiPE. Secondly, our effort was directed to the comprehension of the physico-chemical phenomena involved in the extraction of phosphoric acid by the mixture TBP/DiPE at first, and enriched to describe the other systems studied later. Finally, a simulation model describing the solvent extraction of phosphoric acid by the solvent currently employed by Prayon is presented. This model accounts for the significant volume variation during the extraction of phosphoric acid and allows performing optimizations of extraction parameters even at very high phosphoric acid concentrations (6-14M)

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Hewitson, Peter. "Intermittent counter-current extraction : a new continuous dynamic liquid-liquid extraction methodology." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/13900.

Повний текст джерела

Анотація:

For the pharmaceutical industry, the manufacture of high value pharmaceuticals from natural products, chemical synthetic routes or fermentation processes all require intensive downstream processing steps to produce a pure final product. A small footprint liquid-liquid processing method would help to reduce the capital cost and process development time of this downstream processing. In this thesis, it is hypothesised that continuous liquid-liquid extraction can be achieved using a standard hydrodynamic counter-current chromatography (CCC) instrument by switching the flow of the liquid phases between normal phase and reversed phase intermittently, so separating a feed stream into two eluant flows. A model of the process was derived and tested on three scales of instrument, from the semipreparative to the pilot scale. The method developed, Intermittent Counter-current Extraction (ICcE) was compared to dual-flow counter-current chromatography (DFCCC), the classical method of applying continuous extraction using a counter-current chromatograph. ICcE was found to be advantaged due to the more stable phase volume ratio achievable in the columns and the ability to operate the procedure on standard commercial twin-column CCC instruments which operate at high g-field. The robustness of the ICcE method was successfully demonstrated across a range of phase system polarities and at high throughput (1kg/day on a preparative instrument) with model mixtures of pharmaceutical compounds. The effectiveness of this new processing method was confirmed on three industrially relevant case studies. Firstly a polar extract from natural senna pods to extract important sennosides, secondly an intermediate polarity highly complex active pharmaceutical ingredient waste stream to recover the main active component and thirdly a non-polar natural product extract to recover macrocarpal compounds. In summary, the ICcE method now offers another tool in the range of liquid-liquid separation methods available to the pharmaceutical and other high value industries.

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Lane, Marshalle. "Dispersive liquid-liquid micro-extraction coupled with gas chromatography for the detection of trihalomethanes in different water sources in the Western Cape, South Africa." Thesis, Cape Peninsula University of Technology, 2018. http://hdl.handle.net/20.500.11838/2852.

Повний текст джерела

Анотація:

Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2018.
Trihalomethanes (THMs) are a group of four compounds that are formed, along with other disinfected by-products. This happens when chloride or other disinfectants are used to control microbial contamination in drinking water, which then reacts with natural organic or inorganic substances in water. Trihalomethanes are better known by their common names such as chloroform, bromodichloromethane, chlorodibromomethane and bromoform. These four compounds are known to be classified as cancer group B carcinogens (shown to cause cancer in laboratory animals). Trihalomethane levels tend to increase with pH, temperature, time and the level of “precursors" present. Precursors are known to be organic substances which react with chloride to form THMs. One significant way of reducing the amount of THMs in water is to eliminate or reduce chlorination before filtrations and reduce precursors. There are guideline limits for THMs in the SANS 241:2015 document, but they are not continuously monitored and their levels in natural water are not known. The aim of this study is to develop a rapid, fast and reliable liquid-liquid microextraction technique, to determine the presence of THMs in natural water sources. This study particularly focuses on different water sources e.g. river, underground, borehole and chlorinated water. Chlorinated water is the water that has been presumably treated for bacteria and fungus growth. The results that were obtained for chlorinated water are as follow, 10.120 μg/L − 11.654 μg/L for chloroform, 2.214 μg/L - 2.666 μg/L for bromodichloromethane, 0.819 μg/L − 0.895 μg/L chlorodibromomethane and 0.103 μg/L - 0.135 μg/L for bromoform from validation data. All these THMs concentrations have been found to be below the SANS 241:2015 limits. Natural water shows a very high affinity for chloroform. This is what is expected under normal conditions as chloroform is the most abundant THM of all THMs present in natural water. The liquid-liquid microextraction technique that was optimized and used for the determination of THMs in this study is a rapid, simple and inexpensive technique that provides low limits of detection (LOD) e.g. 0.1999 μg/L chlorodibromomethane and 0.2056 μg/L bromoform and wide dynamic range (LOQ) of 0.6664 μg/L chlorodibromomethane and 0.6854 μg/L bromoform for the determination of THMs.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Mouhib, Mohamed. "Equilibres entre phases liquides et solides dans les systèmes H₂O-H₃PO₄-Solvant (DIPE ; TBP ; MIBK ; Hexane) en vue de la purification de l’acide phosphorique : Étude expérimentale et modélisation thermodynamique." Electronic Thesis or Diss., Lyon 1, 2024. http://www.theses.fr/2024LYO10276.

Повний текст джерела

Анотація:

L'acide phosphorique (H3PO4) est le deuxième acide inorganique le plus produit au monde, principalement utilisé dans la fabrication d'engrais. Cependant, son utilisation dans des applications technologiques de pointe, telles que l'industrie des semi-conducteurs, nécessite une pureté extrêmement élevée qui ne peut être obtenue qu’après élimination poussée des cations métalliques et matière organique dissous, dont l’origine est la roche phosphatée initiale. Pour optimiser la purification de l'acide phosphorique élaboré par voie humide (WPA), il est primordial de maîtriser les équilibres entre phases mis en jeu dans deux méthodes complémentaires et efficaces : l'extraction liquide-liquide et la cristallisation. Dans ce cadre, le présent travail est focalisé sur l’étude systématique et la modélisation des équilibres entre phases liquide-liquide, solide-liquide, liquide-liquide-solide impliquant l’acide phosphorique, l’eau et divers solvants organiques. La 1ère partie présente une analyse systématique des équilibres liquide-liquide des systèmes quaternaires (H2O-H3PO4-DIPE-TBP, H2O-H3PO4-DIPE-MIBK, et H2O-H3PO4-TBP-MIBK) pour évaluer l’effet synergique de ces solvants mixtes sur l'efficacité d’extraction de l'acide phosphorique. En outre, dans le système ternaire H2O-H3PO4-DIPE, l'efficacité est également évaluée en tenant compte de l'influence de l’addition des solvants TBP et MIBK sur la formation d’une troisième phase liquide. La deuxième partie se concentre sur l’étude des équilibres solide-liquide dans le système H2O-P2O5, incluant l'étude des systèmes binaires H2O-H3PO4 et H3PO4-H4P2O7 par des mesures de solubilité, calorimétrie et diffraction des rayons X. Cette étude permet de délimiter les domaines de stabilité de l’acide phosphorique et de ses hydrates, et de mettre en évidence l’existence de nouvelles phases stables, métastables, ainsi que d'éventuels polymorphismes. Ensuite, une modélisation par le modèle quasi-idéal permet d’affiner les données expérimentales et d'obtenir des informations sur la structure des solutions. Enfin, la troisième partie explore les équilibres liquide-liquide-solide (LLSE) du système H₂O- H3PO4-C6H14 en fonction de la température. Les données expérimentales sont modélisées dans le domaine de température entre 283.2 K et la température de fusion de l’acide phosphorique anhydre, offrant une représentation précise des équilibres de démixtion et des SLE dans tout le domaine de composition
Phosphoric acid (H3PO4) is the second most widely produced inorganic acid in the world, mainly used in fertilizer manufacturing. However, its use in advanced technological applications, such as the semiconductor industry, requires extremely high purity, which can only be achieved after extensive removal of dissolved metal cations and organic matter, from the original phosphate rock. To optimize the purification of wet-process phosphoric acid (WPA), it is essential to master the phase equilibria involved in two complementary and effective methods: liquid-liquid extraction and crystallization. In this context, the present work focuses on the systematic study and modeling of liquid-liquid, solid-liquid, and solid-liquid-liquid phase equilibria involving phosphoric acid, water, and various organic solvents. First part presents a systematic liquid-liquid equilibrium analysis of quaternary systems (H2O-H3PO4-DIPE-TBP, H2O-H3PO4-DIPE-MIBK, and H2O-H3PO4-TBP-MIBK) to assess the synergistic effect of these mixed solvents on phosphoric acid extraction efficiency. In addition, in the ternary H2O-H3PO4-DIPE system, the efficiency was also evaluated taking into account the influence of the addition of TBP and MIBK solvents on the formation of a third liquid phase. The second part focuses on the study of solid-liquid equilibria in the H2O-P2O5 system, including the study of the binary systems H2O-H3PO4 and H3PO4-H4P2O7 by solubility measurements, calorimetry and X-ray diffraction. This study delimits the stability domains of phosphoric acid and its hydrates, and highlights the existence of new stable, metastable phases, as well as possible polymorphisms. Then, the Quasi-ideal model was used to refine the experimental data and obtain information on the structure of the solutions. Finally, the third part explores the solid-liquid-liquid equilibria (SLLE) of the H2O-H3PO4-C6H14 system as a function of temperature. Experimental data was modeled from 283.2 K to the melting temperature of anhydrous phosphoric acid, providing an accurate representation of demixing equilibria and SLLE throughout the composition range

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Alenazi, Mohrah. "Extraction and Purification of Biologically Active Metabolites from Rhodococcus sp. MTM3W5.2." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etd/3507.

Повний текст джерела

Анотація:

Rhodococcushas been recognized as a potential antibiotic producer. Recently, a strain of Rhodococcussp. MTM3W5.2 was isolated from a soil sample collected in Morristown, Tennessee and was found to produce an inhibitory compound which is active against other related species. The purpose of this research is to extract, purify and analyze the active metabolite. The compound was extracted from RM broth cultures and purified by preliminary fractionation of crude extract through a Sephadex LH-20 column. Further purification was completed using semi-preparative reversed phase column chromatography. Final purification was obtained using multiple rounds of an analytical C18 HPLC column. Based on the results achieved in the UV-Vis spectroscopy and high-resolution mass spectroscopy, the two desired compounds at a retention time of at 57 and 72 min could be polyketides with the molecular formulas C52H78O13 and C19H32O1N1/C13H34O1N1, respectively.

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Gomes, Joana Margarida Mota. "Purification of IgY using aqueous biphasic systems composed of good’s buffers ionic liquids." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15391.

Повний текст джерела

Анотація:

Mestrado em Bioquímica - Métodos Biomoleculares
The increased inefficiency of antibiotics observed in the past few years, derived from the growing number of drug-resistant organisms and the appearance of individuals with impaired immune system, led to a significant research on antibodies for use in passive immunotherapy. Antibodies obtained from the egg yolk of immunized hens, immunoglobulin Y (IgY), are a promising alternative to mammalian antibodies. They can be obtained in higher titres and by less invasive techniques, thus opening the door for a new kind of more economic biopharmaceuticals. However, the available techniques for the IgY extraction and purification are time-consuming, labor intensive, low yielding, provide low-purification levels, are of high cost and cannot easily be scaled-up for industrial applications. In this work, ABS composed of C6H5K3O7 and ILs synthetized by the combination of anions with buffer capacity (Good’s buffers), with the tetrabutylphosphonium ([P4444]+) and tetrabutylammonium ([N4444]+) cations, were investigated. The use of different ILs allowed the study of the cation and anion nature on the phase diagrams behaviour and thus on their ability to form ABS. Further, the ability of these systems as an alternative purification platform for IgY, by a selective extraction, was studied. The complete extraction and purification of IgY was not achieved in a single with the investigated ABS. However, the study of the proteins profile of the coexisting phases allowed to conclude that all proteins migrate for the top phase during the partitioning process, and that a complex between the ILs and the different proteins present in the water-soluble fraction of proteins from egg yolk was formed. Still, the results obtained reveal that the system composed of 20.1 wt % [N4444][CHES] + 16.9 wt % C6H5K3O7 is the most promising ABS for the IgY extraction.
Recentemente, a utilização de anticorpos para imunoterapia passiva tornou-se uma área de investigação atrativa. Tal facto deve-se à diminuição da eficiência dos antibióticos pelo aumento do número de organismos resistentes. Os anticorpos obtidos a partir da gema do ovo de galinhas imunizadas, imunoglobulinas Y (IgY), são uma alternativa viável e promissora aos anticorpos de mamíferos. Estes apresentam inúmeras vantagens, dado que podem ser obtidos em maior quantidade e serem recolhidos por técnicas menos invasivas. Apesar das vantagens apresentadas, as técnicas disponíveis para a extração e purificação de IgY são demoradas, trabalhosas, apresentam baixo rendimento, levam a baixos fatores de pureza, apresentam custos elevados e não são facilmente aplicáveis a nível industrial. Assim, o principal objetivo deste trabalho consistiu no desenvolvimento de uma plataforma de purificação alternativa para a extração e purificação de IgY, utilizando sistemas aquosos bifásicos (SAB) constituídos por líquidos iónicos com capacidade tampão. Neste trabalho foram estudados SAB constituídos por C6H5K3O7 e líquidos iónicos, sendo os últimos sintetizados pela combinação de aniões com capacidade tampão (Good’s buffers), com os catiões tetrabutilamónio ([N4444]+) e tetrabutilfosfónio ([P4444]+). Os líquidos iónicos utilizados permitiram o estudo da influência do anião e do catião nos diagramas de fase, ou seja sob a capacidade dos diferentes líquidos iónicos para formar SAB. De seguida, foi testada a capacidade destes sistemas como uma plataforma alternativa para a extração seletiva, e posterior purificação, de IgY. A purificação de IgY não foi conseguida num único passo de extração com os sistemas estudados. No entanto, o estudo do perfil proteico de ambas as fases dos sistemas permitiu concluir que, durante a partição, todas as proteínas migraram para a fase superior e que houve formação de um complexo entre o IL e algumas das proteínas constituintes da fração aquosa proteica da gema do ovo. Os resultados obtidos revelaram que, entre os vários SAB estudados, o mais promissor para a extração de IgY, é aquele constituído por 20.1 (m/m) % [N4444][CHES] + 16.9 (m/m) % C6H5K3O7.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Gilbert, Christopher Donald. "Non-Newtonian conversion of emulsion liquid membranes in the extraction of lead and zinc from simulated wastewater." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/10911.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Elias, Moacyr Jorge. "Determinação das condições de atividade otima, da estabilidade termica e da cinetica da hidrolise enzimatica de bromelina presente na casca e no talo do abacaxi (Ananas comosus L. Merril) variedade perola." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267036.

Повний текст джерела

Анотація:

Orientador: Elias Basile Tambourgi
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-15T00:12:34Z (GMT). No. of bitstreams: 1 Elias_MoacyrJorge_D.pdf: 3281919 bytes, checksum: a06d734eab8439e1da9e683c7b3eb667 (MD5) Previous issue date: 2010
Resumo: A bromelina, enzima presente no abacaxi, hidrolisa ligações peptídicas das proteínas; tem aplicação em diversas áreas envolvendo alimentos, medicina e nutrição animal. No abacaxi a bromelina está presente no talo, na polpa e na casca do fruto. Visando avaliar a bromelina presente no fruto brasileiro Ananás comosus L. Merril, variedade pérola, enfocando seu aproveitamento quando recuperada a partir dos resíduos da industrialização, foram pesquisadas, em comparação com a bromelina pura, condições de pH e temperatura para maior atividade, estabilidade térmica ao longo do tempo em várias temperaturas e a cinética da sua atividade catalítica, empregando caseína como substrato. O extrato foi obtido pela trituração da casca e do talo interno do fruto e a reação de hidrólise, com pH controlado, efetuada em reator com 75 mL de volume útil sob constante agitação. Após a reação foi retirada amostra, adicionada em tubo contendo ácido tricloroacético e centrifugado, analisando a absorbância do sobrenadante. Atividade e a cinética foram expressas em mmol tirosina / L.minuto pela absorbância a 280 nm dos aminoácidos aromáticos gerados na hidrólise da caseína. Foram empregadas três relações enzima / substrato (em massa): 1 / 25, 1 / 50 e 1 / 125 para os ensaios relativos ao planejamento experimental em estrela tendo como ponto central pH em 7,0 e temperatura de 35 °C, os resultados foram tratados fornecendo as equações do modelo e as superfícies de resposta; as equações foram tratadas matematicamente fornecendo gráficos da melhor atividade em função da temperatura; os resultados do planejamento experimental mostraram similaridade entre a bromelina dos resíduos do fruto e a bromelina pura tomada como padrão. Para a estabilidade térmica os ensaios foram efetuados determinando a atividade para a relação 1 / 25 sob temperaturas variando entre 25 °C e 62 °C ao longo de 180 minutos com duas faixas de pH: a de melhor atividade definida no planejamento experimental (5,5 a 6,5) e entre 3,3 e 3,5; os resultados foram tratados analisando o gráfico da atividade em função do tempo mostrando que o modelo de ordem um é adequado para descrever a inativação térmica da enzima e que ela ocorre de maneira mais acentuada na faixa de pH 3,3 a 3,5 com valor do fator de freqüência k0 (minuto-1) 2,5 x1032 vezes maior para o extrato. Os ensaios para determinar a cinética da atividade catalítica da bromelina sobre a caseína foram efetuados a temperatura constante de 35 °C e pH de máxima atividade definido no planejamento experimental para cada uma das três relações enzima / substrato estudadas; foram elaboradas as curvas da concentração de aminoácidos formados ao longo do tempo (zero a 15 minutos) e os resultados tratados calculando a derivada das curvas no tempo zero (velocidade inicial); o modelo de Michaelis - Menten mostrou ser adequado para descrever o mecanismo de hidrólise da caseína pela bromelina e os resultados indicam que os valores da velocidade máxima (Vmax) e da constante de Michaelis (Km) são maiores para o extrato dos resíduos do fruto do que para a bromelina pura.
Abstract: The bromelain, enzyme found in pineapple, hydrolyses peptide protein bonds; there is application in several areas involving food, medicine and animal nutrition. In pineapple the bromelain is present in the flesh, skin and core of the fruit. Aiming to evaluate the bromelain present in Brazilian fruit Ananas comosus L. Merril, pérola type, focusing its use from industrialization residues recovering, it was searched, comparing with pure bromelain, pH conditions and temperature for higher activity, thermal stability along the time under several temperatures and the kinetics of its catalytic activity, using casein as a substrate. The extract was obtained crushing the skin and core of the fruit and the hydrolysis reaction, with controlled pH, done in a 75 mL net volume reactor under constant stirring. After reaction a sample was taken, added to a tube with tri chloroacetic acid and centrifuged, analyzing the supernatant absorbance. Activity and kinetics were expressed as mmol of tyrosine / L.min from absorbance at 280 nm of aromatic amino acids generated by casein hydrolysis. Three enzyme / substrate ratio were employed (weight basis):1 / 25, 1 / 50 and 1 / 125 for star type experimental design assays with central point at 7.0 for pH and at 35 °C for temperature, the results were processed giving the model equation and surface responses, the equations were mathematically treated giving graphics of best activity as a function of temperature; the experimental design results showed similarity between bromelain from fruit residues and pure bromelain taken as reference. The assays for thermal stability were carried out by activity determination for 1 / 25 ratio under temperatures varying from 25 °C and 62 °C during 180 minutes for two pH ranges: that for best activity defined from experimental design (5.5 to 6.5) and between 3.3 to 3.5; the results were treated by the analysis of the graphics of activity as a function of time showing that the order one model is adequate to describe the enzyme thermal inactivation and that it is stronger at pH range of 3.3 to 3.5 with values of frequency factor k0 (minute-1) 2.5 x1032 times bigger for the extract.The assays to determine the kinetics of bromelain catalytic activity on casein were carried out at constant temperature of 35 °C and pH of maximum activity defined by experimental design for each one of the three studied enzyme / substrate ratio; curves were built for the concentration of formed amino acids along the time (from zero to 15 minutes) and the results treated calculating the curves derivative at time zero (initial rate); the Michaelis - Menten model showed to be adequate to describe the casein hydrolysis mechanism of casein by bromelain and the results indicate that the maximum reaction rate (Vmax) values and the Michaelis constant (Km) values are bigger for the fruit residues extract than that for pure bromelain.
Doutorado
Sistemas de Processos Quimicos e Informatica
Doutor em Engenharia Química

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Barros, Kleber Vanio Gomes. "Caracterização e purificação da enzima bromelina derivada do curaua (Ananas erectifolius) em sistema bifasico aquoso PEG/fosfato." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267111.

Повний текст джерела

Анотація:

Orientador: Elias Basile Tambourgi
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-15T00:05:27Z (GMT). No. of bitstreams: 1 Barros_KleberVanioGomes_M.pdf: 726082 bytes, checksum: f7ee21d9c4e2a18b7c38d3e3a1baccd2 (MD5) Previous issue date: 2009
Resumo: O curauá (Ananas erectifolius) é uma planta fibrosa proveniente da Amazônia brasileira, pertencente à família Bromeliaceae e ao gênero Ananas. A bromelina é uma protease de origem vegetal, obtida de diversas espécies da família Bromeliaceae. A bromelina tem utilização bastante difundida em processos industriais nas áreas alimentícia e farmacêutica. Efeitos antiinflamatórios da enzima, como também, o seu uso no tratamento da angina, na indigestão entre outros, estão documentados na literatura científica. Estudos de métodos para purificação de biomoléculas que viabilizem a sua obtenção em larga escala com custo reduzido são importantes áreas de pesquisa na biotecnologia. A extração líquido-líquido através de sistemas bifásicos aquosos (SBA) pode ser usada como técnica de pré-purificação de bioprodutos. Estes sistemas formam duas fases aquosas imiscíveis ou parcialmente miscíveis entre si. Podem ser formados a partir da mistura de dois polímeros ou de um polímero e um sal, a exemplo do sistema PEG (polietilenoglicol)/fosfato de potássio. Foi estudada a enzima bromelina derivada das folhas de ambas as variedades: curauá branco e curauá roxo. Pesquisou-se também a recuperação da enzima por extração líquido-líquido em sistemas de duas fases aquosas PEG/fosfato. Realizou-se ensaios em batelada para a extração e recuperação da enzima, utilizando como indicador o coeficiente de partição. Obteve-se fatores de purificação da enzima bromelina para o sistema fosfato de potássio e polietileno glicol 4000 e 6000, nos pH de 7,0; 8,0 e 9,0 a 25 °C. Estudou-se a partição em três diferentes "tie-lines". Analisou-se a influência do pH e do comprimento das linhas de amarração no coeficiente de partição da enzima. Na purificação da bromelina derivada das folhas do curauá branco, observou-se os melhores resultados no sistema bifásico aquoso PEG 4000/Fosfato em pH 7,0. Observou-se que o sistema PEG 6000/Fosfato em pH 7,0 apresentou os melhores resultados em relação à purificação da enzima bromelina derivada das folhas do curauá roxo.
Abstract: The curauá (Ananas erectifolius) is a fibrous plant from brazilian Amazon, belonging to the Bromeliaceae family and Ananas genus. Bromelain is a protease from vegetable origin, obtained from several species of this family. The bromelain has widespread use in industries process, such as in food and pharmaceutical areas. Antiinflammatory effects enzyme and also it uses in angina treatment, indigestion among others are documented in scientific literature. Methods' studies to purification of biomolecules that allow their achievement in large scale with low cost are important research's areas in biotechnology. The liquid-liquid extraction through aqueous twophase system (ATPS) can be used as technical of pre-purification of bioproduct. These systems form aqueous two-phase immiscible or partially miscible within themselves. They can be obtained by the addition of two polymers or one polymer and a salt, such as the PEG - poly(ethyleneglycol) - and potassium phosphate salt system. In the present report we characterized the bromelain enzyme that comes from the leaves of white curauá and purple curauá, and also investigated the recuperation of the enzyme by liquid-liquid extraction in aqueous two-phases PEG-phosphate systems (ATPS). The assays to extraction and recovery of the enzyme were carried out in batch mode, using the partition coefficient as indicator. Getting to factors purification of the enzyme bromelin to PEG 4000 and 6000 and potassium phosphate salt in ATPS, at pH 7.0, 8.0 and 9.0 at 25 ºC. We studied the partition through three different tie-lines. The influences of pH and tie-line length in partition coefficient of enzyme were analyzed. In the purification of bromelain derived from the leaves of white curauá, we observed the best results in PEG 4000/phosphate ATPS at pH 7.0. Furthermore, the system PEG 6000/phosphate at pH 7.0 showed the best results in relation to the purification of the enzyme bromelain derived from the leaves of purple curauá.
Mestrado
Sistemas de Processos Quimicos e Informatica
Mestre em Engenharia Química

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Pereira, Matheus Mendonça. "Ionic-liquid-based aqueous biphasic systems as concentration and purification platforms of cancer biomarkers." Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21532.

Повний текст джерела

Анотація:

Doutoramento em Engenharia Química
Cancer is worldwide a major cause of death, with ca. 14 million new diagnosed cases each year. Therefore, the search for more efficient early-stage diagnosis methods is crucial aiming at increasing the treatment rate and survival of patients, as well as to decrease the expenses associated to advanced treatment. Prostate specific antigen (PSA) and lactate dehydrogenase (LDH) are proteins commonly found in human fluids (urine and serum), and have been considered as cancer biomarkers and in the monitoring of cancer treatment. However, due to their low concentration and the complexity of biological matrices with a large amount of other metabolites present (proteins, DNA, RNA), the pretreatment of samples for their concentration and purification is usually applied. In this work, alternative pretreatment techniques based on aqueous biphasic systems (ABS) composed of ionic liquids (ILs) have been studied to extract, concentrate and purify proteins that can be used as cancer biomarkers, such as PSA and LDH. To this end, several preliminary works were performed to identify the most promising phase-forming components and conditions to create ABS that could be used for the extraction of proteins. These works comprise studies on the extraction of amino acids and model proteins in ABS, followed by investigations on their use with more complex matrices. Finally, ABS were investigated for the extraction and concentration of tumor biomarkers, namely PSA and LDH. In summary, the versatility of ILs allows the tailoring of the ABS extraction and concentration capacity, selectivity, and/or induced precipitation of cancer biomarkers from human fluids. The systems here developed are a viable and efficient alternative for the pretreatment of biological samples (serum and urine), thus contributing to the development of early-stage methods of cancer diagnosis.
O cancro é mundialmente uma das principais causas de morte, com cerca de 14 milhões de novos casos diagnosticados por ano. Neste sentido, o desenvolvimento de métodos de diagnóstico mais eficientes em estágio inicial da doença é crucial para auxiliar o tratamento e aumentar a taxa de sobrevida dos pacientes, além de diminuir as despesas associadas aos tratamentos avançados. O antígeno específico da próstata (PSA) e a lactato desidrogenase (LDH) são proteínas comumente encontradas nos fluidos humanos (urina e soro) e têm sido alvo de atenção como biomarcadores do cancro e na monitorização do seu tratamento. No entanto, devido à sua baixa concentração e à complexidade das matrizes biológicas com uma grande quantidade de outros metabólitos presentes (proteínas, DNA, RNA), é geralmente aplicado um ou mais passos de pré-tratamento de amostras. Neste trabalho, foram estudadas técnicas alternativas de pré-tratamento baseadas em sistemas aquosos bifásicos (SAB) constituídos por líquidos iónicos (LIs) para extrair, concentrar e purificar proteínas que podem ser usadas como biomarcadores de cancro, como a PSA e LDH. Para este fim, foram realizados vários trabalhos preliminares para identificar os componentes e condições de formação mais promissores para criar SAB que possam ser utilizados para a extração de proteínas. Estes trabalhos contemplam a utilização de SAB para a extração de aminoácidos e proteínas modelo, assim como a utilização de SAB em matrizes mais complexas. Finalmente, os SAB foram aplicados para a extração e concentração de biomarcadores tumorais, nomeadamente PSA e LDH. Em suma, com este trabalho verificou-se que a versatilidade dos LIs permite adaptar a capacidade de extração e concentração, seletividade, e/ou precipitação induzida de biomarcadores de cancro a partir de fluidos humanos. Os sistemas aqui desenvolvidos são uma alternativa viável e eficiente para o pré-tratamento de amostras biológicas (soro e urina), contribuindo assim para o desenvolvimento de métodos de diagnóstico de cancro precoces.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Manikindi, Pushpavathi Reddyvari. "Extraction, Purification and Characterization of an Antibiotic-like Compound Produced by Rhodococcus sp. MTM3W5.2." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etd/3116.

Повний текст джерела

Анотація:

The bacterium Rhodococcus is a potential source for novel antimicrobial metabolites. Recently, the Rhodococcus strain MTM3W5.2 was isolated from a soil sample collected from Morristown, East Tennessee and was found to produce an inhibitor molecule that is active against similar Rhodococcus species. The aim of this research is to extract, purify, and characterize the active compound. The compound was obtained from both agar and broth cultures of strain MTM3W5.2 and purified by primary fractionation of crude extract on a Sephadex LH-20 column, followed by semi-preparative reversed phase column chromatography. Final purification was achieved using multiple rounds of an analytical C18 HPLC column. Based on the results obtained from UV-Vis, FT-IR, and HR-MS, the molecule is a polyketide with a molecular formula of C52H78O13 and an exact mass of 911.5490 amu. The partial structure of this compound has been determined using 1D and 2D NMR spectroscopy.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Sbruzzi, Dalva. "Análise da viabilidade econômica da purificação da bromelina das folhas de curauá em sistema bifásico aquoso PEG/Fosfato." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266969.

Повний текст джерела

Анотація:

Orientador: Elias Basile Tambourgi
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
Made available in DSpace on 2018-08-16T08:45:10Z (GMT). No. of bitstreams: 1 Sbruzzi_Dalva_M.pdf: 1983604 bytes, checksum: 3ca47c66cbfb0f6dcff7d83c5b614ccc (MD5) Previous issue date: 2010
Resumo: O curauá (Ananas Erectifolius L.B. Smith), espécie vegetal de porte herbáceo, é uma monocotiledônea pertencente à família Bromeliaceae, nativa da região norte do Brasil, especialmente da Amazônia, de onde pode ser extraída a bromelina. Essa faz parte de um grupo de enzimas proteolíticas, usadas na indústria alimentícia e como medicamento, pois oferece amplo espectro de eficácias terapêuticas: antiedemas, anti-inflamatórias, antitrombóticas e atividades fibrinolíticas. O desenvolvimento de novos processos de extração e purificação de proteínas é muito importante, uma vez que essa é uma etapa limitante na produção de bioprodutos. Sistemas de duas fases aquosas são amplamente utilizados para a separação e purificação de biomoléculas. As vantagens da extração em duas fases aquosas, em comparação com outros métodos de purificação, são o elevado rendimento, a faixa de trabalho próxima do equilíbrio, a fácil ampliação de escala e o uso em processos contínuos. Esta pesquisa propõe a caracterização da bromelina do curauá e a sua purificação por extração líquido-líquido em duas fases aquosas, formadas por um polímero (polietilenoglicol) e um sal (fosfato de potássio). Apresenta também um estudo sobre os custos do processo e o preço de venda estimado, e demonstra a sua viabilidade econômica, quer seja para uso como pré-processo nos tradicionais sistemas cromatográficos, quer para a comercialização direta, como alternativa para a bromelina do abacaxi. Os resultados da caracterização mostraram que as condições ideais de trabalho são pH 8,5 e temperatura 35º C para a variedade branca, e pH 8,5 e 30º C de temperatura para a variedade roxa. A massa molar é de 24 kDa, e o melhor sistema de partição da bromelina foi o SBA PEG 4000 em pH 9. A solução enzimática dos melhores sistemas contém 7 U de bromelina e, aproximadamente, 17 mg/L de proteína total medida por Bradford (curauá branco); e 6 U de bromelina e, aproximadamente, 23 mg/L de proteína total medida por Bradford (curauá roxo). O preço de venda calculado para um litro dessa solução enzimática, quando não se obtém lucro (margem de lucro desejada é 0%), foi estimado em R$75,06. Assim, pode-se concluir que o processo de purificação da bromelina das folhas de curauá, ao ser utilizado sistema bifásico aquoso, PEG/sal, é promissor no que diz respeito a sua possibilidade de produção em escala industrial
Abstract: Curaua (Ananas erectifolius L.B. Smith) is a mocotyledonous herbaceous specie belonging to the Bromeliaceae family and it is native to the north region of Brazil, especially the Amazonian Complex, that we can extract bromelain which belongs to a group of proteolytic enzymes derived from herbaceous species of Bromeliaceae family, which are used in food industries and as drugs as such as they offer a wide spectrum of therapeutic efficacies: antiedemateous, antiinflammatory, antithrombotic and fibrinolytic activities. The development of new extraction and purification processes of proteins is very important, as this is a limiting step in the production of bioproducts. Aqueous two-phase systems are widely used for separation and purification of biomolecules. The advantages of aqueous two-phase extraction compared to other purification methods lie in high productivity, working range close to equilibrium, easy scale up and use in continuous processes. This research proposes the curaua's bromelain characterization, and its purification by a liquid-liquid extraction in aqueous two-phase system, formed by a polymer (polyethylene glycol) and a salt (potassium phosphate). It also presents a study about the costs of this process and the estimated sale price, showing its economic viability, whether it is for use as a pre-process in traditional chromatographic systems or direct commercialization, as an alternative for the bromelain of pineapple. The curaua's bromelain characterization results showed that the ideal working conditions are pH 8.5 and 35 ºC of temperature to white variety and pH 8.5 and 30°C of temperature to purple variety. The curaua's molecular weight is 24 kDa and the best bromelain partitioning system was the SBA PEG 4000 at pH 9. The enzyme solution of the best purification system contains 7 U of bromelain and about 17 mg/L of total protein measured by Bradford (white curaua) and 6 U of bromelain and about 23 mg/L of total protein measured by Bradford (purple curaua). The estimated sale price for a liter of this enzyme solution, when profit is not achieved (0% of desired markup), was estimated at R$ 75, 06. So, the curaua's bromelain purification process using an aqueous two-phase system, PEG/salt, is promising with regard to the possibility of industrial scale production
Mestrado
Sistemas de Processos Quimicos e Informatica
Mestre em Engenharia Química

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Duran, Renan Ravetti. "Procédés d’extraction et de purification de molécules à haute valeur ajoutée issues de la biomasse bois." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0325.

Повний текст джерела

Анотація:

Les sous-produits qui proviennent de l’industrie du bois, particulièrement les nœuds, contiennent différents types de molécules qui peuvent être valorisées comme source de composants bioactifs pouvant répondre à des besoins thérapeutiques. C’est sur cette idée que le projet "Le Bois Santé" a été conçu. Grâce à la collaboration de plusieurs partenaires, le présent travail vise dans un premier temps à développer des procédés d’extraction "verts" (solide-liquide et supercritique) pour obtenir un extrait riche en lignanes à partir d’un mélange de nœuds d’épicéa commun et de sapin pectiné. Les effets des conditions opératoires sur le rendement d’extraction de chaque composé cible et sur l’activité anti-oxydante des extraits ont été déterminés. Afin d’étudier le procédé complet, le projet vise à étudier l’impact des procédés de concentration et de séchage de l’extrait à partir de l’évaporation sous vide et de la lyophilisation. De plus, la séparation et la purification des composés ont été développées et optimisées par simulation grâce à la technique de chromatographie frontale
By-products from wood industry, particularly knots, contain different types of molecules that can be valued as a source of bioactive components meeting therapeutic needs. It is on this idea that the project "Le Bois Santé" was designed. Through the collaboration of several partnerships, the present work aims initially to develop a "green" extraction processes (solid-liquid and supercritical) to obtain an extract rich in lignans from a mixture of norway spruce and silver fir knots. The effects of operating conditions on the extraction yield of each target compound and the antioxidant activity of the extracts were determined. To understand the entire process, the project aims to investigate the impact of concentration and drying processes using vacuum evaporation and lyophilisation. Moreover, the separation and purification of the compounds have been developed and optimized using frontal chromatography technique

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Mekaoui, Nazim. "Contribution à l'étude de la chromatographie à contre-courant : partage de composés ionisables, nouvelles colonnes et purification séquentielles." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10249/document.

Повний текст джерела

Анотація:

La chromatographie à contre courant (CCC) est une technique de purification chimique préparative quitravaille avec un système biphasique liquide. Une phase est la phase mobile, l'autre phase est la phasestationnaire. Il n'y a aucun support solide: un champ de force centrifuge est utilisé pour maintenir en place laphase stationnaire. Ce travail est une contribution à l'étude de la purification préparative par CCC. Après uneimportante étude bibliographique des procédés de purification en continu tant en CCC qu'autres, il est montréque la méthode dite "multi-dual-mode", ou MDM, est une solution possible. Elle consiste à utiliser le fait queles deux phases liquides peuvent servir de phase stationnaire: il suffit d'inverser le sens de circulation et lanature de la phase mobile (méthode dual-mode). Le mélange est séparé de façon classique pendant untemps chronométré, puis on inverse le rôle des phases: la phase mobile devient stationnaire et vice versa eton inverse également le sens de circulation (ascendant devient descendant ou vice versa). On sort lescomposants du mélange soit d'un coté de la colonne CCC, soit de l'autre. La méthode est mise en oeuvrepour purifier le Bleu de Coomassie en le débarassant des ses composés polaires (d'un coté) et apolaire (del'autre coté de la colonne et en accumulant dans la colonne la fraction de polarité intermédiaire, fractiond'intérêt. Une nouvelle colonne hydrostatique de petit volume (30 mL) a également été testée: elle permetde tester un nouveau système liquide très rapidement
Counter-current chromatography (CCC) is a preparative purification technique that works with the twoliquid phases of a biphasic liquid system. One phase is used as the mobile phase when the other phase isused as the stationary phase. There is no solid support: centrifugal fields are used to obtain a support-freeliquid stationary phase. This work contains an exhaustive bibliographic study of what can be found in theliterature concerning continuous chromatographic processes. The multi-dual-mode (MDM) process was foundto be the best one able to purify large amount of crude mixtures. The MDM method starts with a classicalseparation of the mixture followed by a switch of both the liquid phase nature and the flowing direction. Themobile phase flowing e.g. in a descending direction becomes the stationary phase. The previous stationaryphase becomes the mobile phase flowing in the ascending direction (or vice versa). The purified compoundsof the introduced mixture are eluted at one side of the column or the other according to their polarity. TheMDM method was used to purify a crude sample of Coomassie Blue: the polar part of the dye was eluted atthe column top (or head) and the apolar part at the column bottom (or tail) while the essential part of the dyewas trapped inside the CCC column. The work also presents a new small volume (30 mL) hydrostatic CCCcolumn. It is shown that this column could be used to test quickly the potential of a given biphasic liquidsystem

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Ferreira, Juliana Ferrari. "Caracterização e purificação da enzima bromelina em sistema de duas fases aquosas PEG/Fosfato." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266254.

Повний текст джерела

Анотація:

Orientador: Elias Basile Tambourgi
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-10T17:39:24Z (GMT). No. of bitstreams: 1 Ferreira_JulianaFerrari_M.pdf: 1163600 bytes, checksum: 2fad54014afb77b7e2ead964968cb026 (MD5) Previous issue date: 2007
Resumo: A bromelina é uma protease de origem vegetal, obtida de diversas espécies da família Bromeliaceae, que está presente no talo e no fruto do abacaxi. O uso da bromelina é baseado em sua atividade proteolítica nas indústrias alimentícias e principalmente na farmacêutica brasileira. A bromelina é muito bem documentada pelos seus efeitos curativos em todas as condições inflamatórias, além de ter sua eficácia provada na cura de vários outros problemas de saúde, tais como: angina, indigestão e problemas respiratórios. Vários métodos de purificação da bromelina estão em estudo, sobretudo da bromelina do talo. A extração líquido-líquido é aplicada há muitos anos como uma valiosa técnica laboratorial de separação. Esta pode ser usada como um passo da pré-purificação usando um sistema de duas fases aquosas. Esses sistemas foram testados com sucesso, são sistemas formados por duas fases aquosas imiscíveis ou parcialmente miscíveis entre si, obtidas pela mistura de polímeros hidrofílicos ou um desses polímeros e um sal, como o sistema PEG (polietileno glicol) e o fosfato de potássio. O presente trabalho estudou a caracterização da enzima e a recuperação da bromelina presente na casca e talo do abacaxi, por extração líquido-líquido em sistemas de duas fases aquosas PEG/ fosfato. Realizou-se ensaios em batelada para a extração e recuperação da enzima, utilizando como indicador o coeficiente de partição. Obtiveram-se diagramas de fases para o sistema fosfato de potássio e polietileno glicol 1500 e 4000 nos pH¿s de 6 a 11, a 25 °C. Estudou-se três diferentes ¿tie-lines¿. Analisou-se a influência do pH e do comprimento das ¿tie-lines¿ no coeficiente de partição da enzima
Abstract: The bromelains are proteases from vegetable origin, obtained from several species of Bromeliaceae family, which are found in pineapple¿s stem and fruit. The bromelains uses are based on its proteolytic activity on food industries and mostly at Brazilian pharmaceutical industry. The bromelains has been documented by its therapeutic effects at all inflammatory conditions, in addition to its attested efficiency of cure of various health problems, such as angina, indigestion and respiratory problems. Various bromelains¿ purification methods has been studied, particularly of stem¿s bromelain. Aqueous two-phase systems has been applied for several years as a good laboratorial separation technique and they can be used as a prepurification step. These systems have been tested with large success. The systems are formed by two aqueous phases immiscible or partially miscible within themselves, obtained by the addition of hydrophilic polymers or one hydrophilic polymer and a salt, such as the poly(ethylene glycol) ¿ PEG ¿ and potassium phosphate salt systems. This work studied the enzyme characterization and recuperation presented in the pineapple¿s stem and skin, by aqueous two-phase systems liquid-liquid extraction. Batch assays were performed aiming the enzyme extraction and recuperation, using the partition coefficient as indicator. The phase diagrams from PEG and potassium phosphate salts aqueous two-phase systems were obtained for PEG molecular weight of 1500 and 4000 at pH 6.0 to 11.0, at 25 ºC. Three different tie-lines were also studied. The pH and tieline length influence on the enzyme partition coefficient were analysed.
Mestrado
Sistemas de Processos Quimicos e Informatica
Mestre em Engenharia Química

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Diemer, Étienne. "Intensification du procédé d’extraction, de purification et de fonctionnalisation des acides caféoylquiniques à partir de coproduits de la culture de l’endive." Electronic Thesis or Diss., Compiègne, 2024. http://www.theses.fr/2024COMP2821.

Повний текст джерела

Анотація:

La racine forcée d’endive est un coproduit de la culture de l’endive, produit caractéristique du Nord de la France, de la Belgique et des Pays-Bas. Actuellement sous utilisé en méthanisation ou en alimentation animale, ce coproduit contient pourtant des molécules d’intérêts à haute valeur ajoutée : les acides caféoylquiniques. Ces molécules possèdent des activités antioxydantes, anti-inflammatoires et permettent de limiter les maladies du désordre métabolique. Ce travail de thèse vise à intensifier le prétraitement, l’extraction, la purification et la fonctionnalisation des acides caféoylquiniques à partir des racines forcées pour développer de nouvelles molécules bioactives biosourcées potentiellement intéressantes pour le secteur cosmétique et nutraceutique. Une dernière partie de la thèse porte sur l’étude technico-économique du procédé pour estimer sa rentabilité économique en fonction du secteur d’application visé. La première partie porte sur l’effet des prétraitements conventionnels (découpe et séchage) ainsi que l’effet d’un prétraitement électrique par champs électriques pulsés sur les teneurs en acides caféoylquiniques dans la biomasse. L’effet de l’ajout d’une solution antioxydante lors de l’extraction est également étudié. Dans un deuxième temps, une optimisation de l’extraction est réalisée à partir de biomasse sèche et fraiche. L’influence de facteurs tels que la température, le ratio solide/liquide, ainsi que la nature du solvant a été étudiée. De plus, des cinétiques d’extraction ont été tracées pour étudier les paramètres cinétiques à l’aide d’un modèle empirique. La pureté de l’extrait obtenu étant faible, des étapes de purification sont donc nécessaires. Par la suite, les travaux se sont portés sur la purification de l’extrait brut à l’aide de résines macroporeuses ainsi que par extraction liquide/liquide. Pour la purification par résine, un screening de résines est réalisé suivi d’une optimisation des conditions opératoires de purification avec la résine choisie. Des modélisations des phénomènes d’adsorption sont réalisées pour déterminer les étapes limitantes ainsi que la capacité maximale d’adsorption. Pour l’extraction liquide/liquide, un screening de solvants verts est effectué à partir d’un milieu aqueux et hydro-éthanolique puis une optimisation des conditions opératoires avec le meilleur solvant est réalisée. La pénultième partie de la thèse cherche à fonctionnaliser par estérification les acides caféoylquiniques à partir d’une solution modèle puis d’un extrait réel. Les conditions d’estérification sont optimisées pour augmenter la vitesse de réaction ainsi que le taux de conversion. Des esters avec différentes longueurs de chaine sont obtenus et l’activité antioxydante ainsi que les propriétés anti-UV sont étudiées. La fonctionnalisation est par la suite effectuée sur un extrait réel. Une étude technico-économique conclut la thèse permettant d’ouvrir sur des perspectives quant aux conditions nécessaires à l’industrialisation du procédé de valorisation des racines forcées d’endive
Forced chicory root is a by-product of Belgian endive culture, a typical crop of northern France, Belgium and the Netherlands. Currently under-utilized in methanation or animal feed, this by-product contains molecules of interest: caffeoylquinic acids. These molecules have antioxidant and anti-inflammatory properties, and a potential for reducing metabolic disorders. This thesis aims to intensify the pre-treatment, extraction, purification and functionalization of caffeoylquinic acids from forced chicory roots to develop new bioactive biosourced molecules of potential interest to the cosmetics and nutraceutical sectors. The final part of the thesis deals with a technico-economical study of the process to estimate its economic profitability in relation to the targeted application sector. The first part focuses on the effect of conventional pretreatments (cutting and drying) and the effect of pulsed electric field pretreatment on caffeoylquinic acid content in biomass. The effect of adding an antioxidant solution during extraction is also investigated. Secondly, extraction optimization is carried out using dry or fresh biomass. The influence of factors such as temperature, solid/liquid ratio and solvent type were studied. In addition, extraction kinetics were performed to study kinetic parameters using empirical models. As the purity of the extract obtained is low, purification steps are needed. The thesis then focused on purifying the crude extract obtained using macroporous resins and liquid/liquid extraction. For resin purification, resin screening was carried out, followed by optimization of the purification operating conditions with the chosen resin. Models of adsorption phenomena are carried out to identify the limiting stages and the maximum adsorption capacity. For liquid/liquid extraction, green solvent screening is carried out on aqueous and hydro-ethanolic media, followed by optimization of operating conditions with the best solvent. The penultimate part of the thesis seeks to functionalize caffeoylquinic acids by esterification, starting with a model solution and then a real extract. Esterification conditions are optimized to increase both reaction speed and conversion rate. Esters with different chain lengths were obtained, and biological activities such as antioxidant activity and anti-UV properties were studied. Functionalization is also performed with real extract. A technico-economic study concludes the thesis, opening up prospects for the industrialization of the forced chicory roots valorization process

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Solastiouk, Pierre. "Application de l'extraction liquide-liquide au traitement et a la revalorisation d'effluents industriels." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13140.

Повний текст джерела

Анотація:

Proposition d'une nouvelle approche de l'elimination des effluents des ateliers de traitement de surface. Separation zinc/nickel en solution concentree et separation du chrome hexavalent dans des effluents chromates

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Haddou, Boumediene. "Purification d'effluents par extraction à deux phases aqueuses." Toulouse, INPT, 2003. http://www.theses.fr/2003INPT009G.

Повний текст джерела

Анотація:

La plupart des composés hydrophobes présents dans une solution aqueuse, peuvent être solubilisés dans les micelles d'un tensioactif non ionique, puis concentrés dans le petit volume du coacervat, après séparation des phases. Dans ce travail, afin d'étudier l'extraction du phénol ou de l'alcool benzylique (soluté) de leurs solutions aqueuses (pollution soluble), nous avons choisi de travailler avec des alcools plyéthoxylés aisément et rapidement biodégradables. Les résultats expérimentaux d'extraction du phénol ou d'alcool benzylique en solution aqueuse à 0. 15% massique, sont exprimés par les quatre grandeurs suivantes : pourcentage de phénol soluté, concentrations résiduelles en soluté et en tensio-actif dans la phase diluée, fraction volumique de coacervat à l'équilibre. Le procédé dérivé de l'extraction à deux phases aqueuses, consiste en l'élimination d'une pollution dispersée par désémulsification. Le cas des boues polluées par des huiles de coupe utilisées dans le sciage, le taillage et le pollissage du granit en fournit un excellent exemple.

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Sukhbaatar, Tamir. "Approche multi-échelle pour la compréhension de mécanismes d'extraction de l'uranium en utilisant des liquides ioniques." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2018. http://www.theses.fr/2018ENCM0002.

Повний текст джерела

Анотація:

En raison de leurs propriétés intéressantes telles que faible tension de vapeur, non-inflammabilité et grande fenêtre électrochimique, les Liquides Ioniques sont considérés comme alternatifs aux solvants organiques volatils et font l’objet d’études dans diverses applications comme par exemple en extraction liquide-liquide qui est l’une des techniques de séparation la plus utilisée en hydrométallurgie. L’influence de ces nouveaux diluants sur les propriétés d’agrégation des molécules extractantes et sur leurs propriétés extractantes n’a jusqu’à aujourd’hui pas été appréhendée de façon générale, et encore moins, quant à l’extraction de l’uranium d’un lixiviat acide. Les travaux de cette thèse se focalisent donc sur l’étude de l’effet de l’agrégation des extractants usuels (mélange synergique HDEHP/TOPO et trioctylamine respectivement) et des nouveaux composés bifonctionnels issus des familles amidophosphonates et oxyde d’aminophosphines sur l’extraction de l’uranium i) des milieux phosphates et ii) des milieux sulfates. Les propriétés extractantes ont pour la première fois été comparées à leurs propriétés d’agrégation dans un liquide ionique sélectionné, par des mesures de diffusion des rayons X et des neutrons aux petits angles. Ces données en complément des mesures de tension de surface ont permis de déterminer pour chaque système, la Concentration d’Agrégation Critique, analogue de la Concentration de Micellisation Critique pour les tensioactifs, qui est reliée à l’énergie libre de micellisation. Les mécanismes d’extraction ainsi que la nature des espèces extraites ont également été recherchés afin de comparer les résultats du milieu liquide ionique à ceux du milieu classique
Due to their attractive properties such as negligible vapor pressure, non-flammability and large electrochemical window, Ionic Liquids are considered to be good substitutes to volatile organic compounds and have been main topic of many research studies for different applications including solvent extraction, which is one of the widely used techniques in hydrometallurgy. Despite a large number of reported mechanistic studies, effect of such diluents on both of extracting agents’ capacity and self-assembling feature has not been elucidated so far and even less concerning uranium extraction from a leachate produced by ore leaching. In this context, main focus of the present thesis has been uranium extraction from i) phosphate media and ii) sulfate media by using ionic liquid as a diluent of an extracting phase. First of all, a screening test of different ionic liquids has been performed with the reference extracting agents (HDEHP/TOPO mixture for extraction from phosphate media and trioctylamine from sulfate media) as well as with amidophosphonate and aminophosphine oxide bifunctional compounds. Then, uranium extraction mechanisms in a selected ionic liquid with these extractants have been investigated at molecular and supramolecular scales. As an analogy to the Critical Micellar Concentration which is related to the Gibbs free energy of Micellization in a case of surfactants, a Critical Aggregation Concentration has been determined by using results obtained by Small-Angle X ray, Neutron Scattering techniques and interfacial tension measurements. Finally, the results obtained in the ionic liquid have been compared to those obtained in a conventional molecular diluent

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Esteves, Pedro Duarte de Oliveira. "Extraction and purification of theobromine using ionic liquids." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/16056.

Повний текст джерела

Анотація:

Mestrado em Bioquímica - Bioquímica Clínica
Theobromine is an alkaloid present in cocoa and it is used in the treatment of atherosclerosis, hypertension, angina, among others. Due to its importance, the aim of this work consists on the development of an efficient and sustainable technology for the extraction of theobromine from cocoa beans. For the development of a purification technique for theobromine extracted from cocoa, aqueous biphasic systems (ABS) composed of ionic liquids (ILs) were initially studied to infer on the most promising systems. Cholinium-based ILs, based on a non-toxic and biocompatible cation, were used combined with two polymers (PPG 400 and PEG 400) and an inorganic salt (K3PO4). The respective phase diagrams at 298 K and atmospheric pressure were determined, as well as their extraction efficiencies for theobromine. The results obtained indicate that K3PO4 has a greater ability to induce the formation of ABS compared to PEG 400 and PPG 400. ABS consisting of K3PO4 also have a high potential for the extraction of theobromine, with extraction efficiencies ranging between 96.4 and 99.9 %. Based on the most promising ILs for the purification step, they were further used in aqueous solution to extract theobromine from cocoa beans, with extraction yields ranging between 4.5% and 6.5 wt%. Finally, ABS were applied to the aqueous solutions containing theobromine from the cocoa extract, with extraction efficiencies ranging between 96.7 and 99.0%.
A teobromina é um alcaloide utilizado no tratamento de aterosclerose, hipertensão, angina, entre outros. Dada a sua importância medicinal, o principal objetivo deste trabalho consistiu no desenvolvimento de uma técnica eficiente e sustentável para extrair teobromina das sementes de cacau. Visando o desenvolvimento de uma técnica de purificação para o extrato obtido a partir do cacau, primeiramente estudaram-se sistemas aquosos bifásicos (SABs) constituídos por líquidos iónicos (LIs) para inferir sobre os sistemas mais promissores. Foram utilizados LIs à base do catião colínio, catião não tóxico e biocompatível, em conjunto com 2 polímeros (PPG 400 e PEG 400) e um sal inorgânico (K3PO4) para a formação de SABs. Determinaram-se os diagramas de fase, à temperatura de 298 K e à pressão atmosférica, assim como as eficiências de extração destes sistemas para a teobromina. Os resultados obtidos indicam que o K3PO4 apresenta uma maior capacidade de induzir a formação de SABs do que o PPG 400 e o PEG 400. Os SABs constituídos por K3PO4 também demonstraram ter um grande potencial para a extração da teobromina, com eficiências de extração entre 96,4 e 99,9 %. Tendo por base os LIs mais promissores para a etapa de purificação, estes foram posteriormente utilizados em solução aquosa para a extração de teobromina a partir das sementes de cacau, tendo sido obtidos valores de extração de teobromina entre 4,5 e 6,5 (m/m) %. Por fim, procedeu-se à utilização de SABs como método de purificação a partir da solução aquosa contendo o extrato, e obtiveram-se valores de eficiências de extração entre 96,7 e 99,0 %.

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Lee, Jonathan George Malcolm. "Liquid-liquid extraction in centrifugal fields." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336273.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Haj, Youssef Mouna. "Extraction liquide - liquide et extraction par émulsions appliquées à la purification de l'acide phosphorique vis-à-vis du cadmium." Châtenay-Malabry, Ecole centrale de Paris, 2008. http://www.theses.fr/2008ECAP1108.

Повний текст джерела

Анотація:

Dans cette thèse nous nous intéressons à la purification de l'acide phophorique par extraction du cadmium. Deux techniques ont été utilisées : l'Extraction liquide liquide et l'Extraction par membrane liquide émulsionnée. Notre apport par rapport à la première technique consiste en l'utilisation d'un nouveau couple extractant-desextractant qui sont respectivement l'acide di (2) éthylheryl dithiophosphorique synthétisé au sein du laboratioire et le (HCl 4M ou HCl 1M+NaCl 3M). Les essais expérimentaux réalisés ont permis de montrer l'efficacité de ce nouveau couple extractant-desextractant et de déduire les mécanisme d'extraction et de désextraction. L'étude de l'Extraction par membrane liquide émulsionnée nous a permis de démontrer expérimentalement que cette technique permet d'extraire la même quantité de cadmium tout en utilisant moins de D2EHDTPA. En optimisant la formulation de l'émulsion, nous avons montré qu'on peut atteindre un facteur de concentration élevé. Ceci signifie qu'on peut concentrer le cadmium dans un volume très réduit de la phase aqueuse de l'émulsion, ce qui est intéressant de point de vue de protection de l'environnement. L'étude de ces deux techniques d'extraction est accompagnée par l'étude des tests de faisabilité de procédés industriels. Le procédé retenu est sous forme d'un étage en mélangeur décanteur. Le pilote proposé en extraction liquide-liquide comporte deux étages d'extraction dont la performance de chacun est de 99% et 6 étages en désextraction. Avec un tel montage on a pu concentrer le cadmium 50 fois et ceci en partant d'une concentration initiale de cadmium égale à 40 mg. L-1.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Hindocha, Ravinder K. "Liquid-liquid extraction with long wavelength fluorescence detection." Thesis, Loughborough University, 1994. https://dspace.lboro.ac.uk/2134/31792.

Повний текст джерела

Анотація:

Long wavelength fluorophores, methylene blue, Rhodamine 800, 3,3'diethyloxacarbocyanine iodide (DODC) and 1, 1',3,3,3' ,3' -hexamethylindotricarbocyanine perchlorate (HIDTCP) were investigated as probes to quantify drugs after liquid-liquid extraction. Fluorescence measurements in the long wavelength region (550-1000nm) are a recent development in photoluminescence spectroscopy and offer many advantages compared with conventional measurements which are made in the ultraviolet and visible spectral regions. These include, reduced background fluorescence in the presence of biological materials; reduced scattering; decreased photodecomposition and the availability of inexpensive, solid state optical components which operate in the long wavelength spectral region. On-line liquid-liquid extraction was carried out using a phase separator, with an efficiency of separation of 96%, designed "in-house". This technique offers the advantages of low sample consumption; rapid rates of analysis and minimisation of operator contact with the extracting solvent when compared with manual extraction. The proposed extraction manifold used was able to determine flufenamic acid, phenylbutazone and warfarin within their therapeutic ranges. Studies also revealed that the process was buffer pH and ion dependent. Ion pairs as well as differing ratios of fluorophore, depending upon the fluorophore, were found to be extracted in the presence of named drugs. The technique was found to be suitable for the detection of the drugs when present in human serum within their therapeutic ranges. Finally, an investigation into an alternative to chloroform (density = 1.47g/ml) as the extracting solvent using dimethylmaleonate (density = 1.154g/ml) and diethylacetoacetate (density = 1.025g/ml) proved unsuccessful.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Brodkorb, M. "Multicomponent and contamination effects in liquid-liquid extraction." Thesis, University of Bradford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504892.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Jildeh, Hanin [Verfasser]. "Liquid-Liquid Extraction Columns: Parameter Estimation / Hanin Jildeh." München : Verlag Dr. Hut, 2015. http://d-nb.info/107976903X/34.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Solanki, A. S. "Homogeneous liquid-liquid extraction using consolute point systems." Thesis, University of Bradford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384269.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Atalla, Abdo Mena. "Study of the liquid-liquid extraction of gallium." Thesis, University of Hertfordshire, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315652.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Schuur, Boelo. "Enantioselective liquid-liquid extraction in centrifugal contactor separators." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2008. http://irs.ub.rug.nl/ppn/.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Santangelo, Francesca [Verfasser]. "Ionic Liquids as extraction solvents for Biobutanol purification / Francesca Santangelo." München : Verlag Dr. Hut, 2013. http://d-nb.info/1045989274/34.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Holbach, Marcus Alexander [Verfasser]. "Enantioselective Liquid-Liquid Extraction in Process Intensified Extraction Columns / Marcus Alexander Holbach." München : Verlag Dr. Hut, 2015. http://d-nb.info/1079768823/34.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Otu, Emmanuel Ogbonna. "Liquid-liquid extraction studies of the rare earth elements." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5804.

Повний текст джерела

Анотація:

This thesis is directed towards the study of the solvent extraction behaviour of the lanthanides and aluminium, bismuth, calcium and zinc whose radii and/or charges are similar to those of the REE. A brief review of the fundamentals and classification of extraction systems and of extractants is presented in Chapter 1. Chapters 2 and 3 are reviews of the properties and uses of the lanthanides and solvent extraction using phosphonate and sulphonate extractants, respectively. Chapter 4 deals with experimental procedures, results, discussions and conclusions. The extraction of zinc (II), calcium (II), aluminium (III), bismuth (III) and some lanthanide ions from aqueous perchlorate solutions into hexane solutions of 2-ethylhexyl phenylphosphonic acid, HEH$\Phi$P, was studied. The mechanisms of extraction are discussed on the basis of the results obtained by slope analysis. Depending upon the size and charge of the ion, the extracted species contain varying numbers of extractant molecules and phosphonate groups as ligands. Monomeric complexes are formed in the presence of excess extractant. High loadings of the extractant phase with the metal ion resulted in suppression of the extraction. Alkali ions were not extracted but alkali perchlorate suppressed the extraction through the effect of ionic strength on the metal ion activity. To further investigate the mechanism of extraction, $\sp{31}$P NMR of the organic phase following extraction of lanthanum was studied. A polymeric lanthanum-HEH$\Phi$P complex which precipitates out in the organic phase is formed at high (saturation) loading of this phase. A structure is proposed for this complex. The thermodynamics of extraction of these ions from perchlorate solutions into petroleum ether solutions of dinonylnaphthalene sulphonic acid, DNNSA, and HEH$\Phi$P were studied. In the case of DNNSA, extraction of the trivalent ions is dominated by the enthalpy of complexing. Electrostriction of large complex micelles by the complexed ion is postulated in order to account for the entropy effect. For the divalent ions, the enthalpy of dehydration of the ion is more important. A strategy for improving the separation factors is proposed. In the case of HEH$\Phi$P, charge density of the cation has a major influence upon the mechanism of the reaction and in turn upon the thermodynamic parameters. The ionic strength of the aqueous phase influences the thermodynamic parameters in the HEH$\Phi$P and DNNSA systems. Amongst the REE, lanthanum shows a singular behaviour. The extractions have been compared with those that employ dinonylnaphthalene sulphonic acid and factors that are responsible for the greater selectivity of the phosphonate have been elucidated. Development of an extraction chromatographic separation procedure for the lanthanides with a view to separating them from other matrix elements and fractionating them among themselves was studied. This was to be achieved by employing an organic polar solvent in the later stages of column elution. However, low recoveries were observed upon ashing the organic eluent and DCP determinations. The presence of phosphate (as KH$\sb2$PO$\sb4$ or H$\sb3$PO$\sb4)$ was found to lead to depression of analyte signal (concentration) in the DCP.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Barker, Michael H. "Electrochemistry at liquid/liquid interfaces for metal ion extraction." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367192.

Повний текст джерела

Анотація:

The aim of this project was to produce a selective extraction system for the separation of precious metal ions from waste electrolyte streams utilising liquid/liquid electrochemical techniques. During the course of this project the work partitioned into three different aspects of charge transfer: electron transfer, ion transfer and membrane studies. Some fundamental physicochemical properties of liquid/liquid systems were explored. For electron transfer reactions the dependence of the rate of electron transfer on supporting electrolyte concentration in the organic phase for the water/1,2-DCE interface was measured using the technique of interfacial electrochemical impedance spectroscopy. No dependence of the rate of electron transfer on the concentration of the supporting electrolyte in the organic phase was observed. The effect of the solvent on the kinetics of electron transfer has also been examined. The results show that the rate does not follow the expected Marcusian dependence. Several solvents previously unused for liquid/liquid studies have been screened; one solvent in particular, 1,2-difluorobenzene, shows great promise for future work. The ion transfer studies show that platinates can be separated under potential control across the water/1,2-DCE and the water/methyl isobutyl ketone interfaces. Ion transfer and separation of chloroaurate and chloroplatinates have been discussed on the basis of the Galvani potential of ion transfer. Evidence of ion pairing between the platinates and the organic supporting electrolyte cation was found. The thermodynamics of the platinate transfer have also been explored and, in collaboration with Dr Robert Deeth, preliminary density functional theory calculations have been performed to explain the experimental results in terms of a model accounting for the surface charge density of the platinates. This goes further than the classical Born approach of treating the ion as a hard sphere of charge in a dielectric continuum. The ion transfer across membranes has been studied and the results were applied to single and dual membrane supported liquid/liquid interfaces for separating platinates from base metals. [PtCl6]2- transfer across a supported liquid membrane was demonstrated. The scale–up experiments were not successful, but if certain points can be addressed, it may be possible for future studies to build on what has been achieved here. Additional to the three traditional sections of liquid/liquid work, a method of preparing gold nanoparticles has been found using ketones as the reducing agent at the water/ketone interface. The formation of gold mirrors has been observed and nanoparticles have been isolated and characterised.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Mohd-Setapar, Siti H. "Reverse micelle liquid-liquid extraction of a pharmaceutical product." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/36143.

Повний текст джерела

Анотація:

Reverse micelle extraction has received considerable attention in recent years due to its ability to selectively solubilise solutes from an aqueous phase, and in the case of biomolecules to maintain their biological activities, This thesis reports the results from studies on the extraction of penicillin G from aqueous solution (forward extraction) and from the reverse micelle to a new aqueous solution (backward extraction), The extraction is influenced by the initial penicillin G concentration, the salt type and concentration in the aqueous phase, pH, and surfactant concentration. The results show that penicillin is an interfacially active compound that interacts with AOT, with the interfacial association being dependent on both pH and surfactant concentration. When the penicillin to surfactant concentration ratio [P]aq/[S] is high precipitation of the penicillin occurs. The distribution coefficient favours transfer of the penicillin into the reverse micelle at moderate AOT concentrations.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Zgonnik, Viacheslav. "Elle & il : enantioselective liquid-liquid extraction and ionic liquids." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1297/.

Повний текст джерела

Анотація:

L'extraction liquide-liquide énantiosélective (ELLE) consiste en l'extraction d'un énantiomère à partir d'un mélange racémique par transfert entre deux phases liquides. Cette technologie est très prometteuse pour l'obtention des composés énantiopurs et devient l'objet d'une forte attention les dernières années grâce au développement de l'équipement approprié qui permet de réduire le temps et le prix de la séparation des énantiomères. L'objectif essentiel pour l'introduction d'ELLE dans le monde industriel est la découverte d'hôtes chiraux fiables, peu chers, durables, sélectifs et applicables à une large gamme de substances chirales. Dans ce travail, la possibilité d'effectuer l'ELLE dans un milieu ionique chiral a été vérifiée. De nombreux nouveaux liquides ioniques chiraux ont été préparés pour jouer le rôle des hôtes chiraux. Le meilleur exemple montre un excès énantiomérique de 30% et une sélectivité opérationnelle de 1,97. Ceci représente le premier exemple d'ELLE utilisant les liquides ioniques chiraux et sans usage d'ions métalliques
Enantioselective liquid-liquid extraction (ELLE) is an implementation of the extraction of one enantiomer from a racemic mixture by the transfer between two liquid phases. This technology is very promising for obtaining enantiopure compounds and becomes the object of much attention in recent years after the development of appropriate equipment that reduces the time and cost of the separation of enantiomers. The major objective for the successful introduction of ELLE to industrial world is the discovery of reliable, inexpensive and durable chiral hosts selective for a wide range of chiral substances. In this work the possibility of performing ELLE in chiral ionic liquids environment was verified. Many new chiral ionic liquids were prepared to play the role of chiral hosts. The best example shows enantiomeric excess of 30% and operational selectivity of 1. 97. This represents the first example of using chiral ionic liquids in ELLE and without metallic ions

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Tucker, Kate Louise. "Heavy metal extraction using advanced liquid-liquid style partitioning systems." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/heavy-metal-extraction-using-advanced-liquid--liquid-style-partitioning-systems(6a238cb4-94cf-4fa8-bffe-d1a1b70adaa6).html.

Повний текст джерела

Анотація:

Understanding the behaviour of heavy metals involved in the nuclear fuel cycle is of paramount importance to the reprocessing and storage of spent nuclear fuel. These studies have attempted to obtain a greater understanding of the fundamental chemistry of these systems, by investigating extraction performance and speciation in current (PUREX) and proposed (GANEX) extraction processes. Various complexes have been shown to exist in the post-extracted organic fraction of the systems analysed. For Zr(IV), U(VI) and Np(VI) separated from aqueous nitric and hydrochloric using TBP, the complexes [Zr(NO3/Cl)4(TBP)4], [UO2(NO3/Cl)2(TBP)2] and [NpO2(NO3/Cl)2(TBP)2] formed, respectively. For Zr(IV) separated from aqueous mixtures of HNO3 and HCl at equal concentration, a preference was shown to [Zr(Cl)4(TBP)4] over the analogous nitrate complex. For U(VI) separated from aqueous mixtures of HNO3 and HCl, a preference was shown to [UO2(Cl)2(TBP)2], even at high aqueous nitrate concentrations. NMR data for Pu(IV) separated from aqueous HNO3, HCl and mixtures of both, using TBP were presented, where possible complexation was observed. It is thought that [Pu(NO3)4(TBP)4] or [PuCl4(TBP)4] species existed within the organic fraction for Pu(IV) separated from aqueous HNO3 and HCl, respectively. These systems showed high distribution ratios where an increase was observed with increasing aqueous acid concentration overall. Distribution ratio data were presented for the lanthanide series separated from aqueous nitric acid, using the proposed GANEX solvent system(s). The lanthanides analysed showed an increase in distribution ratio with increasing aqueous nitric acid concentration and with increasing TODGA concentration in the organic fraction. Heavier lanthanides were observed to give higher distribution ratios overall. The best distribution ratios were observed for lanthanides separated using 0.2 M TODGA with 1-octanol (5 % by volume) over the nitric acid concentration range analysed. For lanthanides separated using 0.5 M DMDOHEMA, an optimum distribution ratio was observed at around 6 M aqueous nitric acid concentration. The distribution ratio data for lanthanides separated from a range of DMDOHEMA concentrations, were observed to increase with increasing organic DMDOHEMA concentration. The distribution ratios observed for isotopes of Np, Am, Eu and Pu separated using 0.2 M TODGA, increased with increasing aqueous nitric acid concentration. The same trend was observed for the aforementioned isotopes separated using 0.5 M DMDOHEMA. However, pertechnetate separated using 0.2 M TODGA from aqueous nitric acid, showed a decrease in the distribution ratios observed over the acid concentration range analysed. This was contrary to pertechnetate separated from aqueous nitric acid using 0.5 M DMDOHEMA, where a small increase in distribution ratio was observed over the concentration range analysed. For Np(VI) separated from some proposed GANEX solvents, the 0.2 M TODGA/0.5 DMDOHEMA combination gave the best distribution of neptunium into the organic fraction. For Np(VI) separated using 0.5 M DMDOHEMA, the complex [Np(DMDOHEMA)2(NO3)4] was observed. Additional attempts to analyse Np(VI) behaviour under GANEX style conditions via EXAFS, were not successful due to immediate reduction of the Np(VI) on the beam line.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Desouky, Osman Abd El-Naby. "Liquid-liquid extraction of rare earth elements from sulfuric acid." Thesis, University of Leeds, 2006. http://etheses.whiterose.ac.uk/638/.

Повний текст джерела

Анотація:

This thesis is concerned with the liquid-liquid extraction and separation of Y, Ce, La, binary mixtures, and ternary mixtures as well as synthesis of novel amide ligands for the extraction of rare earth elements. Chapter I is the general introduction of the practical process and applications of solvent extraction and its theory. It describes systems involving compound formation, ion-association and solvation as well as solvent loading capacity, dispersion and coalescence. The aims of this thesis are also presented. Chapter 2 presents an introduction to yttrium chemistry and recent developments in yttrium extraction chemistry. It describes the relevant factors affecting the liquidliquid extraction process to determine the optimum conditions for yttriurn extraction from sulfate liquor. These factors include TiOA concentration, contact time, pH value, temperature, aqueous phase composition, diluent and construct of McCabe-Thiele diagram. In addition, the synergistic effect of using TBP, TOPO and D2EHPA and the optimum conditions for the stripping process are deten-nined. Chapter 3 contains introduction to cerium chemistry and recent developments in cerium extraction chemistry. The optimum conditions for solvent extraction of cenum(III) from a sulfate medium, and synergistic effects using TOPO and D2EHPA on the extraction process are studied. Also, the relevant factors affecting cerium(Ill) stripping efficiency are determined. Chapter 4 presents a brief introduction to lanthanum and recent developments in lanthanum extraction chemistry. The optimum conditions for solvent extraction of lanthanum from sulfate media, with synergistic effects using TOPO, D2EHPA and TBP are described. In addition, the suitable conditions for the lanthanum stripping process are determined. Chapter 5 contains the principles of separation and liquid-liquid extraction of binary (Y/La) and ternary (Nd-La-Y) element systems. The optimum conditions for the separation of both systems were investigated. Chapter 6 describes the synthesis and characterization of several novel piperazine and piperidine amide ligands. These ligands have good extraction ability for both light and heavy rare earth elements. The optimum conditions for solvent extraction of yttnum and cerium(III) using these ligands were studied. The chapter also, contains the experimental procedures and characterising data for ligand synthesis in this thesis.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Vadon, Mathieu. "Extraction de bore par oxydation du silicium liquide pour applications photovoltaïques." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI067/document.

Повний текст джерела

Анотація:

L'extraction du bore du silicium liquide est une étape d'une chaîne de procédés de purification de silicium de qualité suffisante pour les applications photovoltaïques. Cette thèse étudie en priorité le procédé dit "gaz froid" qui consiste en l'injection d'un mélange de gaz Ar-H2-H2O sur du silicium liquide chauffé électromagnétiquement. Une deuxième méthode similaire ("procédé plasma") où on injecte un plasma thermique issu d'un mélange Ar-H2-O2 a également été étudiée. Un modèle est nécessaire afin d'optimiser le procédé pour économiser de l'énergie.Les trois objectifs du modèle sont la prédiction du flux de silicium issu de la surface (vitesse d'oxydation), du flux de bore issu de la surface (pour avoir la vitesse de purification), et du seuil de passivation. Le seuil de passivation est la limite de concentration d'oxydant au-delà de laquelleil apparait une couche de silice passivante qui empêche la purification. Afin de minimiser la consommation d'énergie en accélérant le procédé, on cherche à injecter une concentration d'oxydant juste en dessous du seuil de passivation.De précédentes études ont montré que le facteur limitant pour les flux de bore et de silicium est le transport d'oxydant dans la phase gaz. Ainsi, nous avons fait un modèle monodimensionnel réactif-diffusif à l'équilibre thermodynamique de la couche limite gazeuse. Selon ce modèle, l'effet de la formation d'aérosols de silice est de diviser par deux le flux d'oxydant vers la surface, ce qui sert aux simulations CFD. Cet effet des aérosols de silice sur les flux d'oxydant peut aussi se retrouver si on enlève l'hypothèse d'équilibre thermodynamique des aérosols de silice avec la phase gaz, ce qui est confirmé par des simulations CFD et des expériences.Pour ce qui concerne l'estimation de la vitesse de purification, les données les plus réalistes concernant l'enthalpie de formation de HBO(g) et le coefficient d'activité du bore dans le silicium liquide ont été sélectionnées. Nous obtenons une bonne prédiction de la vitesse de purification à différentes températures et concentrations d'oxydant, y compris pour le cas plasma que nous avons étudié, en utilisant ces données thermodynamiques et en supposant que les produits de réaction de surface SiO(g) et HBO(g) diffusent de manière similaire. Ces coefficients de transfert identiques pour HBO(g) et SiO(g) peuvent s'expliquer par une précipitation simultanée et commune de HBO(g) et SiO(g), selon des mécanismes de germination et croissance restant à déterminer.Un dispositif expérimental de lévitation électromagnétique de silicium sous un jet oxydant a été monté. La mesure et le contrôle de température d'une bille de silicium ont été mis en oeuvre ce qui permettra la mesure sans contaminations de données thermodynamiques concernant les impuretés .Le seuil de passivation mesuré sur quelques expériences disponibles peut être prédit par notre modèle d'oxydation (associé au facteur deux représentant les aérosols de silice), si on l'associe à un critère proposé dans la littérature, qui couple la fraction du flux d'oxydant arrivant à la surface à une loi d'équilibre entre SiO(g), Si(l) et SiO2(s/l). Nous montrons dans cette thèse que la couche passivante n'est compatible avec des aérosols de silice que si ces aérosols ne sont pas en équilibre avec la phase gaz. La cinétique de formation des aérosols de silice doit donc être étudiée plus en détails
Boron extraction from liquid silicon is a step within a new chain of processes aimed to purify silicon that meets purity requirements specific to photovoltaic applications. This thesis focuses mostly on cold gas processes that involve the injection of a mixture of Ar-H2-H2O gases onto electromagnetically stirred liquid silicon. A second similar method ("plasma processes") that involves the injection of thermal plasma made from an Ar-H2-H2O mixture has also been studied. A model is needed to minimize energy consumption by optimizing the process.We want to be able to predict the flow of silicon from the reactive surface (oxidation speed), the flow of boron from the surface (to have the purification speed) and the passivation threshold. For a given setting, the passivation threshold is the limit oxydant partial pressure at injection beyond which a passivating silica layer appears on the surface of the liquid silicon, which interrupts the purification. In order to minimize the energy consumption, and for that matter , in order to speed up the process, we want to inject oxydant in a quantity just below the passivation threshold.Previous studies have shown that the limiting factor for the oxidation and purification speed is the transport of oxidant in the gas phase. That's why we have made a 1D reactive-diffusive model at thermodynamical equilibrium of the gaseous boundary layer. According to this model the effect of the formation of silica aerosols is to divide by two the flow of oxydant towards the surface, which is useful for the simplification of CFD simulations. This effect of the formation of silica aerosols on oxidant flows can also be found without the hypothesis of thermodynamical equilibrium of silica aerosols with the gas phase, as confirmed by simulations and experiments.Regarding the estimation of the purification speed, we have selected the most realistic values of the enthalpy of formation of HBO(g) and of the activity coefficient of boron in liquid silicon.We could get good estimates of the purification speed at different temperatures and levels of oxidant concentrations at injection, by using the selected thermodynamical values and by supposing that the surface reaction products HBO(g) and SiO(g) diffuse similarly. A reason for this similar diffusion of SiO(g) and HBO(g) might be a common and simultaneous precipitation , due to specific dynamics of nucleation and growth that need to be investigated further. Those results for cold gas processed could also be obtained for a plasma experiment.However for the plasma experiment, silica aerosols can be formed only in a very thin layer near the surface and this result needs confirmation from other experiments.Temperature measurement and control for electromagnetically levitating liquid silicon under a flow of oxidant were achieved. With more time, quantitative results could be achieved to measure thermodynamical data on impurities without contaminations.Regarding the prediction of the passivation threshold, we justified a thermodynamical equilibrium at surface of SiO(g) with Si(l) and SiO2(s/l) at passivation threshold with the spreading of silica particles over the liquid silicon surface with the stirring. We show that the passivation layer is compatible with silica aerosols only if those aerosols are not in equilibrium with the gas phase. Therefore the kinetics of formation of silica aerosols should be studied further. A previous empirical formula on the prediction of the passivation threshold for experiments where H2O is the oxidant has been confirmed using our CFD model. A passivation experiment has shown the absence of impact of silica aerosols on oxidant transport when the oxidant is O2

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Kuhn, Jay C. "Experimental design for the study of extraction efficiencies of the continuous liquid-liquid extractor." Master's thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-01202010-020253/.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Zaidi, Muthana Getan Mohammed. "Methodology of synthesis and selection of solvents for liquid-liquid extraction." Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333314.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Oloidi, Jimmy O. "A study of liquid-liquid extraction in a sieve plate column." Thesis, Aston University, 1987. http://publications.aston.ac.uk/10226/.

Повний текст джерела

Анотація:

The literature relating to sieve plate liquid extraction columns and relevant hydrodynamic phenomena have been surveyed. Mass transfer characteristics during drop formation, rise and coalescence, and related models were also reviewed. Important design parameters i.e. flooding, dispersed phase hold-up, drop size distribution, mean drop size, coalescence/flocculation zone height beneath a plate and jetting phenomena were investigated under non-mass transfer and mass transfer conditions in a 0.45m diameter, 2.3m high sieve plate column. This column had provision for four different plate designs, and variable plate spacing and downcomer heights, and the system used was Clairsol `350' (dispersed) - acetone - deionised water (continuous) with either direction of mass transfer. Drop size distributions were best described by the functions proposed by Gal-or, and then Mugele-Evans. Using data from this study and the literature, correlations were developed for dispersed phase hold-up, mean drop size in the preferred jetting regime and in the non-jetting regime, and coalescence zone height. A method to calculate the theoretical overall mass transfer coefficient allowing for the range of drop sizes encountered in the column gave the best fit to experimental data. This applied the drop size distribution diagram to estimate the volume percentage of stagnant, circulating and oscillating drops in the drop population. The overall coefficient Kcal was then calculated as the fractional sum of the predicted individual single drop coefficients and their proportion in the drop population. In a comparison between the experimental and calculated overall mass transfer coefficients for cases in which all the drops were in the oscillating regime (i.e. 6.35mm hole size plate), and for transfer from the dispersed(d) to continuous(c) phase, the film coefficient kd predicted from the Rose-Kintner correlation together with kc from that of Garner-Tayeban gave the best representation. Droplets from the 3.175mm hole size plate, were of a size to be mainly circulating and oscillating; a combination of kd from the Kronig-Brink (circulating) and Rose-Kintner (oscillating) correlations with the respective kc gave the best agreement. The optimum operating conditions for the SPC were identified and a procedure proposed for design from basic single drop data.

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Boey, Sek Chew. "Citric acid extraction by liquid membranes." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47363.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Wächtler, Timo [Verfasser]. "Numerical Simulation of Turbulent Dispersions in Liquid-Liquid Extraction Columns / Timo Wächtler." München : Verlag Dr. Hut, 2014. http://d-nb.info/1055863168/34.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Tizvar, Roza. "Investigation of liquid-liquid extraction process for separation of glycerol and biodiesel." Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27490.

Повний текст джерела

Анотація:

Biodiesel is a sustainable and environmentally friendly source of energy which is now being used as an alternative for fossil fuels worldwide. Glycerol is the main by-product of biodiesel produced via transesterification and must be removed from biodiesel according to the ASTM Standard D-6751-02. This purification has usually been carried out with liquid-liquid extraction with water as a solvent for glycerol. In commonly-used alkali-catalyzed transesterification of waste cooking oil, the use of large quantities of water alone, as extraction solvent, results in formation of soaps, then emulsions and further difficulties in process downstream. This problem does not exist in acid-catalyzed transesterification of waste cooking oil. The main objective of the current study was to evaluate the efficiency of other potential solvents, such as hexane and methanol, as well as water in a liquid-liquid extraction unit for separation of glycerol and biodiesel. In order to accomplish this task, first of all, the reliability of the UNIFAC activity coefficient model to predict the phase equilibria of such systems was evaluated. The technical feasibility of the use of hexane, methanol and water as solvents in a single-stage mixer-settler was then investigated. The biodiesel was produced via acid-catalyzed transesterification of waste cooking oil with methanol and the stream entering the mixer was assumed to be free of unconverted oil and acid catalyst, containing only biodiesel, glycerol and methanol. Furthermore, the biodiesel was assumed to have the properties of methyl oleate, which is the major component of biodiesel made from canola oil and methanol. The ASTM limit for glycerol content of biodiesel (<0.02 wt%), the residence time in the settler, the ratio of the liquid phase volumes in the settler and the biodiesel loss were the major performance measures considered. Four different solvent systems were found suitable: (1) water combined with residual methanol (with optimal mass ratio of biodiesel:methanol:water of 1:0.10:0.97), (2) a mixture of hexane and methanol (with optimal mass ratio of biodiesel:hexane:methanol of 1:1.15:1.62), (3) a mixture of hexane and water combined with residual methanol (with optimal mass ratio of biodiesel:hexane:methanol:water of 1:0.79:0.10:0.69) and (4) a mixture of hexane, methanol and water (with optimal mass ratio of biodiesel:hexane:methanol:water of 1:2.27:0.87:0.30). In acid-catalyzed production of biodiesel from waste cooking oil and methanol, the units located following the mixer-settler were designed and used in the economic evaluation of the entire biodiesel plant. The technically feasible solvent systems were then optimized based on maximizing the after-tax return on investment as a measure of the annual profitability. Although all the processes showed poor economic potentials with negative annual after-tax return on investment, the relative values were important to compare these processes. The biodiesel plants using hexane and water solvents combined with residual methanol or additional methanol with optimal biodiesel:hexane:methanol: water mass ratio of 1:0.43:0.10:0.24 or 1:2.19:0.90:0.34, respectively, yielded the highest annual after-tax return on investment of -35%. The process using water combined with residual methanol, with optimal mass ratio of biodiesel:methanol:water of 1:0.10:0.86 showed to be the least economically beneficial system, mainly because of its relatively low annual revenue and low total capital investment. In contrast, the process using water combined with residual methanol and the process using a mixture of hexane and water combined with additional methanol yielded the lowest and the highest biodiesel break-even prices of 1.70 and 1.91 $/L, respectively.

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Watts, Frank. "The effect of electrical potential on mass transfer in liquid-liquid extraction." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/10283.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Göklen, Kent Emir. "Liquid-liquid extraction of biopolymers : selective solubilization of proteins in reverse micelles." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15103.

Повний текст джерела

Анотація:

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1986.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 297-308.
by Kent Emir Göklen.
Ph.D.

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Wächtler, Timo Frederik [Verfasser]. "Numerical Simulation of Turbulent Dispersions in Liquid-Liquid Extraction Columns / Timo Wächtler." München : Verlag Dr. Hut, 2014. http://d-nb.info/1055863168/34.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Hanif, Mohammed. "Mass transfer studies in solvent extraction." Thesis, Teesside University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328022.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Slaymaker, Elizabeth Ann. "Effects of surface active agents on drop size in liquid-liquid systems." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/10260.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Kanel, Jeffrey Scott. "Effects of some interfacial phenomena on mass transfer in agitated liquid-liquid dispersions." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/11257.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Дисертації з теми "Liquid/liquid extraction purification"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями