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Dzyazko, Yu S., L. N. Ponomareva, Yu M. Volfkovich, V. N. Belyakov, V. E. Sosenkin, N. F. Nikolskaya, N. N. Scherbatyuk, and Yu A. Litvinenko. "Hybrid organic-inorganic nanocomposites for ion-exchange processes." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20577.
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Two types of composite ion-exchangers, which are based on strongly acidic gellike cation-exchange resin and zirconium hydrophosphate, have been obtained. The first group contains both inorganic nanoparticles and their aggregates, the second one contains only aggregates. Analysis of differential porogrammes obtained with a method of standard contact porometry allowed us to estimate porous structure both of polymer
matrix and inorganic constituent. Each stripe of the porogrammes has been related to structure element of polymer and ZrPh. Geometrical globular model has been applied to estimate a size of nanoparticles. A size of the nanoparticle size was shown to depend on their location: it reaches 16 nm, if the globules are placed in clusters of the polymer matrix, and 36 nm for aggregated nanoparticles in macropores. The results have been
confirmed by data of scanning and transmission electron microscopy. Modification of ion-exchange resins causes transformation of porous structure of labile polymer matrix.
The transformation occurs both at nano- and micro-levels. Recommendations regarding to structure of composite ion-exchangers for different applications are given.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20577
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Van, Den Bosch Magali Marie. "Simulation of ion exchange processes using neuro-fuzzy reasoning." Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/2161.
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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2009.Neuro-fuzzy computing techniques have been approached and evaluated in areas of process control; researchers have recently begun to evaluate its potential in pattern recognition. Multi-component ion exchange is a non-linear process, which is difficult to model and simulate as there are many factors influencing the chemical process which are not well understood. In the past, empirical isotherm equations were used but there were definite shortcomings resulting in unreliable simulations. In this work, the use of artificial intelligence has therefore been researched to test the effectiveness in simulating ion exchange processes. The branch of artificial intelligence used was the adaptive neuro fuzzy inference system. The objective of this research was to develop a neuro-fuzzy software package to simulate ion exchange processes. The first step towards building this system was to collect data from laboratory scale ion exchange experiments. Different combinations of inputs (e.g. solution concentration, resin loading, impeller speed), were tested to determine whether it was necessary to monitor all available parameters. The software was developed in MSEXCEL where tools like SOLVER could be utilised whilst the code was written in Visual Basic. In order to compare the neuro-fuzzy simulations to previously used empirical methods, the Fritz and Schluender isotherm was used to model and simulate the same data. The results have shown that both methods were adequate but the neuro-fuzzyapproach was the more appropriate method. After completion of this study, it could be concluded that a neuro-fuzzy system does not always have the ability to describe ion exchange processes adequately.
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Hastie, Michele. "Energy and Water Conservation in Biodiesel Purification Processes." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20384.
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Biodiesel purification processes generate wastewater streams that require a large amount of energy when distillation is used as a treatment technology. Process simulation software was used to show that an alternative water treatment process involving ion exchange would require only 31% of the energy used by distillation. Experiments showed that multiple washing stages were required to meet the standard specification for sodium, an impurity present in crude biodiesel, when washing biodiesel made from used frying oil. A comparison was made between washing biodiesel in a cross-current washing configuration and a counter-current configuration. Both configurations met the specification for sodium within three washing stages; however, the counter-current configuration required less water, making it the more efficient process. Lastly, the removal of sodium from wastewater samples using an ion exchange resin was experimentally investigated. The results validated the use of ion exchange to reduce energy consumption in biodiesel purification.
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Steinwinder, Thomas Riemann Zhao Dongye. "Engineered treatment of As-laden regeneration brine from ion exchange processes." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/master's/STEINWINDER_THOMAS_33.pdf.
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Yip, Ngai Yin. "Sustainable Production of Water and Energy with Osmotically-Driven Membrane Processes and Ion-Exchange Membrane Processes." Thesis, Yale University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3582181.
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The world population of the 21st century is facing an increasingly challenging energy landscape and declining water quality and availability, further compounded by a rapidly expanding global population against the backdrop of climate change. To meet the challenges of the water-energy nexus in a sustainable manner, existing methods need to be advanced and new technologies developed. Osmotically-driven and ion-exchange membrane processes are two classes of emerging technologies that can offer cost-effective and environmentally sensible solutions to alleviate the pressure on our water and energy demands. The objective of this thesis is to advance forward osmosis (FO), pressure retarded osmosis (PRO), and reverse electrodialysis (RED) for the sustainable production of water and energy.
A main hindrance restricting the progress of osmotically-driven membrane processes, FO and PRO, is the absence of adequate membranes. This work demonstrates the fabrication of thin-film composite polyamide FO membranes that can attain high water flux and PRO membranes capable of achieving power density of 10 W/m2, twice the benchmark of 5 W/m2 for PRO with natural salinity gradients to be cost-effective. A membrane fabrication platform based on mechanistic understanding of the influence of membrane transport and structural parameters on process performance was developed. The morphology and microstructure of the porous support layer, and hydraulic permeability and salt selectivity of the polyamide active layer were specifically tailored by thoughtful control of the fabrication and modification conditions.
The Gibbs free energy from the mixing of river water with seawater can potentially be harnessed for clean and renewable energy production. This work analyzed the thermodynamics of PRO power generation and determined that energy efficiencies of up to ∼91% can theoretically be attained. The intrinsic limitations and practical constraints in PRO were identified and discussed. Using a tenth of the annual global river water discharge of 37,000 km 3 for PRO could potentially produce electricity for over half a billion people, ascertaining natural salinity gradients to be a sizeable renewable source that can contribute to diversifying our energy portfolio.
However, fouling of the membrane support layer can diminish the PRO productivity by detrimentally increasing the hydraulic resistance. Analysis of the water flux behavior and methodical characterization of the membrane properties shed light on the fouling mechanism and revealed the active-support layer interface to play a crucial role during fouling. A brief osmotic backwash was shown to be effective in cleaning the membrane and achieving substantial performance recovery.
Reverse electrodialysis (RED) is an ion-exchange membrane process that can also extract useful work from salinity gradients. This dissertation research examined the energy efficiency and power density of RED and identified a tradeoff relation between the two performance parameters. Energy efficiency of ∼33-44% can be obtained with technologically-available membranes, but the low power densities of < 1 W/m2 is likely to be impede the realization of the process. To further advance RED as a salinity energy conversion method, ion-exchange membrane technology and stack design need to be advanced beyond their current limitations.
When analyzed with simulated existing state-of-the-art membranes, PRO exhibited greater energy efficiencies (54-56%) and significantly higher power densities (2.4-38 W/m2) than RED (18-38% and 0.77-1.2 W/m 2). The drawback of RED is especially pronounced at large salinity gradients, where the high solution concentrations overwhelm the Donnan exclusion effect and detrimentally diminish the ion exchange membrane permselectivity. Additionally, the inherent different in driving force utilization (osmotic pressure difference for PRO and Nernst potential for RED) restricts RED from exploiting larger salinity gradients to enhance performance. Overall, PRO is found to be the more favorable membrane-based technology for accessing salinity energy.
This work presents pioneering advances for forward osmosis and pressure retarded osmosis membrane development. The fundamental studies of the osmotically-driven membrane processes and ion-exchange membrane processes yielded significant findings that enhanced our mechanistic and thermodynamic understanding of the technologies. The important insights can serve to inform the realization of the emerging membrane-based technologies for the sustainable production of water and energy. The implications of the thesis are potentially far-reaching and are anticipated to shape the discussion on FO, PRO, and RED.
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Bhumgara, Zubin Godrej. "A study of the development of polyhipe foam materials for use in separation processes." Thesis, University of Exeter, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263147.
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Marinetti, Andrea. "Recovery of Carboxylic acids from anaerobic fermented broth through ionic exchange processes." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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The recovery of Carboxylic acids were based on two particular objective: the study of the efficiency of a cation exchange resin, used in order to reduce the pH of the actual effluent, considering it is necessary to have a low pH for the anion exchange resin to be able to adsorb the acids from the effluent, and the preliminary studies perfomerd on the anion exchange resin, at various flow rates and both mode of operation, expanded and packed bed mode, using a simulated effluent, were the carboxylic acids were represented by just acetic acid, as the target molecule.
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Tervonen, Ari. "Optical waveguides by ion exchange in glass fabrication processes for integrated optics applications /." Helsinki : Finnish Society of Sciences and Letters, 1990. http://catalog.hathitrust.org/api/volumes/oclc/35476660.html.
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Naughton, Elise Michele. "Ru,Rh,Ru Supramolecular Photocatalysts within Nafion® Membranes: Ion-exchange, Photoelectrolysis and Electron Transfer Processes." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/70865.
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Perfluorosulfonate ionomers, such as Nafion® have been shown to demonstrate a profound affinity for large cationic complexes, and the study of polymer-bound cations may provide insight regarding Nafion® morphology by contrasting molecular size with existing models. The trimetallic complex, [{(bpy)2Ru(dpp)}2RhBr2] 5+, is readily absorbed by ion exchange into Na+ -form Nafion® membranes under ambient conditions. The dimensions of three different isomers of the trimetallic complex are estimated to be: 23.6 Å × 13.3 Å × 10.8 Å, 18.9 Å × 18.0 Å × 13.7 Å, and 23.1 Å × 12.0 Å × 11.4 Å, yielding an average molecular volume of 1.2×103 Å3 . At equilibrium, the partition coefficient for the ion-exchange of the trimetallic complex into Nafion® from a DMF solution is 5.7 × 103 . Furthermore, the total cationic charge of the exchanged trimetallic complexes counterbalances 86 ± 2% of the anionic SO3 − sites in Nafion®. The characteristic dimensions of morphological models for the ionic domains in Nafion® are comparable to the molecular dimensions of the large mixedmetal complexes. Surprisingly, SAXS analysis indicates that the complexes absorb into the ionic domains of Nafion® without significantly changing the ionomer morphology. Given the profound affinity for absorption of these large cationic molecules, a more open-channel model for the morphology of perfluorosulfonate ionomers is more reasonable, in agreement with recent experimental findings. In contrast to smaller monometallic complexes, the time- v dependent uptake of the large trimetallic cations is biexponential. This behavior is attributed to a fast initial ion-exchange process on the surface of the membrane, accompanied by a slower, transport-limited ion-exchange for sites in the interior of the ionomer matrix.
The development of Nafion®/[{(bpy)2Ru(dpp)}2RhBr2] 5+ modified electrodes is also described for both FTO electrodes and materials made from electrospun carbon mats. The [{(bpy)2Ru(dpp)}2RhBr2] 5+ complexes behave as photocatalytic hydrogen production catalysts in the Nafion® membrane. Furthermore, a second bulk photoelectrolysis experiment with the Nafion®/[{(bpy)2Ru(dpp)}2RhBr2] 5+/FTO electrodes shows an enhancement of catalytic activity compared to the first photoelectrolysis experiment. This enhancement is attributed to halide loss following the first reduction process. Lastly, electrospun carbon nanofiber mats behave as electron donor materials for [{(bpy)2Ru(dpp)}2RhBr2] 5+/Nafion® membranes.Ph. D.
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Payne, Karl A. "Mathematical and Numerical Modeling of Hybrid Adsorption and Biological Treatment Systems for Enhanced Nitrogen Removal." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7702.
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High nutrient loading into groundwater and surface water systems has deleterious impacts on the environment, such as eutrophication, decimation of fish populations, and oxygen depletion. Conventional onsite wastewater treatment systems (OWTS) and various waste streams with high ammonium (NH4+) concentrations present a challenge, due the inconsistent performance of environmental biotechnologies aimed at managing nutrients from these sources.
Biological nitrogen removal (BNR) is commonly used in batch or packed-bed reactor configurations for nitrogen removal from various waste streams. In recognition of the need for resource recovery, algal photobioreactors are another type of environmental biotechnology with the potential for simultaneously treating wastewater while recovering energy. However, irrespective of the technology adopted, outstanding issues remain that affect the consistent performance of environmental biotechnologies for nitrogen removal and resource recovery. In OWTS, transient loading can lead to inconsistent nitrogen removal efficiency, while the presence of high free ammonia (FA) can exert inhibitory effects on microorganisms that mediate transformation of nitrogen species as well as microalgae that utilize nitrogen. Therefore, to overcome these challenges there have been experimental studies investigating the addition of adsorption and ion exchange (IX) media that can temporarily take up specific nitrogen ions.
Bioreactors comprised of microorganisms and adsorption/IX media can attenuate transient loading as well as mitigate inhibitory effects on microorganisms and microalgae; however, the interplay between physicochemical and processes in these systems is not well understood. Therefore, the main objective of this dissertation was to develop theoretical and numerical models that elucidate the complex interactions that influence the fate of chemical species in the bioreactors.
To achieve this objective and address the issues related to improving the understanding of the underlying mechanisms occurring within the environmental biotechnologies investigated, the following three research studies were done: (i) experimental and theoretical modeling studies of an IX-assisted nitrification process for treatment of high NH4+ strength wastewater (Chapter 3), (ii) theoretical and numerical modeling of a hybrid algal photosynthesis and ion exchange (HAPIX) process for NH4+ removal and resource recovery (Chapter 4), and (iii) mathematical and numerical modeling of a mixotrophic denitrification process for nitrate (NO3-) removal under transient inflow conditions (Chapter 5).
The experimental results for the IX-assisted nitrification process showed that by amending the bioreactor with zeolite, there was a marked increase in the nitrification rate as evidenced by an increase in NO3– production from an initial concentration of 3.7 mg-N L-1 to 160 mg-N L-1. This increase is approximately an order of magnitude greater than the increase in the reactor without chabazite. Therefore, the experimental studies provided support for the hypothesis that IX enhances the nitrification process. To garner further support for the hypothesis and better understand the mechanisms in the bioreactor, a novel mathematical model was developed that mechanistically describes IX kinetics by surface diffusion coupled with a nitrification inhibition model described by the Andrews equation. The agreement between the model and data suggests that the mathematical model developed provides a theoretically sound conceptual understanding of IX-assisted nitrification.
A model based on the physics of Fickian diffusion, IX chemistry, and algal growth with co-limiting factors including NH4+, light irradiance, and temperature was developed to describe a batch reactor comprised of microalgae and zeolite. The model can reproduce the temporal history of NH4+ in the reactor as well as the growth of microalgae biomass. The mathematical model developed for the HAPIX process balances between simplicity and accuracy to provide a sound theoretical framework for mechanisms involved.
In OWTS, transient inflow conditions have an influence on the performance of environmental biotechnologies for nitrogen removal. Prior experiments have shown that for denitrification, a tire-sulfur hybrid adsorption and denitrification (T-SHAD) bioreactor consistently removes nitrogen under varying influent flow and concentration conditions. To enhance the understanding of the underlying mechanisms in the T-SHAD bioreactor, a mathematical model describing mass transport of NO3- and SO42- in the aqueous phase and mixotrophic denitrification was developed. Additionally, a numerical tool to solve the mathematical model was implemented and compared to previously conducted experiments. Results from the numerical simulations capture the trend of the experimental data showing approximately 90% NO3- -N removal under varying flow conditions. Moreover, the model describes the effluent characteristics of the process showing a transient response in correspondence the changes in fluid velocity.
The new tools developed provide new insight into the underlying mechanisms of physical, chemical, and biological processes within these bioreactors. The tools developed in this dissertation have a potential broad impact in environmental biotechnology for wastewater treatment in on-site systems, for treatment of high strength wastewater, and can be extended easily for stormwater management systems aimed at mitigating high nutrient loading to the environment.
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Less, John Ryan. "Comparison of Natural Organic Matter (NOM) Removal Processes on Disinfection Byproduct (DBP) Formation During Drinking Water Treatment." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1293217404.
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ZINI, JOSIANE. "Usos das cromatografias de extracao e de troca ionica na separacao de torio e terras raras de residuos industriais gerados na unidade de purificacao de torio do IPEN. Aplicacao das terras raras como catalisadores na geracao de hidrogenio." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9532.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Choudhury, Asifur. "Removal of nickel and lead from natural clay soil through the introduction of EDTA and coupling ion exchange processes with electrokinetic methodology." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0007/MQ39473.pdf.
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Patil, Rahul. "Membrane Processes for Sustainable Energy Applications." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1353077392.
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Palli, Amar D. "Heteroatom removal from nonaqueous systems by sorption processes a comparative study of kinetic models." Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1179950186.
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VASCONCELLOS, MARI E. de. "Resolucao da mistura torio e terras raras por precipitacao fracionada e tecnologia de troca ionica." reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9276.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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MARTINS, PATRICIA de A. "Desenvolvimento de método para separação química de gálio-67 pela técnica de difusão térmica." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10147.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Martí, Calatayud Manuel César. "STUDY OF THE TRANSPORT OF HEAVY METAL IONS THROUGH CATION-EXCHANGE MEMBRANES APPLIED TO THE TREATMENT OF INDUSTRIAL EFFLUENTS." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/46004.
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La presente Tesis Doctoral consiste en la determinación de las propiedades de transporte de diferentes especies catiónicas a través de membranas de intercambio catiónico. Las membranas de intercambio iónico son un componente clave de los reactores electroquímicos y de los sistemas de electrodiálisis, puesto que determinan el consumo energético y la eficiencia del proceso. La utilización de este tipo de membranas para el tratamiento de efluentes industriales no es muy extendida debido a los requisitos de elevada resistencia química y durabilidad que deben cumplir las membranas. Otro asunto importante radica en la eficiencia en el transporte de los iones que se quieren eliminar a través de la membrana. Normalmente, existe una competencia por el paso a través de las membranas entre diferentes especies debido al carácter multicomponente de los efluentes a tratar. Sin embargo, una mejora en las propiedades de las membranas de intercambio iónico permitiría la implantación del tratamiento mediante reactores electroquímicos de efluentes industriales con un contenido importante en compuestos metálicos, tales como los baños agotados de las industrias de cromado. La utilización de una tecnología limpia como la electrodiálisis conllevaría diferentes ventajas, entre las cuales destacan la recuperación de los efluentes para su reutilización en el proceso industrial, el ahorro en el consumo de agua y la disminución de la descarga de contaminantes al medio ambiente.
La determinación de las condiciones de operación óptimas así como la mejora de las propiedades de transporte de las membranas constituye el principal tema de la presente investigación. Para ello, se emplearán diferentes tipos de membrana. En primer lugar, se estudiará el comportamiento de las membranas poliméricas comerciales que poseen unas propiedades de resistencia química elevadas, las cuales se tomarán como referencia. De forma paralela, se producirán membranas conductoras de iones a partir de materiales cerámicos económicos, ya que la resistencia de los materiales cerámicos a sustancias oxidantes y muy ácidas es mayor que la de los materiales poliméricos. Este punto constituye la parte más innovadora de la investigación, puesto que la mayoría de las membranas de intercambio iónico comerciales están basadas en materiales poliméricos que no pueden resistir las condiciones específicas de los efluentes industriales. Una vez determinadas las condiciones de operación óptimas, se realizarán ensayos en plantas piloto con el fin de confirmar los resultados obtenidos mediante las técnicas de caracterización y determinar el grado de recuperación y coste energético asociado a los procesos electrodialíticos de tratamiento de efluentes industriales.Martí Calatayud, MC. (2014). STUDY OF THE TRANSPORT OF HEAVY METAL IONS THROUGH CATION-EXCHANGE MEMBRANES APPLIED TO THE TREATMENT OF INDUSTRIAL EFFLUENTS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/46004
TESIS
Premiado
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Wakkel, Manel. "Contribution à l'étude de la séparation des protéines par chromatographie d'échange d'ions en milieu complexe. Effet du poids moléculaire sur l'équilibre et la cinétique de rétention." Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0023/document.
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La séparation et la purification de biomolécules à partir de milieux bruts, végétaux ou biologiques, est un sujet vaste etcomplexe. De sa compréhension et de son développement dépendent des enjeux industriels, et notamment le completdéveloppement des procédés biotechnologiques, les procédés de séparation, ou downstream processes, constituant environ 80% des coûts totaux de ces procédés. Ce travail se veut une contribution à ces problématiques. Il a été motivé par des résultatsobtenus au préalable dans le laboratoire qui montraient qu’il est possible de récupérer une protéine de très grande taille àpartir d’un milieu réel végétal par l’application d’une seule opération chromatographique (Kerfai, 2011). Suite à ce résultat,des hypothèses ont été énoncées, auxquelles ce travail essaie de répondre : quel(s) mécanisme(s) peuvent expliquer cerésultat ? Existe-t-il une localisation spécifique pour la fixation de la molécule sur l’échangeur d’ions qui rend plus simple etefficace sa récupération lors de l’étape d’élution ? Ainsi, notre objectif a été de progresser dans la connaissance des aspectsfondamentaux de la chromatographie d’échange d’ions appliquée à la séparation des protéines à partir d’un milieu brut.Notamment, l’influence de la présence d’autres protéines dans le milieu a été analysée, et ce dans le cas particulier deprotéines de poids moléculaire très différents, comme c’était le cas dans le travail précédemment cité. Des approches variées,théoriques et expérimentales à différentes échelles sur des milieux réels ou synthétiques, ont été appliquées et parfoisdéveloppées, pour essayer de répondre à ces questions. A l’échelle du procédé, une méthode statistique d’analyse desdonnées (Analyse en Composantes Principales ou ACP) a été menée, dont l’exploitation reste délicate. A l’échelle dulaboratoire, l’étude de l’équilibre et de la cinétique d’échange d’ions a été menée sur des solutions synthétiques de deuxprotéines : la sérum albumine bovine (BSA) (en tant que protéine de référence, couramment étudiée) et la ferritine (protéinede stockage du fer) de point isoélectrique proche de celui de la BSA mais de masse molaire plus élevée. Les résultatsmontrent que des modèles relativement classiques peuvent être appliqués, y compris pour les protéines de très grandes tailles,pour expliquer les aspects cinétiques de l’échange. Le couplage des flux de matière des protéines à l’intérieur des particulesde l’échangeur est très probable, malgré des diffusivités très différentes. Interpréter les résultats d’équilibre reste bien plusardu. La concentration en sel ou la présence de la BSA n’ont que très peu d’effet sur la rétention de la ferritine à l’équilibre.En revanche, la présence de la ferritine affecte très fortement la rétention de la BSA (pourtant plus favorable). Parmi lesphénomènes suggérés dans la littérature, l’effet Vroman a été recherché, mais il n’a pas été constaté dans le système pour lesconditions de travail utilisées. Les isothermes d’adsorption en conditions compétitives n’ont pas pu être simulées par lesmodèles habituels (comme l’isotherme multi-constituants de Langmuir), alors que celles des protéines seules sont tout à faitclassiques. En outre, un blocage partiel des pores de la résine par la ferritine reste probable, empêchant la diffusion de laBSA. Afin de vérifier ce dernier point, une méthodologie a été développée afin d’observer à l’échelle microscopique lesprofils de concentration des éléments représentatifs du système (P, Fe, Cl…) dans les particules. Cette méthode qui se trouveà un stade très avancé de développement, n’a pas encore permis de conclure faute de sensibilité suffisante des sondes àdispositionBioseparations from crude media, vegetable or biological, is a large and complex subject. Future industrial issues depend ontheir understanding and development, namely for biotechnological processes as downstream processes represent up to 80 %of their total cost. This work hopes to contribute to these general questions. It is justified by previous results obtained in thelaboratory showing that it is possible to recover a high molecular weight (HMW) protein from a complex vegetal juice in justone chromatographic operation. Hypotheses have been formulated, to which this work tries to answer: what mechanism couldexplain this behaviour? Is-there a specific location inside particles for the uptake of such protein, facilitating the recoveryduring elution step? Our objective has been to progress on the knowledge of fundamental questions concerning ion-exchangechromatography and their applications for proteins recovery from complex media. The effect of the other proteins in solutionhas been analysed, specifically in the situation where both proteins have a very different molecular weight, as in the previouscited work. Theoretical and experimental approaches, at various scales, have been applied or developed on real or syntheticsystems in order to answer some of these questions. At the process scale, a statistical method for data analysis (PrincipalComponent Analysis or PCA) has been applied. The complete interpretation of its results remains very hard. At thelaboratory scale, equilibrium and kinetics of ion exchange have been studied for synthetic solutions of two proteins: bovineserum albumin (BSA) (as reference protein widely studied), and ferritin (iron storage protein) having similar isoelectric pointas BSA but with higher molecular weight. Classical models for ion-exchange kinetics can explain the experimental results,even for HMW proteins. Mass transfer fluxes seem to be coupled for both proteins, even if they have usually very differentdiffusivities. The interpretation of equilibrium results is much more difficult. Equilibrium uptake of ferritin is not, or lightly,influenced by salt concentration or BSA content. Nevertheless, the presence of ferritin in the medium affects strongly BSAequilibrium uptake (however more favourable). Among the phenomena suggested in the literature, the Vroman effect hasbeen researched but it does not take place under the experimental conditions applied. Simulation of multi-componentisotherms has not been possible by classical models (such as multi-component Langmuir isotherm), while protein isothermsin single solution are standard. Besides, a partial blockage of the resin pores by ferritin is possible, preventing BSA diffusion.Therefore, a methodology has been developed at the microscopic scale, with the aim to observe concentration profiles forrepresentatives elements (P, Fe, Cl …) inside particles. The method, well developed, does not allow to conclude for themoment, because the probes used were not sensible enough
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El-Masri, Nasrein. "Ion-association complexes of thallium and mercury with rhodamine 6G in aqueous solution." Scholarly Commons, 1988. https://scholarlycommons.pacific.edu/uop_etds/2170.
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BABINSKI, MARLY. "Idades isocronicas Pb/Pb e geoquimica isotopica de Pb das rochas carbonaticas do grupo Bambui na porcao sul da bacia do Sao Francisco." reponame:Repositório Institucional do IPEN, 1993. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10339.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo
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Wells, Ricardo Angelo. "Comparison of distribution coefficients of 14 elements on three cation exchangers." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2641.
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Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2017.Certain resins used in ion-exchange separation techniques have become very expensive. Although ion-exchange is an economical method to soften water it is important to keep the cost low during the process. Any exorbitant costs will make a process unattractive and eventually obsolete. Bio-Rad AG MP-50 macroporous resin (supplied by Bio-Rad Laboratories, Ltd.) at present costs approximately R20000 (twenty thousand rand) for 500 g compared to Amberlyst 15 R840.00 for 500 mL and Dowex Marathon MSC R312.34 macroporous resin for 500 mL (both supplied by Dow, Rohm and Haas Co). This motivated the research to determine by a comparative study if there is any difference in the efficiency and effectiveness in the quantitative analysis of trace elements when these resins are used. The following elements will be used to determine distribution coefficients for the elements on these resins: Mn, Fe(III), Co, Ni, Cu, Zn, Al, Ag, Cd, In, Ga, Tl, Pb and Bi in 0.1, 0.2, 0.5, 1.0, 2.0, 3.0, 4.0 M nitric acid solutions. Another question is whether there is a difference or a preference when selecting either a microporous or a macroporous resin for the ion-exchange separation. Determination of distribution coefficients for 46 elements had been done by Strelow (Strelow F. W., 1984) in nitric acid on Bio-Rad AG 50W-X8. The results obtained in this study will be compared with the distribution coefficients obtained by Strelow. The Bio-Rad, Amberlyst and Dowex resins were stirred for approximately 30 minutes in deionised water and then packed in a column. Impurities in the resin column were eluted with 5 M HCl and the resin was then rinsed with deionised water to remove the acid. Thereafter the resins was rinsed out of the column with deionised water, filtered off and then dried under vacuum in an oven at 60 0C for approximately 24 hours. Stock solutions of the elements were prepared as 0.1 M solutions and then diluted with deionised water to obtain solutions having the respective concentrations of 0.1, 0.2, 0.5, 1.0, 2.0, 3.0, and 4.0 M. Quadruplicate reference standards of each element were prepared. Distribution coefficients of the elements on each resin were determined as described by Strelow (Strelow F. W., Distribution coefficients and ion exchange behaviour of some chloride complex forming elements with Bio Rad AG50W - X8 cation exchange resin in mixed Nitric-Hydrochloric acid solutions, 1989). From the distribution coefficients, obtained from the ICP-OES data, a selectivity series for the 14 elements, mentioned above, was arranged in the decreasing order for each resin’s affinity for the elements. The distribution coefficients also give an indication whether the elements can be quantitatively separated by the cation exchangers in nitric acid media. Elution curves for some elements were done to establish the experimental conditions for quantitative separations of the elements by column cation exchange chromatography.
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Мальований, А. М. "Екологічно безпечні технологічні процеси іонообмінно-біологічного очищення стічних вод від амонійного азоту." Thesis, Івано-Франківський національний технічний університет нафти і газу, 2013. http://elar.nung.edu.ua/handle/123456789/4632.
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Дисертація присвячена підвищенню рівня екологічної безпеки шляхом впровадження енергоефективної технології очищення стічних вод від амонійного азоту за умови сумісного застосування іонообмінних та біологічних процесів. Теоретично та експериментально досліджено обмінну ємність та селективність різних іонообмінних матеріалів (катіоніту КУ-2-8, катіоніт Purolite СІ04, природних та штучних цеолітів) у відношенні до іону амонію в процесах очищення стоків різного складу. Вивчено вплив складу регенераційного розчину на ефективність регенерації іонообмінних матеріалів. Досліджено вплив температури, концентрацій субстрату та NaCl у стічних водах на активність біологічного процесу Anammox. Проведений комплекс досліджень з метою адаптації аеробних та анаеробних бактерій-окисників амонію до підвищеного солевмісту та перевірки можливості очищення регенерату іонного обміну з використанням біологічного процесу часткової нітритації/Anammox. Результати роботи біологічних реакторів, що працювали за різних стратегій регулювання солевмісту, показали, що підвищення солевмісту вихідних стоків на 2,5 г/дм3 кожні два тижні є кращою стратегією і вона є прийнятною для адаптації культури бактерій аеробних та анаеробних окисників амонію. В результаті аналізу даних досліджень розроблені технічні рішення зі забезпечення екологічної безпеки на основі технологічних схем очищення міських стоків із вилученням амонію за двостадійною технологією.Диссертация посвящена повышению уровня экологической безопасности путем внедрения энергоэффективной технологи очистки сточных вод от аммонийного азота при условии совместного применения ионообменных и биологических процессов. Теоретически и экспериментально исследовано обменную емкость и селективность различных ионообменных материалов (катионита КУ-2-8, катионита Purolite С104, природных и искусственных цеолитов) по отношению к иону аммония в процессах очистки стоков различного состава. В результате исследования различных ионообменных материалов установлено, что максимальная емкость насыщения ионообменных материалов аммонием достигается для катионита КУ-2-8, природный и синтетический цеолит имеют более низкую, практически одинаковую емкость, емкость слабокислотного катионита Purolite С104 незначительная. Максимальная концентрация аммония в регенерате наблюдается для катионита КУ-2-8, а минимальная - для природного цеолита. Изучено влияние состава регенерационного раствора на эффективность регенерации ионообменных материалов. Установлено, что максимальная концентрация NaCl в регенерационном растворе позволяет достичь максимальной концентрации аммония в регенерате, однако даже при использовании раствора NaCl концентрацией 10 г/дм3 достигается необходимый степень концентрирования. В связи с этим в случаи использования неадаптированной культуры бактерий целесообразно использовать регенерационный раствор с концентрацией NaCl 10 г/дм3. Исследовано влияние температуры, концентраций субстрата и NaCl в сточных водах на активность биологического процесса Anammox. Проведен комплекс исследований с целью адаптации аэробных и анаэробных бактерий -окислителей аммония к повышенному солесодержанию и проверки возможности очистки регенерата ионного обмела с использованием биологического процесса частичной нитритации/Anammox. Результаты работы биологических реакторов, которые работали по различным стратегиям регулировки солесо-держания, показали, что повышение солесодержания выходных стоков на 2,5 г/дм3 каждые 2 недели является лучшей стратегией. Эта стратегия приемлема для адаптации культуры бактерий аэробных и анаэробных окислителей аммония. В результате анализа данных исследований разработаны технические решения по обеспечению экологической безопасности в условиях загрязнения гидросферы ионами аммония путем применения комбинирования ионообменных процессов с биологическими процессами частичной нитритации и процесса Anammox. Реализация этих решений позволяет повысить эффективность очистки сточных вод от азотосодержащих соединений с 40%, которая достигается в применяемых в Украине аэробных системах очистки стоков, до 87%. В сравнении с очисткой сточных вод от азотосодержащих соединений методами нитрификации и денитрификации, разработанная технология разрешает уменьшить количество активного ила, который образуется вследствие прохождения биологических процессов преобразования азота, в 10,4 раза, уменьшить на 216 грн расходы на очистку каждой тысячи м3 стоков.
The scope of the thesis is increase of environmental safety by implementation of energy efficient technology of ammonium removal from wastewater which includes combined application of ion exchange and biological processes. In this study exchange capacity and selectivity of different ion exchange materials (cation exchange resins KU-2-8 and Purolite Cl04, natural and synthetic zeolites) for ammonium ion was studied theoretically and experimentally using wastewaters of different content. Influence of regenerant content on effectiveness of ion exchange materials regeneration was established. Impact of temperature, substrate concentration and NaCl content on activity of Anammox bacteria was determined. Complex of experiments was carried out with an aim of aerobic and anaerobic ammonium oxidation bacteria adaptation to increased salinity and testing possibility of ion exchange regenerate treatment with partial nitritation/Anammox process. Performance of biological reactors which were operated with different strategies of salinity change showed that increase of salinity by 2.5 g/dm3 every two weeks is a strategy that allows adapting bacteria culture of aerobic and anaerobic ammonium oxidizers. By analyzing research outcomes, technical solutions for improving environmental safety were developed, which are based on technological schemes of municipal wastewater treatment with two-step technology of ammonium removal.
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Fernando, Kapila Chemical Sciences & Engineering Faculty of Engineering UNSW. "The treatment of cyanidation tailings using ion exchange resin." Awarded by:University of New South Wales. Chemical Sciences & Engineering, 2007. http://handle.unsw.edu.au/1959.4/40697.
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This thesis explores the behaviour of metal cyanide complexes under oxidative acid conditions in ion exchange systems, with the objective of developing an ion exchange based process for the treatment of gold cyanidation tailings. The novel cyanide detoxification process developed from this study employs strong base ion exchange resins to extract cyanide from tailings. Variations in the stability of cyanide complexes are exploited to concentrate, recover, or destroy cyanide species loaded on the resin, through the use of an oxidative acid eluent containing H2O2 and H2SO4. This eluent removes all base metal cyanide complexes from strong base resins, while regenerating the resin. The spent eluent, containing the base metals recovered from the tailings, can be used as a source of such base metals. Copper can be recovered separately from other base metals if necessary. Low levels of precious metals present in the tailings are accumulated on the resin as the ion exchange bed is cycled between loading and elution stages. They can be recovered economically, so as to offset the cost of the tailings detoxification. Cyanide is initially concentrated as an alkaline solution, which can be detoxified within the process or recovered for recycling. This process was successfully tested at pilot scale by treating approximately 14,000 m3 of cyanide contaminated tailings solution, over 14 loading/elution cycles on a standard strong base ion exchange resin bed. This treatment reduced the total cyanide concentration of the contaminated solution from approximately 50 mg/L to an average of 1.5 mg/L. The reagent cost was approximately ADD 0.50 per m3 of treated liquor. When the resin was repeatedly loaded with mixed metal cyanide species and eluted with the oxidative acid eluent, a gradual deterioration of the ion exchange resin performance was noted. The reduction of net operating capacity of the columns due to resin deterioration was in the order of 1-3% per loading/elution cycle. The oxidation of resin catalysed by copper, the precipitation of metal hexacyanoferrates on the resin and the oxidation of Au(CN)2- to Au(CN)4- were identified as possible factors giving rise to the reduction of resin loading capacity.
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Bábík, Pavel. "Výměny náboje mezi projektilem a terčem v režimu nízkých energií studované pomocí HS-LEIS." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382240.
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This diploma thesis is focused on the charge exchange processes between projectile and target studied by the Low Energy Ion Scattering (LEIS) technique. Basic premise to investigate charge exchange processes is correct cleaning processes and proper settings of experimental instrument Qtac 100 placed in the Central European Institute of Technology (CEITEC) in Brno. Ion fraction expresses neutralization rate of the projectile. The parametr is investigated for clean and oxidized polycrystalline copper. Oxygen presence performs a significant part of reionization of backscattered neutralized projectiles.
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Borghi, Andrea. "Cellulose hollow fibers membranes for ion-exchange chromatography." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20289/.
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The development of an efficient and cost-effective purification process is the objective of protein separation. Usually, the most common procedure is chromatography, typically performed in a packed bed column; however, the cost is relatively high.
Nowadays, one of the most interesting and promising method is the employment of particular membranes, the hollow fibers, in the standard chromatographic operations. Hollow fibers membranes were developed in the 1960s, specifically for reverse osmosis; nonetheless, they are now largely applied in both liquid and gaseous applications.
In this project, the preparation of cellulose hollow fibers, exploited for ion-exchange chromatography, was studied during a five months internship at the King Abdullah University of Science and Technology (KAUST) in the group of Professor Suzana Nunes.
The hollow fibers were prepared, dissolving cellulose in 1-Ethyl-3-methylimidazolium diethyl phosphate (EMIM DEP), an ionic liquid commonly used as green solvent for cellulose.
After a first research, regarding the performance of flat sheet membrane obtained by phase inversion, in which permeance and rejection were investigated using bovine serum albumin (BSA), the second phase of the project was the optimization of cellulose hollow fibers. Steps of the procedure included: a prior functionalization and application in ion-exchange chromatography. Ion exchange hollow fibers were, indeed, prepared reacting the cellulose with 1,4-butane sultone, and checked for proper functionalization by FTIR.
The ion-exchange fibers were primarily characterized in bind and elute mode using pure lysozyme solutions. The Tris buffer, chosen for equilibration and adsorption, was optimized in terms of molarity and pH.
The values of static binding capacity resulted in promising and comparable to that of the commercial ion-exchange membrane.
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Kerfai, Syrine. "Etude d'un procédé chromatographique d'échange d'ions pour la séparation de la ribulose 1,5-diphosphate carboxylase (Rubisco) dans le cadre de la valorisation d'un sous produit agricole." Thesis, Toulouse, INSA, 2011. http://www.theses.fr/2011ISAT0014/document.
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Les milieux biologiques bruts, provenant des opérations de transformation de biomasse sont souvent caractérisés à la fois par leur caractère polluant et par un potentiel de valorisation important. Le développement de procédés adaptés au traitement de tels milieux complexes présente ainsi beaucoup d’intérêt. Les jus verts générés par la déshydratation de la luzerne (Medicago Sativa) sont caractérisés par une forte teneur en protéines. Outre leur valeur nutritionnelle importante, ces protéines ont des applications potentielles dans plusieurs domaines, notamment environnemental de part leur teneur élevée en Ribulose 1,5 Bisphosphate Carboxylase Oxydase (Rubisco), enzyme responsable de la fixation du CO2 chez les plantes. Dans ce travail la séparation sélective de la Rubisco à partir du jus de luzerne industriel centrifugé par chromatographie d’échange d’ions a été étudiée. Dans un premier temps une méthode d’analyse qualitative et quantitative a été mise au point pour la détection et la quantification de la Rubisco en solution et ainsi le suivi du procédé de séparation. Dans un deuxième temps, le procédé de séparation a été étudié en colonne, en lit fixe et en lit expansé, en utilisant le support échangeur d’anions Q Hyper Z et l’effet de la dilution du milieu sur la capacité dynamique du procédé a été analysé dans les deux cas. Les résultats obtenus ont montré que les deux modes de contact permettent d’avoir des capacités dynamiques de rétention du même ordre de grandeur que celles de la littérature. Après élution, la Rubisco a été concentrée jusqu’à 21 fois et les fractions produites étaient caractérisées par un grand degré de pureté. Par ailleurs, des études d’équilibre et cinétique d’échange ont été initiées dans ce travail et ont démontré que malgré la taille importante de la protéine d’intérêt (560 kDa) les limitations stériques à son transfert ne sont pas plus importantes que dans le cas de protéines plus simples et plus petites et que le support Q Hyper Z présente effectivement une grande affinité pour la protéine. Enfin une première approche théorique a été conduite pour la compréhension des interactions entre la protéine et l’échangeur dans ce milieu complexe. Elle a permis de confirmer l’importance de la prise en compte de la présence d’autres biomolécules dans le milieu sur la rétention de la Rubisco, peut être même plus que celle des selsBiological raw material derived from bio-refinery processes, is often considered a source of pollution but it seems also to be a promising alternative to potential material recovery. The development of suitable processes for handling such complex biological material has so many concerns. Green juice produced from mechanical dehydration of Alfalfa (Medicago sativa) is an excellent source of protein with high nutritional quality. Ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) is the most abundant protein in the green juice, with potential applications in many fields, such as human nutrition, pharmaceuticals, environmental… The aim of this study is to isolate and recover Rubisco produced from an industrial alfalfa green juice, by ion exchange chromatography process. First of all, a qualitative and quantitative analytical method was developed to provide reliable information about Rubisco content monitoring in the separation process. In a second step, the separation process was performed in fixed and expanded bed, using the anion exchanger Q Hyper Z. In both cases, the effect of the dilution of the green juice on the dynamic capacity of the columns was studied. The results showed that the dynamic capacity retention was similar in both columns to those reported in literature. After elution step, Rubisco was concentrated 21 times and produced with high level of purity. Furthermore, kinetic of ion exchange study was initiated. Despite the large size of the protein (560 kDa), steric limitations to mass transfer were not very significant when compared to those of conventional small proteins. The support Q Hyper Z showed an excellent affinity for the protein recovery. Finally, a first theoretical investigation has been conducted for understanding the retention mechanism between the protein and the separation column. This study shows the importance of taking into account the presence of other bio-molecules in order to perform the retention of Rubisco, perhaps even more than that of salts
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Bood, Cecilia. "Acid retardation : recovery and recycling of acid and metal." Thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-78875.
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During the production of steel, an oxide scale is formed on the surface and to achieve anadequate quality of the surface the scale needs to be removed. Acid pickling is a surfacetreatment where the oxide scale is removed by acid. Over time the amount of dissolved metals in the acid solution increases leading to a decrease in the pickling efficiency, hence the acid solution needs to be renewed. The renewing can be performed by an operation process called acid retardation. In this process, the spent pickling solution passes through a column packed with an ion exchange material, resin. The absorption of strong acids is preferred by the resin, hence the movement of the acids in the resin bed will be retarded relative to the movement of the metal ions. Regeneration of the resin occurs when water is passing through the resin bed counter current to the flow of the spent pickling solution. This generates a by-product with low acid and high metal content, and a product containing high acid and low metal. The aim of this thesis was to investigate the acid retardation with regards to separation efficiency and the behaviour of acid and metal in the column. The results can further be used as the groundwork for a deeper understanding of the acid retardation and how to optimize the process. Experiments were performed in lab-scale columns with synthetic spent pickling solutions containing sulfuric, nitric and hydrofluoric acid and iron in different mixtures. During the experimental work, variation of the acid and metal concentration, the type of resin and the height of the column were performed. The results from the experimental work show that a concentration dependence between the concentration of acid and metal exists and the performance of different resin types varies depending on the acid and metal solution tested. The height might also affect the separation, but it is recommended that this is further investigated. Other recommendations for further work with a focus on understanding the acid retardation for optimization include variations of the volume of solution added to the column, variation in flow rate and slurry packing of the resin.
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Omoniyi, Emmanuel Oluseyi. "Comparative study of brine treatment using a functionalized nanofibre and an ion exchange resin." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2334.
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Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2015.In this study, comparative sorption studies of the major metal ions (Mg2+, Ca2+, K+ and Na+) in the brine wastewater were performed on hydrophilic materials (PAN nanofibre, PAN+TiO2 nanofibre, PAN+ZEOLITE nanofibre) and Purolite S950 resin to investigate their uptake performances. For this purpose, PAN nanofibre was electrospun and subsequently doped with 3 wt% each of titanium dioxide and zeolite respectively, in controlled experimental conditions in order to improve its performance. This was followed by the characterization of the respective hydrophilic materials (PAN, PAN+TiO2 and PAN+ZEOLITE nanofibres) using Fourier Transform Infrared Spectroscopy (FT-IR); Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). SEM showed that the incorporation of titanium dioxide or zeolite into the PAN structure made the surface rougher than that of the ordinary PAN nanofibre and FT-IR revealed the peaks belonging to titanium dioxide and zeolite respectively, showing the inorganic materials are within the PAN structure. The XRD analysis complemented the FT-IR of the nanofibres by revealing the peaks characteristic of titanium dioxide and zeolite are present on the PAN structure.
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Telesca, Francesco. "Experimental study of kinetics of cross-over in ion exchange membranes." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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Oggi, stiamo assistendo e allo sviluppo di tecnologie, che impiegano fonti di energia rinnovabile.
L’aumento della capacità produttiva da parte di queste fonti presenta però problematiche di natura tecnica.
Queste fonti energetiche sono si sostenibili, ma caratterizzate da scarsa costanza e prevedibilità.
Di conseguenza, lo studio di sistemi di accumulo dell’energia elettrica risulta di fondamentale importanza, in quanto tali sistemi di accumulo sono efficaci per gestire i problemi legati alla variabilità della produzione energetica.
Tra le tecnologie energetiche pulite, quelle elettrochimiche sono considerate le più praticabili, ecologiche e sostenibili.
Attualmente i più importanti sistemi di accumulo elettrochimico dell’energia elettrica sono rappresentati da Secondaries Batteries, Fuel Cells e Redox Flow Batteries.
Queste ultime, sono tra le più promettenti per questo tipo di applicazioni, in quanto sono caratterizzate dal fatto che energia e potenza sono disaccoppiati poichè i reattivi sono immagazzinati all’esterno del “reattore”.
Nelle batterie redox a flusso i reattivi, costituiti da coppie redox in soluzione acquosa, sono fatti circolare da pompe in un elettrolizzatore costituito da elettrochimiche in serie dove i compartimenti anodico e catodico sono separati da membrane a conduzione cationica o anionica che impediscono il contatto diretto dei reattivi.
Questo lavoro di tesi ha come obiettivo lo studio degli aspetti principali di questi sistemi.
Nella prima parte della sperimentazione sono stati condotti degli esperimenti per la caratterizzazione morfologica delle membrane.
Successivamente è stata definita una metodologia per il calcolo del coefficiente di cross-over di questi processi e i risultati preliminari di caratterizzazione sono stati utilizzati per definire le condizioni operative per cui tale metologia è valida.
Infine è stato fatto un cofronto fra i risultati di cross-over ottenuti per membrane con differente morfologia.
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Drew, Margaret Jane. "Optimisation of the Ion exchange juice treatment plant at Ashton Cellars." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52389.
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Thesis (MScEng)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: Recently concern has been raised regarding effluent from wine cellars, as it often does not comply with environmental legislation. It was with this in mind that the effluent problem at Ashton Cellars was addressed. After carrying out a water audit of the plant, described in Chapter 3, it was concluded that the ion exchange plant is a significant contributor to the low pH and high conductivity of the effluent dam. Decreasing the effluent from the ion exchange plant should therefore help in improving the total effluent quality. During the water audit opportunities to improve the effluent by making small process changes in the cellar were identified. The primary objective of this study was to provide guidelines to improve the quality and decrease the volume of the effluent from the ion-exchange plant to more environmentally acceptable levels, whilst maintaining product specifications and production rates. This was achieved by studying the operation of the plant (Chapter 4) and testing the characteristics of the current and alternative resins (Chapter 5). Auditing of the ion exchanges plant included a detailed analysis of the regeneration and loading of the ion exchange columns. It was concluded that the operation of the plant can only be optimised once pH and/or conductivity meters, and preferably an automated control system, are installed on the plant. The results given in this thesis can be used as a guide when setting up such a control system. Laboratory testing of the resins revealed that the cation resin currently being used on the plant has been fouled and loads at a slow rate. When the resins are replaced, the use of Purolite CISO and Purolite A103S should be considered as these resins gave the most favourable results. Some alternative treatment methods for the processing of grape must, have been mentioned in Chapter 6.
AFRIKAANSE OPSOMMING: Al meer kornrner word deesdae uitgespreek oor wynkelders se afvalwater, omdat dit meerendeels nie aan die vereistes van omgewingswetgewing voldoen nie. Dit was met hierdie probleem in die oog dat die afvalwater probleem by Ashton Kelders ondersoek IS. Nadat 'n wateroudit van die fabriek, soos beskryf in Hoofstuk 3, uitgevoer is, is daar tot die slotsom gekom dat die ioonuitruilsisteem 'n groot bydra tot die lae pH en hoe konduktiwiteit van die afvaldam lewer. Indien die ioonuitruilsisteem se uitvloeisel verminder kon word, sou dit tot 'n groot mate bydrae tot 'n verbetering van die totale uitvloei kwaliteit. Gedurende die wateroudit is verskeie moontlikhede vir die verbetering van die uitvloei deur klein prosesveranderinge aan te bring, geidentifiseer. Hierdie studie het as hoof oogmerk die daarstelling van riglyne vir die verbetering van die kwaliteit en grote van die afvalstrome van die ioonuitruilsisteem om sodeende aan omgewingswetgewing te voldoen, maar ter selfder tyd die produk spesifikasies en tempos te handhaaf. Dit is gedoen deur die huidige bedryf van die fabriek te bestudeer (Hoofstuk 4) en die eienskappe van die huidige en altematiewe ioonuitruilharse te toets (Hoofstuk 5). Die oudit van die ioonuitruilsisteem het 'n gedetaileerde anaIiese van die hergenerasie en lading van die ioonuitruilkolornrne ingesluit. Daar is tot die slotsom gekom dat die bedryf van die sisteem alleenlik geoptirniseer kon word indien pH en/of konduktiwiteitsmeters, en verkieslik 'n automatiese kontrolesisteem geinstalleer word. Die resultate van hierdie tesis kan as basis vir so 'n kontrole sisteem gebruik word. Die laboratoriumtoetse op die harse het aan die lig gebring dat die katioonhars wat tans in gebruik is, baie vervuil is en net teen 'n lae tempo belaai kan word. Wanneer die harse vervang word, word die gebruik van Purolite el50 en Purolite A103S aangeraai, aangesien hierdie harse die beste resultate gelewer het. Altematiewe behandelingsmetodes van druifmos is in Hoofstuk 6 genoem.
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Ament, Felix. "Energy and moisture exchange processes over heterogeneous land surfaces in a weather prediction model." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980850878.
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Iglesias, Juncà Mònica. "Utilització de suports polimèrics en processos de separació de metalls valuosos. Aplicacions hidrometal.lúrgiques i analítiques." Doctoral thesis, Universitat de Girona, 2000. http://hdl.handle.net/10803/96340.
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The present study focuses on the characterization of solid-liquid extraction techniques for the separation and preconcentration of rare-earth elements and precious metals. We developed an impregnated resin with di (2-ethylhexyl)phosphoric acid (D2EHPA) in order to separate rare-earth elementsEls treballs realitzats es centren en la caracterització de sistemes d’extracció sòlid-líquid per a la separació i preconcentració de terres rares i metalls preciosos. Amb aquest objectiu es varen avaluar diferents resines quelants, majoritàriament disponibles comercialment, per a la separació i recuperació de metalls preciosos, així com la seva aplicació a processos en columna utilitzant llits de resina fixos. També s’inclou la caracterització del procés de separació d’itri i neodimi mitjançant una resina impregnada amb dissolvent
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Riani, Josiane Costa. "Utilização de resinas de troca-iônica em efluentes de galvanoplastia." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-30092008-151250/.
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A crescente industrialização acompanhada do uso de metais pesados nos processos industriais nas últimas décadas resultou num aumento da contaminação do meio ambiente, principalmente em ambientes aquáticos. Assim, sendo a água um recurso natural de suma importância para a vida, métodos de tratamento de efluentes tornam-se indispensáveis para empresas geradoras de efluentes. O objetivo desse trabalho é a utilização de um sistema de troca iônica constituído por micro-colunas de resinas catiônicas e aniônicas para adsorção de metais pesados de soluções industriais, visando à recirculação de água de lavagem de processos de galvanoplastias. As resinas utilizadas são: Amberlyst 15 WET e Amberlyst A-21; Dowex Marathon C e Dowex Marathon A; Purolite C-150 e Purolite A-850. Também se avalia a eluição dos íons metálicos nas resinas em questão. O efeito que a temperatura possui na eluição é avaliado para as resinas catiônicas, Purolite C-150 e Dowex Marathon C. A cinética e a termodinâmica de adsorção do cromo trivalente e do zinco são avaliados. A metodologia consiste em realizar experimentos de adsorção e eluição em colunas de troca-iônica e experimentos de adsorção em batelada para análise da cinética e termodinâmica dos íons presentes em solução. Os resultados mostram que a qualidade da água após a adsorção nos três sistemas propostos está de acordo com os valores permitidos pela Resolução CONAMA 357/05. Analisando os resultados da eluição nas resinas se verifica que o aumento da temperatura favorece a remoção de íons presentes nos sítios de troca da resina, com exceção do cromo trivalente. As reações de troca-iônica dos íons Cr3+ e Zn2+ seguem os modelos de reação pseudo-segunda ordem. A natureza das reações de troca-iônica do cromo trivalente nas resinas estudadas é exotérmica e a do zinco é endotérmica.The increasing industrialization carried out with the use of heavy metal in industrial processes over the last decades resulted in increasing environmental contamination, mainly in aquatic environments. Thus, as water is an extremely important natural resource for life, effluent treatment methods become essential for effluent generating companies. This work aims at using an ionic exchange system made of micro-columns of both cathionic and anionic resins for heavy metals adsorption of industrial solutions, for the recirculation of wastewater from electroplating processes. The resins used are: Amberlyst 15 WET and Amberlyst A- 21; Dowex Marathon C and Dowex Marathon A; Purolite C-150 and Purolite A-850. An evaluation of the metallic ions elution is also carried out for such resins. The effect of temperature on the elution is assessed for cathionic resins, Purolite C-150 and Dowex Marathon C. The adsorption kinetics and thermodynamics for trivalent chrome and zinc are assessed. The methodology consists of carrying out experiments of adsorption and elution in ion exchange columns and experiments of adsorption by batch for both kinetic and thermodynamic analyses of ions present in the solution. The results show that the water quality after the adsorption in all three systems proposed is in accordance with the values allowed by the CONAMA 357/05 Resolution. By analyzing the results of the elution in the resins, one can observe that the temperature increase favors the removal of ions present in resin-exchange sites, except for the trivalent chrome. The reactions of ionic exchange of Cr3+ and Zn2+ ions follow the models of pseudo-second order reaction. For the resins analyzed, the nature of ionic exchange reactions of the trivalent chrome is exothermic and of the zinc is endothermic.
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Fields, Marilyn A. "Development of nitroguanidine wastewater treatment technologies." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/74516.
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Nitroguanidine (NQ) is a nitramine used in many propellant formulations. The purpose of this study was to develop a method for treating nitroguanidine process wastewaters. The major wastewater contaminants were found to be nitroguanidine and guanidine nitrate (GN) (an intermediate product). Pilot tests were conducted for the removal of nitroguanidine using granulated carbon adsorption (GAC) and ion exchange for the removal of GN. The nitroguanidine concentration in demonstration plant wastewater was reduced from 15.5 mg/L to less than 1 mg/L. The carbon capacity was found to be 0.045 g NQ/g carbon. Strong acid resin was found to reduce guanidinium ion Gu⁺ concentration from 14.5 mg/L to 1 mg/L with a resin capacity of 0.13 eq Gu⁺ /L resin. No significant reduction in resin capacity for Gu⁺ was experienced after five regenerant cycles. A unique two-step regeneration was used. This included a 5% calcium nitrate solution to produce a spent regenerant that could be recycled to the production process. This was followed by regeneration with a 15% sodium chloride solution to place the resin in the sodium form. Anion exchange was used for the removal of nitrate ions.Master of Science
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Fonseca, Christiane Reis. "Uso combinado de processos de separação visando a destoxificação de hidrolisado hemicelulósico." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/97/97137/tde-26092012-154852/.
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A presença de compostos inibidores ao metabolismo de microrganismos é a principal dificuldade encontrada para utilização dos hidrolisados hemicelulósicos para produção de etanol e xilitol. Compostos derivados das degradações da lignina, da celulose e hemicelulose são liberados durante a hidrólise ácida da biomassa. O presente trabalho teve como objetivo avaliar a utilização de diferentes tratamentos de destoxificação de forma combinada, visando a purificação do hidrolisado hemicelulósico de bagaço de cana-de-açúcar para obtenção de etanol e xilitol. Os tratamentos utilizados foram: coagulação/floculação de impurezas coloidais, separação por membranas de microfiltração e ultrafiltração e resinas de troca iônica, sendo o material de partida foi um hidrolisado de bagaço recém-obtido. O tratamento de coagulação/floculação foi otimizado utilizando planejamento de experimentos do tipo fatorial e na melhor condição promoveu reduções de 53,3% em compostos fenólicos, 34,8% de furfural, 3,7% de HMF, 4,2% de ácido acético e 67,6% da área espectral. Na sequência, o hidrolisado tratado na etapa anterior foi submetido a testes de microfiltração e ultrafiltração. Para esta etapa os melhores resultados foram obtidos utilizando membranas de 100 kDa em polietersulfona. Com este tratamento foi possível reduzir em 11,9% os compostos fenólicos, 23,8% de furfural, 21,5% de HMF e 21,4% de área espectral. Após o tratamento com membranas o hidrolisado foi percolado em resinas de caráter catiônico e aniônico utilizadas em série possibilitando a eliminação de 34,8% de compostos fenólicos, 38,5% de furfural, 74,7% de HMF, 55% de ácido acético e 10,3% da área espectral. Ao final, a combinação de todas as tecnologias de separação estudadas possibilitou remoções maiores que 97% para compostos fenólicos, furfural e HMF o que resultou numa redução da área espectral em 99,3%. O hidrolisado purificado foi concentrado e submetido a testes fermentativos preliminares para produção de etanol e xilitol. Estas bioconversões apresentaram rendimentos de 0,58 g/g em xilitol e 0,29 g/g em etanol por D-xilose consumida, que equivalem a 86% e 83% dos rendimentos obtidos a partir dos meios sintéticos, respectivamente. Estes resultados indicaram que a purificação obtida através do uso combinado da coagulação/floculação, separação por membranas e resinas de troca iônica foram bastante satisfatórios principalmente considerando a fermentabilidade obtida a partir deste substrato em comparação ao meio sintético.The presence of inhibitory compounds in the metabolism of microorganisms is the main difficulty for the use of hemicellulosic hydrolyzate for ethanol and xylitol production. Compounds derived from lignin, cellulose and hemicellulose degradation are released during the biomass acid hydrolysis. This study aimed to evaluate the use of different detoxification treatments in combination, aimed at purifying the hydrolyzed hemicellulosic sugarcane bagasse. The treatments were: coagulation / flocculation of colloidal impurities, separation by microfiltration and ultrafiltration membrane and ion exchange resins, and the starting material was a newly obtained hydrolyzed bagasse. The treatment of coagulation / flocculation was optimized using factorial experiments design of the kind that in the best condition promoted reductions of 53.3%, 34.8%, 3.7%, 4.2% and 67.6% in phenolic compounds, furfural, hydroxymethylfurfural, acid acetic acid and spectral area, respectively. Next, the hydrolyzate treated in the previous step was tested for microfiltration and ultrafiltration. For this step the best results were obtained using a 100 kDa membrane in polyethersulfone. With this treatment were obtaneid reduction of 11.9%, 23.8%, 21.5%, 21.4% in phenolic compunds, furfural, hydroxymethylfurfural and spectral area, respectively. After membrane treatment the hydrolyzate was percolated through resins with anionic and cationic character used in series enabling the elimination of 34.8%, 38.5%, 74.7%, 55% and 10.3% of phenolic compounds, furfural, hydroxymethylfurfural, acetic acid and spectral area, respectively. At the end, the combination of all separation technologies studied was able to remove greater than 97% of phenolic compounds, furfural and hydroxymethylfurfural which resulted in a reduction of 99.3% in spectral area. The purified hydrolyzate was concentrated and subjected to preliminary fermentative testing for the ethanol and xylitol production. These bioconversions had income of 0.58 g/g in xylitol and 0.29 g/g in ethanol by D-xylose consumed, equivalent to 86% and 83% of ethanol and xylitol yield obtained from the synthetic medium, respectively. These results indicated that the purification achieved through the combined use of coagulation/flocculation, membrane separation and íon exchange resins were very satisfactory, especially considering the fermentability obtained from this substrate compared to the synthetic medium.
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Gaillard, Jean-François. "Quelques processus geochimiques lies a la diagenese precoce." Paris 7, 1987. http://www.theses.fr/1987PA077205.
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On etudie la diagenese chimique dans les sediments lacustres et marins recents. L'analyse chimique des eaux interstitielles permet de dresser des bilans matieres et des bilans stoechiometriques rendant compte de l'ensemble des transformations diagenetiques, d'envisager la precipitation de mineraux authigenes, de quantifier les precipitations et dissolutions et d'estimer les flux de metaux trace a l'interface eau-sediment. On poursuit le travail par l'analyse des sediments et des interactions existant a la surface des particules. On presente un protocole experimental pour extraire selectivement les metaux traces des sediments et un modele de leur adsorption sur les surfaces des particules en suspension au-dessus du fond. On envisage enfin les phenomenes de diffusion et les mecanismes de transport ionique dans les eaux interstitielles
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Pierini, Giulia. "Preparation and characterization of grafted nonwoven membranes for bioseparations." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11903/.
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Protein purification plays a crucial role in biotechnology and biomanufacturing, where downstream unit operations account for 40%-80% of the overall costs. To overcome this issue, companies strive to simplify the separation process by reducing the number of steps and replacing expensive separation devices. In this context, commercially available polybutylene terephthalate (PBT) melt-blown nonwoven membranes have been developed as a novel disposable membrane chromatography support. The PBT nonwoven membrane is able to capture products and reduce contaminants by ion exchange chromatography. The PBT nonwoven membrane was modified by grafting a poly(glycidyl methacrylate) (GMA) layer by either photo-induced graft polymerization or heat induced graft polymerization. The epoxy groups of GMA monomer were subsequently converted into cation and anion exchangers by reaction with either sulfonic acid groups or diethylamine (DEA), respectively. Several parameters of the procedure were studied, especially the effect of (i) % weight gain and (ii) ligand density on the static protein binding capacity. Bovine Serum Albumin (BSA) and human Immunoglobulin G (hIgG) were utilized as model proteins in the anion and cation exchange studies. The performance of ion exchange PBT nonwovens by HIG was evaluated under flow conditions. The anion- and cation- exchange HIG PBT nonwovens were evaluated for their ability to selectively adsorb and elute BSA or hIgG from a mixture of proteins. Cation exchange nonwovens were not able to reach a good protein separation, whereas anion exchange HIG nonwovens were able to absorb and elute BSA with very high value of purity and yield, in only one step of purification.
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Grey, Catherine Vyvian. "Physiochemical Treatment Options for High-Conductivity Coal Mining Runoff." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/85011.
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In recent years, the excessive specific conductance (SC) of Appalachian coal mining runoff waters has become a parameter of concern with the EPA due to its negative effect on aquatic life and water quality. In order to comply with the EPA guidance suggesting an effluent SC of 500 µS/cm, the Appalachian Research Initiative for Environmental Science (ARIES) Center at Virginia Tech requested that testing be done to determine the most effective technologies for reduction of SC. Runoff water was collected from two sites in southwestern Virginia and characterized to determine the source of SC in the water. The main contributing ions were determined to be Na⁺, Mg²⁻, Ca²⁺, and SO₄²⁻. Testing was performed to assess the possibility of using the speciation software, MINEQL+, with a set of empirical equations which predict SC using ionic composition for natural waters with a low to medium SC.
The physicochemical treatment methods tested were ion exchange, excess lime-soda softening, and the Cost Effective Sulfate Removal (CESR) process. Both cation (H⁺ exchanger) and anion (Cl⁻ exchanger) exchange media were tested separately in batch reactors, which resulted in a higher effluent SC than initial SC. The softening method investigated, excess lime-soda softening, also resulted in increased SC levels because non-carbonate hardness levels were high and carbonate concentrations were low. The CESR process successfully lowered SC from 1,500-2,500 µS/cm to below the proposed EPA limit of 500 µS/cm. The success of this process was due to its ability to remove more than 85% of the calcium, magnesium, and sulfate from the water, which together accounted for more than 90% of ions in the source water.Master of Science
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Alharati, Assma Ahmed. "Élimination du bore contenu dans l’eau de mer par un système hybride de sorption par résines échangeuses d’ions et de microfiltration." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1051/document.
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Le dessalement de l’eau de mer par osmose inverse connait un intérêt croissant depuis une vingtaine d’années afin de répondre aux besoins en eau potable et en eau d’irrigation dans de nombreuses régions dans le monde. Cependant, le bore contenu dans l’eau de mer est incomplètement éliminé par osmose inverse et des concentrations supérieures à la valeur limite de 0,3 mg/ sont obtenues. Dans cette étude, nous présentons des résultats sur l'élimination du bore de l'eau de mer en utilisant une technique hybride de résine échangeuse d'ions/microfiltration sans addition continue de résine. Une membrane de microfiltration en céramique a été utilisée pour retenir la résine échangeuse d'ions dans le réservoir d'alimentation et la boucle de circulation tandis que la solution modèle de bore ou l’eau de mer était continuellement ajoutée. Tout d'abord, des résines fines de taille moyenne 40 - 60 µm ont été obtenues par broyage et tamisage de résines commerciales (Amberlite IRA743, Diaion CRB05 et Purolite S108). Les résines ont ensuite été testées en système batch pour obtenir les cinétiques de sorption et par la technique hybride de sorption/microfiltration pour mesurer les courbes de perçage et le flux de perméat. L'effet de la dose de résine, de la concentration initiale en bore, de la pression transmembranaire et de la taille des pores de la membrane a été étudié. Dans une deuxième partie, l’effet de la taille des particules de résine sur les courbes de perçage en sortie d’une colonne a été déterminé et une comparaison entre les performances d’une colonne et d’un système hybride a été proposée. Dans une dernière partie, les isothermes et cinétiques de sorption expérimentales sont comparées à des équations classiques, et les courbes de perçage en colonne et en système hybride sont modélisées. En conclusion, il est suggéré que le procédé hybride de résine échangeuse d'ions et microfiltration sans ajout continu de résines peut être une technique possible pour l'élimination du boreThe maximum concentration suggested by the World Health Organization is 0.3 mg/L. In this study, we investigated a hybrid process for boron removal from water which associates sorption on ion exchange resin and microfiltration, without continuous resin addition. First, fine resins were obtained by grounding and sieving at 40 and 60 µm commercial resins (Amberlite IRA743, Diaion CRB05 and Purolite S108). The resins were then tested in batch to obtain the kinetics and in the hybrid sorption/microfiltration process to measure breakthrough curves and permeate flux. A ceramic microfiltration membrane was used to retain the ion exchange resin in the feed tank and the circulation loop while the boron solution was continuously added and the permeate collected for analysis. The effect of resin dosage, boron initial concentration, transmembrane pressure and membrane pore size was studied. In a second part, the effect of the size of the resin particles on the breakthrough curves measured at the outlet of a column was determined and a comparison between the performances of a column and a hybrid system are proposed. For the Amberlite IRA743 resin, the overall process was tested: reverse osmosis followed by hybrid sorption/microfiltration. The hybrid process was able to re-duce concentration of bacterial and phytoplankton cells thanks to the steric rejection by the microfiltration membrane, suggesting that the same membrane can be used as a pretreatment before reverse osmosis in a desalination plant. In a final part, the experimental isotherms and kinetics are compared with classical models, and the breakthrough curves obtained with a column and with the hybrid sys-tem are modelised. Overall, it is suggested that the hybrid process of ion exchange resin and microfiltration without continuous addition of resin may be a possible technique for boron removal
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Hendricks, Nicolette Rebecca. "The application of high capacity ion exchange adsorbent material, synthesized from fly ash and acid mine drainage, for the removal of heavy and trace metal from secondary Co-disposal process waters." Thesis, University of the Western Cape, 2005. http://hdl.handle.net/11394/1455.
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In South Africa, being the second largest global coal exporter, coal mining plays a pivotal role in the growth of our economy, as well as supplying our nation’s ever increasing electricity needs; while also accounting for more than 10% of the 20 x 109 m3 water used annually in the country. Coal mining may thus be classified as a large-scale water user; known to inevitably generate wastewater [acid mine drainage (AMD)] and other waste material, including fly ash (FA). Current and conventional AMD treatment technologies include precipitation–aggregation (coagulation/flocculation) – settling as hydroxides or insoluble salts. The process stream resulting from these precipitation processes is still highly saline, therefore has to undergo secondary treatment. The best available desalination techniques include reverse osmosis (RO), electro dialysis (ED), ion exchange and evaporation. All available treatment methods associated with raw AMD and its derived process stream fall prey to numerous drawbacks. The result is that treatment is just as costly as the actual coal extraction. In addition, remediation only slows the problem down, while also having a short lifespan. Research conducted into converting fly ash, an otherwise waste material, into a marketable commodity has shown that direct mixing of known ratios of FA with AMD to a pre-determined pH, erves a dual purpose: the two wastes (AMD and FA) could be neutralized and produced a much cleaner water (secondary co-disposal [FA/AMD]-process water), broadly comparable to the process water derived from precipitation-aggregation treated AMD. The collected post process solid residues on the other hand, could be used for production of high capacity ion exchange material (e.g. zeolite A, faujasite, zeolite P, etc.). The produced ion exchange material can subsequently be utilized for the attenuation of metal species in neutralized FA/AMDprocess waters.Magister Scientiae - MSc
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Jaïdane, Nejmeddine. "Etude du transfert de charge entre des atomes de soufre et des protons." Paris 7, 1987. http://www.theses.fr/1987PA077121.
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Calculs scf et ci des courbes de potentiel du systeme s+h**(+) dans les symetriplets pi et delta internenant dans la reaction, avec des orbitales moleculaires occupees representees par des orbitales atomiques polarisees et des orbitales moleculaires virtuelles donnees par la projection d'orbitales atomiques orthogonalement aux orbitales occupees. Traitement de la dynamique de l'echange de charge dans une representation diabatique ou les couplages radiaux sont nuls et l'echange de charge est induit par des couplages de type electronique. Construction d'une representation effective de dimension reduite au nombre des voies ouvertes; calcul des couplages radiaux. Resolution des equations de collision par un traitement quantique dans chaque symetrie; deduction de la constante de vitesse
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Monaco, Enzo. "pH Transients in Hydroxyapatite chromatography columns." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Find full textAbstract:
Ceramic Hydroxyapatite (CHT), with empirical formula (Ca5(PO4)3OH)2, is a material used as ion exchange resin in chromatographic applications. The material, having both positive and negative charged sites, can be used in many different contexts encountered in the protein purification processes. Nevertheless, the resin shows an intrinsic limitation for this kind of applications: even if the material solubility in water is very low at pH values higher than 6.5, it sharply increases in more acidic environments, reducing the life of the material and increasing the operative costs of the process, making problematic the CHT application at these conditions.
There is a further complication related to the CHT application: it is experimentally reported that the result of the resin interactions with salts is a pH transient occurring in the liquid phase of the chromatographic column.
These pH variations are temporary but remarkable, they may influence in an important manner the material solubility, affecting the number of utilization cycle of the fixed bed and, eventually, the stability of the proteins involved in the separation process.
In this work the principal aspects contributing at the selection of the operating pH and of the buffering specie are analyzed, discussing also the effect of the buffer itself on the material solubility.
Then, it is reported a mathematical model useful for the description of the dynamic behavior of the column and it is proposed an interaction mechanism between the salts of the mobile phase and the stationary phase. In particular, it is emphasized the discussion regarding the different affinity shown by the stationary phase for the different counter-ions which may accompanies the buffering specie.
Finally, a series of equations are developed at the scope to obtain a model useful to describe the observed pH transients.
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Numbonui, Ghogomu Julius. "Transports facilités et actifs couplés à l'énergie thermique dans les systèmes membranaires non-isothermes. Applications à l'acide borique et au gaz carbonique." Rouen, 1993. http://www.theses.fr/1993ROUES058.
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Nous avons entrepris d'illustrer le transport-réaction non isotherme par des exemples étudiés précédemment au laboratoire en conditions isothermes : le transport facilité de l'acide borique par l'ion borate à travers une membrane échangeuse d'anions et le transport facilité du dioxyde de carbone par l'éthylènediamine monoprotonée à travers une membrane échangeuse de cations. Ces deux exemples mettent en jeu respectivement la formation des polyborates et d'un complexe carbamique dont les stabilités diminuent avec la température. L'étude expérimentale détaillée de ces deux systèmes est suivie d'une approche théorique utilisant des modèles de la littérature. Nous avons ainsi pu évaluer les coefficients phénoménologiques reliant le flux non-isotherme au gradient de potentiel chimique du perméant et au gradient de température. Nous avons aussi pu prévoir quantitativement les flux observés expérimentalement en étendant aux cas non-isothermes le modèle de transport-réaction développé jusqu'ici au laboratoire pour traiter du transport-réaction isotherme d'espèces neutres dans les membranes ioniques. Enfin les calculs et travaux préliminaires ouvrent la voie à des nouvelles investigations sur le transport actif thermique
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Hendricks, Nicolette Rebecca. "The application of high capacity ion exchange absorbent material, synthesized from fly ash and acid mine drainage, for the removal of heavy and trace metals from secondary co-disposed process waters." Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
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The objective of this study was to investigate the feasibility of the application of low cost high capacity inorganic ion exchange material, synthesized form collected fly ash and acid mine drainage solid residues, for the decontamination of secondary co-disposal process waters, with emphasis on investigating the processes governing the solid/solution interface.
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Souza, Jadison Fabricio de. "Desenvolvimento de membranas de polissulfona para imobilização de lipase." reponame:Repositório Institucional da UCS, 2006. https://repositorio.ucs.br/handle/11338/168.
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Este trabalho teve por objetivo a preparação e caracterização de membranas de polissulfona (PSU) e a imobilização da enzima lipase nestes filmes, para a produção de membranas enantiosseletivas, visando utilização futura em separação de misturas quirais. Membranas de PSU foram preparadas pelo processo de inversão de fase, utilizando clorofórmio como solvente e água como agente coagulante para a inversão. Foram preparadas membranas com diferentes espessuras e os seguintes parâmetros para a inversão de fase foram definidos: concentração das soluções, tempo de evaporação do solvente, secagem e tratamento térmico. As membranas foram caracterizadas, visando a utilização em processo de eletrodiálise (ED) e imobilização da enzima lipase PS. Para a imobilização foi utilizado o glutaraldeído como agente bifuncional para ligação da enzima ao polímero. Na imobilização foram determinados os parâmetros cinéticos velocidade máxima (Vmáx) e constante de Michaelis-Menten (Km), a quantidade de enzima imobilizada nas membranas pelo método de Bradford e a atividade da enzima livre e imobilizada através da hidrólise do acetato de p-nitrofenila (PNPA). As membranas de PSU preparadas por inversão são hidrofóbicas, e apresentaram características de permesseletividade e capacidade de troca iônica inferiores às apresentadas pelas membranas comerciais Selemion®; CMT e CMV e resistência elétrica superior à destas membranas. O diâmetro dos poros nas membranas é menor que 100 nm. . A quantidade máxima de enzima imobilizada foi de 2,35 mg .g-1 de polímero em 18 horas de imobilização com um rendimento de 61,2%. A atividade da enzima decai após a imobilização, de 14780 U.g-1 (enzima livre) para 1184 U.g-1 (enzima imobilizada).Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-13T17:21:10Z No. of bitstreams: 1 Dissertacao Jadison Fabricio de Souza.pdf: 3168334 bytes, checksum: ec62af877268ce2e7d357db5c8c5e372 (MD5)
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Preparation and characterization of polysulfone (PSU) membranes and the immobilization of lipase enzyme in these membranes to produce enantioselective membranes, in order to separate chiral compounds, is the subject of the present work. PSU membranes were prepared by phase inversion, using chloroform as solvent and water as nonsolvent. Membranes with different thickness were prepared and phase inversion parameters such as (solution concentrations, solvent evaporation time, drying and thermal treatment) were investigated. Membranes were characterized, in order to use them in electrodialysis process (ED) and in the lipase PS enzyme immobilization. For immobilization, bifunctional agent glutaraldehyde was used to link the enzyme to the polymer. On immobilization, the kinetic constants (Km e Vmax), the amount of immobilized enzyme with Bradford method and the activity of free and immobilized enzyme with p-nitrophenyl acetate (PNPA) hydrolysis, were determined. PSU membranes prepared by phase inversion are hydrophobic and, when compared with Selemion®; CMT and CMV commercial membranes, present lower permeselectivity, lower ion exchange capability and higher resistance. Membranes pore diameter is lower than 100 nm. The maximum amount of immobilized enzyme in the membranes reached 2.35 mg per gram of polymer after 18 hours of immobilization with a 61,2% yield . Enzyme activity decays after immobilization , from 14780 U.g-1 (free enzyme) to 1184 U.g-1 (immobilized enzyme).
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Caisso, Marie. "Etude structurale de la synthèse de microsphères d’U1-xAmxO2±δ dédiées à la fabrication de couvertures chargées en américium." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT204/document.
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Une des voies à l’étude permettant de réduire l’inventaire des déchets nucléaires, après recyclage du plutonium, est la transmutation hétérogène, en réacteurs à neutrons rapides, de l’américium (Am) en éléments chimiques à demi-vies courtes, voire stables. L’irradiation de l’Am nécessite la fabrication de pastilles d’U1-XAmXO2±δ. La voie CRMP (Calcined Resin Microsphere Pelletization) est actuellement privilégiée parmi les différents procédés envisagés. Elle se base, avant frittage, sur le pressage de microsphères d’oxyde mixte U1-XAmXO2±δ obtenues par conversion thermique de microsphères de résine échangeuse d’ions chargée en cations UO22+ et Am3+. Comparé à des voies de synthèse classique utilisant la métallurgie des poudres, le procédé CRMP permet de favoriser les étapes de mise en forme (forte coulabilité des microsphères) tout en limitant la dissémination de particules fines à base d’Am, hautement radioactives. Dans ce contexte, cette thèse s’attache à mener une caractérisation exhaustive des différentes étapes du procédé CRMP d’un point de vue mécanistique et structural. Ainsi, le mode de complexation des cations dans la résine a été déterminé, via la mise en évidence de groupements carboxyliques bidentés autour des éléments U et Am. L’étape de conversion thermique a également été suivie de manière in-situ, et les structures des différents composés oxydes formés, (U1-XAmX)3O8 et U1-XAmXO2±δ, ont été identifiées et caractérisées finement. La substitution de l’Am dans chacun des composés a été démontrée, ainsi que les déformations associées autour des cations. Finalement, le frittage des microsphères sous forme de pastilles d’U1-XAmXO2±δ a été caractérisé, révélant une densification en deux étapes. Ce comportement singulier est le résultat d’une réorganisation multi-échelle dans le matériau ayant lieu au cours du frittage, s’expliquant par la présence dans le cru de nanoparticules pré-frittant à basse températureOne of the studied routes to reduce nuclear waste amount, is, after plutonium recycling, americium (Am) heterogeneous transmutation in fast neutron reactors, through the generation of short-lives and inert elements. Am irradiation requires the fabrication of U1-xAmxO2±δ pellets and the CRMP (Calcined Resin Microsphere Pelletization) process is currently considered as one the most promising candidate among other fabrication routes. It is based, before pellet sintering, on the compaction of U1-XAmXO2±δ oxide microspheres, synthetized through the thermal conversion of ion exchange resin microspheres, loaded with UO22+ and Am3+ cations. Compared to standard methods using powder metallurgy, CRMP process favours pressing step (easy microsphere flow) while limiting generation of highly radioactive Am-based fine particles. In this context, this PhD work was focused on the exhaustive characterization of CRMP process different steps, from a mechanistic and structural point of view. The cation molecular complex used in the resin was thus determined, highlighting carboxylic bidendate ligand binding around U and Am elements. Thermal conversion was also in-situ followed, and the structures of the different synthetized compounds evidenced and accurately characterized, i.e. (U1-XAmX)3O8 et U1-XAmXO2±δ. Am substitution in each of them was explained, revealing related distortions around U and Am cations. Finally, sintering of U1-XAmXO2-δ microspheres shaped into pellets was studied, showing a two-step densification. This unusual behavior corresponds to multi-scale reorganization into the material during sintering thermal treatment, associated to the presence of nanoparticles in the green pellet that sinter at low temperature
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Agostinelli, Simone. "A compartmentalised microchip platform with charged hydrogel to study protein diffusion for Single Cell Analysis." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20333/.
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Within one tumor, cancer cells exist as different sub-populations due to the variations in expression of crucial bio-markers. The prevalence of even minor cell sub-populations can determine overall cancer progression and treatment response. Single-cell protein analysis is a way to identify these cell sub-populations; therefore we developed a microfluidic platform with ultrahigh-sensitivity for single-cell protein analysis. As the key step to develop such a platform, protein migration under the application of an electric field has to be understood. COMSOL multi-physics software is used as a tool to understand the protein migration in microfluidic channels, which contain ion-selective hydrogels as the separation matrix. The objective of this thesis work, is to minimize the protein losses to diffusion and to maximize the fluorescent signal in order to quantify the protein expression in single cells. The novelty of this work lies in the use of ion-selective hydrogels to eliminate the diffusional losses and separate the proteins based on their mass and charge. This thesis project has been performed thanks to an Erasmus fellowship at MCS Department of the University of Twente.
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SENEDA, JOSE A. "Separação e recuperação de chumbo-208 dos resíduos de tório terras raras gerados na unidade piloto de purificação de nitrato de tório." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11424.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Magacho, Ana Luísa Ferreira. "Avaliação de técnicas de separação combinadas para a purificação de xilose visando a obtenção de bioprodutos." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/97/97137/tde-20092012-121705/.
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O presente trabalho teve como objetivo avaliar o uso combinado de processos de separação, visando a adequação do substrato rico em xilose (hidrolisado de bagaço de cana) para a obtenção de produtos por via fermentativa. Foram estudados processos como coagulação e precipitação seletiva de impurezas coloidais, separação com membranas de microfiltração e ultrafiltração e resinas de troca iônica, tendo como ponto de partida o hidrolisado concentrado 5,56 vezes (hidrolisado H1). Na avaliação dos ensaios de coagulação e precipitação foi utilizado planejamento fatorial fracionado, o qual auxiliou o estudo da performance de agentes coagulantes (policloreto de alumínio e polieletrólito aniônico), em diferentes concentrações, pHs e temperaturas. Como variável resposta foi determinado a redução de compostos fenólicos, resultando numa diminuição final de 32,67% e num modelo matemático que representa os parâmetros envolvidos no processo:[C. Fenólicos] = 13,82 + 4,54xpH + 0,03xPAC - 0,58xpH2 + 0,19xPAC2 - 0,25xpHxPAC. Após a determinação das melhores condições experimentais desta etapa, aplicou-se este modelo numa escala 36 vezes maior, resultando em uma diminuição de 10,49% destes contaminantes, produzindo o hidrolisado H2. Este hidrolisado foi percolado por resinas, e assim, determinou-se a série de resinas de troca iônica mais eficiente (série I: Amberlyst 15Wet, Amberlite FPA98, Amberlite 252Na e Amberlite IRA96). Esta etapa proporcionou uma redução de 96,29% no índice de cor, 98,72% dos compostos fenólicos, 74,19% do hidroximetilfurfural, 55,56% de furfural e 52,03% de ácido acético, utilizando um volume de leito de 20 mL, por coluna de resina. O hidrolisado H2, também, foi utilizado para a determinação do melhor modo de permeação por membranas de separação. Neste caso, optou-se em utilizar somente a membrana de ultrafiltração. A permeação do hidrolisado H2 por esta membrana resultou no hidrolisado H3, e em reduções de 12,50% de ácido acético, 33,00% de compostos fenólicos e 54,29% no índice de cor. Assim, o hidrolisado H3 foi percolado pela série de resinas mais eficiente, obtendo ao final uma diminuição de 63,29% do ácido acético, 75,86% de furfural, 77,78% de hidroximetilfurfural e 88,09% dos compostos fenólicos, promovendo uma redução de 90,90% no índice de cor. A seguir, o hidrolisado purificado foi submetido a fermentações para a produção de xilitol e etanol. Essas bioconversões foram aptas a produzir 0,250g/L.h de xilitol e 0,265g/L.h de etanol além de apresentarem rendimentos de 0,68g/g de xilitol por xilose consumida e 0,30g/g de etanol por xilose consumida. Estes resultados indicam a boa fermentabilidade do hidrolisado tratado pelo processo combinado proposto.This study evaluated the combined use of separation processes, seeking the adequacy of the substrate rich in xylose (hydrolysate of sugar cane bagasse) in the attainment of products from fermentative processes. During this research processes as coagulation and precipitation of selective colloidal impurities, microfiltration and ultrafiltration membranes separations and ion exchange resins were studied, taking as its starting point a hydrolysate concentrate 5.56 times (hydrolysate H1). During the tests of coagulation and precipitation a fraction factorial design was applied, which helped the study of coagulating agents performance (aluminum polychloride and anionic polyelectrolyte) in different concentrations, pH and temperatures. The response variable utilized was phenolic compounds reduction resulting in a drop of 32.67% and the mathematical model that represents the parameters involved in the process was: [C. Fenólicos] = 13.82 + 4.54 xpH + 0.03 xPAC - 0.58 xpH2 + 0.19 xPAC2 - 0.25 xpHxPAC. After determining the best experimental conditions of this step, this model was applied on a scale 36 times greater resulting in a decrease of 10.49% on contaminants, producing the hydrolysate H2. This hydrolysate was percolated through resins and determined the sequence of ion exchange resins more efficient; Serie I (Amberlyst 15Wet, Amberlite FPA98, Amberlite 252Na and Amberlite IRA96). This step reduced 96.29% in the index of color, 98.72% of phenolic compounds, 74.19% of hydroxymethylfurfural, 55.56% of furfural and 52.03% acetic acid, using a bed volume of 20 mL for each resin column. The hydrolysate H2 also was used to determine the best way of membranes permeation. In this case, opted to use only the ultrafiltration membrane. The permeation of the hydrolysate H2 through membrane resulted the hydrolysate H3, and showed reductions of 12.50%, 33.00% and 54.29% in acetic acid, phenolic compounds and index of color, respectively. Thus, the hydrolysate H3 was percolated through the resins series more efficient, obtaining a decrease of 63.29% of acetic acid, 75.86% of furfural, 77.78% of hydroxymethylfurfural and 88.09% of phenolic compounds, promoting a reduction of 90.90% in the index of color on the finish treatment. So this hydrolysate purified was subjected to fermentations for the production of xylitol and ethanol. These bioconversions were able to produce 0.250 g/L.h of xylitol and 0.265g/L.h of ethanol and showed xylitol yield from xylose of 0.68g/g and ethanol yield from xilose of 0.30g/g in ethanol. Theses results indicate the good fermentability of the hydrolysate treated by proposed combined process.