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Wang, Lei. "Cyclic membrane gas separation processes". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0291/document.
Pełny tekst źródłaThis study deals with a systematic investigation of the performance of cyclic membrane gas separation processes. First, a state of the art of membrane separation processes, including material challenges and mass transfer modeling issues is proposed. In a second step, a review of the different theoretical and experimental studies performed on cyclic processes is reported. With respect to the length of the high pressure stage and its fraction in one cycle, these operations are classified into short and long classes. Based on this classification, a systematic analysis of the potential interest of short class compared to steady-state operation performances has been achieved by means of numerical simulation and optimization. In order to improve the performance, the use of MMM in such a process has been further discussed. In parallel with the short class study, a design of novel long class has been proposed. Spectacular advantages with respect to classical membrane-based processes have been highlighted by means of our simulation and optimization studies. Finally, an experimental verification has been performed in order to provide a solid support to this novel process
Teepakorn, Chalore. "Numerical simulation and experimental study of membrane chromatography for biomolecule separation". Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10299/document.
Pełny tekst źródłaMembrane chromatography (MC) is an alternative to traditional resin packed columns chromatography. The solute mass transport in the membrane occurs in convective through-pores rather than in stagnant fluid inside the pores of the resins particles, which is limited by the slow diffusive transport. MC offers the main advantage of reducing diffusion phenomena, shorter residence time and lowered pressures drops, and thus, facilitates rapid purification of large quantities of molecules. A wide range of chromatographic membranes involving different molecules retention mechanisms (ion exchange, affinity, etc...) is now commercialized. Despite their success, the influence of the geometry of the membrane chromatography devices remains relatively unexplored from a theoretical point of view. This doctoral thesis is aimed to clarify some ambiguous points related to this technique
Li, Chia-Ling. "Preparation of poly(vinylidene fluoride) (PVDF) membrane by nonsolvent-induced phase separation and investigation into its formation mechanism". Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20155.
Pełny tekst źródłaThis dissertation shows how the morphology and polymorphism of poly(vinylidene fluoride) (PVDF) membranes prepared by using vapor-induced phase separation (VIPS) and liquid-induced phase separation (LIPS) were tuned by varying the dissolution temperature at which PVDF was dissolved (Tdis) to form the casting solution. We observed a transition temperature denoted by critical dissolution temperature, Tcri, across which the morphology and polymorphism of membranes (obtained by VIPS) drastically changed. The phenomenon was considered as general, as a Tcri was observed for all the three solvents N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF) and the non-solvents, water and a series of alcohols, used in the present study. No matter which Tdis we used, polymer crystallization occurred prior to the L-L demixing. With Tdis above Tcri, the prepared membranes were composed of nodules (mainly in beta crystalline form) and the size of polymer domains decreased as the Tdis decreased. Because the polymer chains could freely coarsen to a large domain during the phase separation, we called the system free coarsening. With Tdis below Tcri, membranes with lacy (bi-continuous) structure (mainly in alpha crystalline form) were obtained. Because the polymer solution gelled during the phase separation, we called the system hindered coarsening. It was proven that PVDF membrane morphology and crystalline polymorphs can be monitored by Tdis and the solvent-nonsolvent exchange rate. These results were discussed in terms of self-seeding effect and competition between the gelation, crystallisation and L-L demixing
Hanafia, Amira. "Étude des mécanismes interdépendants d’élaboration d’une membrane polymère sans solvant organique par une méthode originale de séparation de phase (TIPS-LCST), à partir d’un polymère biosourcé : l’hydroxypropylcellulose". Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20045.
Pełny tekst źródłaPhase separation of polyer/solvent system is the most widespread industrial process to manufacture membranes. Large solvent quantity is usually used whatever the process, hence leading to environmental (coagulation and washing baths treatment) and health (industrial and plant safety) problems.This study focuses on the development of new porous membranes made from hydroxypropylcellulose (HPC), a water soluble polymer, avoiding the use of any organic solvent. Moreover, the thermo-sensitive character of this polymer, characterized by a Lower Critical Solution Temperature (LCST) in water of about 40 °C, enabled to design an original thermally induced phase separation process by temperature increase above the LCST. This study aims (i) to find the ideal polymer solution composition to produce insoluble HPC membrane, (ii) to approach and understand the link between phase separation mechanism by spinodal decomposition, crosslinkig reaction and water extraction by evaporation, (iii) characterize pure water permeability under pressure. On-line monitoring of phase sepration dynamics by phase contrast optical microscopy, crosslinking reaction by rheology and water evaporation by thermogravimetric analysis of the system HPC/water/cross-linking agent ± porogen (PEG200) allowed an understanding of simultaneous and related mechanisms occurring during elaboration (phase separation / cross-linking / water evaporation) and a correlation with HPC membrane morphologies and characteristics in relation with phase separation process parametres. Pure water permeability characterization demonstrated the efficiency of cross-linking and structural strength during several filtration cycles. Furthermore, it has been shown that water permeability of HPC membranes could be controlled in part by the temperature and the applied pressure
Spratková, Aneta. "Intenzifikace stávající čistírny odpadních vod technologií MBR". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392274.
Pełny tekst źródłaŠrámek, Zbyněk. "Návrh technologie čištění bioplynu pro pohon vozidel pomocí membránové separace". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254301.
Pełny tekst źródłaBozorg, Marjan. "Optimization of membrane process architecture". Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0252.
Pełny tekst źródłaMembrane separation is a well-known technology in gas purification, which is applicable in different aspects of the industry. Over the last decades, depending on the required separation performances, it became a viable alternative to several gas separation technologies (adsorption, cryogenics, gas /liquid contactors). To exploit at best this technology, nevertheless, tools to find cost-effective designs and operating conditions are necessary. While experimental optimization approaches applied to different case studies have been investigated extensively, a more generic optimization approach and its validation along different case studies are still missing. The work of this thesis starts with this key observation and tries to fill this gap. The membrane process synthesis is modelled as a nonlinear and non-convex mathematical optimization problem based on a superstructure paradigm covering a wide range of possible units (membrane modules, compressors, and vacuum pumps) and connections as exhaustive as possible. Realistic and detailed cost functions are used as the objective in the optimization. A continues global optimization strategy, that can be considered as the composition of two algorithms: Multistart and Monotonic Basin Hopping (MBH); is presented to solve the aforementioned optimization problem. The efficiency of this overall optimization approach is, first, validated by comparing its solution with the ones presented in the literature. Then, the proposed method is applied to the optimization of several important gas separation cases (CO2 recovery from blast furnace gas, O2/N2 air separation, and biogas and natural gas purification) by increasing the membrane system degree of freedom step by step. Detailed analysis of the results is discussed in terms of process architecture and cost distribution (CAPEX, OPEX)
Gu, Yingying. "Membranes polymères fonctionnalisées par des poly(liquide ionique)s et des nanoparticules de palladium : applications au captage de CO2 et aux membranes catalytiques". Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30157/document.
Pełny tekst źródłaPolymeric support membranes were modified via photo-grafting by poly(ionic liquid)s (polyILs), featuring in the capability to separate CO2 from other gases and to stabilize metallic nanoparticles (MNPs). For CO2 capture, a thin polyIL-IL gel layer was homogenously coated on support hollow fibers. The composite fibers show high CO2 permeance and reasonable CO2/N2 selectivity. For the catalytic membrane, palladium NPs were generated inside a grafted polyLI layer. Compared to colloidal palladium system in a batch reactor, the catalytic membrane, as a contactor membrane reactor, is more efficient in terms of reaction time (ca. 2000 times faster), selectivity and MNP retainability. Theoretical study on reactor modeling, concentration & temperature profiles, and production capacity was done for an overall understanding of the catalytic membrane
Hunter, Paige Holt. "Control of Volatile Organic Compound (VOC) Air Pollutants". Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/38614.
Pełny tekst źródłaPh. D.
MAIDOU, ERIC SIMON-PIERRE. "Extraction, concentration et conversion en acide lactique de lactate de sodium produit par fermentation de lactoserum". Rennes 1, 1988. http://www.theses.fr/1988REN10116.
Pełny tekst źródłaJaouen, Pascal. "Etude des techniques de separation par membrane dans le domaine des peches et des cultures marines : recuperation de proteines solubles de poisson par ultrafiltration, concentration de microalgues marines par microfiltration tangentielle". Nantes, 1989. http://www.theses.fr/1989NANT2003.
Pełny tekst źródłaJaouadi, Meyssa. "Étude d'un procédé hybride de séparation couplant l’électrodialyse à membrane bipolaire et l’échange d'ions : application à la valorisation de solutions diluées d'acide organique". Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0208/document.
Pełny tekst źródłaThis work is dedicated to the study of a hybrid separation process involving bipolar membrane electrodialysis and ion exchange. This study is applied to the treatment of diluted effluents. The aim is first to acquire a theoretical understanding of transfer processes and mechanisms that affect energy consumption of this hybrid system. Then, in a more applied way, the objective is to be able to propose a cell configuration that allows to remove the acid from the treated solution by transferring it to a concentration compartment. This configuration must allow to obtain the highest purification rates as possible while minimizing energy consumption. Criteria aiming at optimizing ion exchange resins (strong or weak) in dilution compartment are proposed. The interest of the introduction of strong cationic resin under H+ form in the concentrated compartment is highlighted, as it enables reducing compartment resistance and hence energy consumption. Furthermore, experimental measurements successively conducted with “decoupled” and “coupled” systems identified resistive contributions of the different elements of the stack. This approach led to the determination of parameters of a model which predicts the resin bed electrical resistance in a given solution. Specific energy consumption (kWh/Kg transferred acid) was evaluated as a function of the desired purification rate. All the work led to recommendations for the cell design and for the choice of operating parameters
Leitner, Loïc. "Étude d'un système de séparation à sélectivité variable et contrôlée usant de membranes de PDMS en milieu organique : application à la séparation de peptides". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0312/document.
Pełny tekst źródłaThe present study aimed to study the ability to build an adaptative and controlled separation process using PDMS membranes for organic solvent nanofiltration (OSN). Despite the well understanding of mechanisms implied in the performances of nanofiltration in aqueous media, the ones conditioning OSN productivity and sieving properties remains unclear. The characterization of the PDMS swelling when put in contact with several solvent and submitted under pressure allowed for correlating the structural conformation of the PDMS membrane to its permeation properties. The study of the influence of different operating parameters on the solvent fluxes has brought significant insights in the understanding of permeation mechanisms. Swelling degree (SL), membrane compressibility under transmembrane pressure (TMP), solvent/membrane affinity and solvent viscosity were pointed out as major parameters governing the filtration through PDMS membranes. The results concluded on a molecular transport attributed to hydraulic transport through the swollen PDMS, which behavior in this state was similar to a porous material. The transport mechanisms were confirmed and deepened with a study of solute retention using homologous series of polyethylenglycols as « model » molecules. The results have shown the ability to build a separation process with targeted performances when using the appropriate operating conditions (TMP, SL, temperature...). Two main categories of impact were shown to condition the selectivity and the productivity of the membrane: the ones attributed to the polymer/solvent layout and the ones concerning the physico-chemical properties of the filtrated solution. Both categories have in addition presented synergetic effects on the process performances. After the demonstration of the ability to vary and control the sieving properties of the PDMS membranes, the nanofiltration system was applied to two concrete case studies: a purification of a hydrazynopeptide after its production via a chemical synthesis and a fractionation of a protein hydrolyzate originating from renewable resources. In both cases, the prospection of the PDMS ability in terms of targeted selectivity and productivity showed interesting results that confirmed a promising development of a separation process among the sieving properties can be regulated by the application of suitable operating conditions
Najarian, Siamak. "Membrane separation methods in medical engineering". Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296835.
Pełny tekst źródłaYe, Pengcheng. "Zeolite Membrane Separation at Low Temperature". Doctoral thesis, Luleå tekniska universitet, Kemiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17447.
Pełny tekst źródłaGodkänd; 2016; 20160215 (penyex); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Pengcheng Ye Ämne: Kemisk teknologi/Chemical Technology Avhandling: Zeolite Membrane Separation at Low Temperature Opponent: Professor Anne Julbe, European Institute of membranes (IEM), Frankrike. Ordförande: Professor Jonas Hedlund, Avd för kemiteknik, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet. Tid: Fredag 22 april 2016, kl 10.00 Plats: C305, Luleå tekniska universitet
Lloyd, Michael C. "Novel materials for membrane separation processes". Thesis, Aston University, 1995. http://publications.aston.ac.uk/9680/.
Pełny tekst źródłaSivertsen, Edvard. "Membrane Separation of Anions in Concentrated Electrolytes". Doctoral thesis, Norwegian University of Science and Technology, Department of Chemical Engineering, 2001. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2100.
Pełny tekst źródłaSaleh, Jehad. "A Membrane Separation Process for Biodiesel Purification". Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19730.
Pełny tekst źródłaHenderson, J. S. "Combined microfiltration and membrane-based affinity separation". Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325959.
Pełny tekst źródłaBanchik, Leonardo David. "Advances in membrane-based oil/water separation". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108950.
Pełny tekst źródłaCataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 117-124).
Oil is a widespread pollutant from oil spills to industrial oily wastewater in the oil and gas, metalworking, textile and paper, food processing, cosmetics, and pharmaceutical industries. A wastewater of particular concern is produced water, an oily waste stream from hydrocarbon extraction activities. Worldwide, over 2.4 billion US gallons of produced water is generated every day. Membrane technologies have emerged as the preferred method for treating these wastewaters; this has allowed operators to reclaim and reuse fresh water for potable, industrial, and agricultural use and to meet waste discharge regulations. Yet, despite their technological predominance, membranes can become severely fouled and irreversibly damaged when bulk and small stabilized oil droplets, emulsions, are present in intake streams. In this thesis, we seek to mitigate these deleterious effects through several means. First we seek to better understand fouling by oil-in-water emulsions on conventional polymeric ultrafiltration membranes. We investigate the decrease in water production over time using model and actual produced water samples with varying solution zeta potentials and make meaningful recommendations to operators based on our observations. Next, we develop a robust multifunctional membrane which can in one step degrade organic pollutants and separate bulk and surfactant-stabilized oil/water mixtures while achieving high fluxes, high oil rejection, and high degradation efficiencies. Finally, we investigate the potential of novel in-air hydrophilic/oleophobic microfiltration and reverse osmosis membranes for their anti-oil fouling performance relative to conventional hydrophilic/oleophilic membranes. Contrary to claims in literature of superior performance, we find that in-air oleophobicity does not aid in underwater anti-fouling due to surface reconstruction of mobile perfluoroalkyl chains in the presence of water. Based on these observations, we discuss opportunities for future research on oil anti-fouling membranes using fluorinated moieties.
by Leonardo David Banchik.
Ph. D.
Zhou, Yi. "Membrane-Based Gas Separation For Carbon Capture". The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595254659184073.
Pełny tekst źródłaEtoumi, Assma S. Abdalla. "Hybrid membrane-distillation separation for ethylene cracking". Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/hybrid-membranedistillation-separation-for-ethylene-cracking(aee59d9f-61a3-4edf-8d22-0123fb6e942e).html.
Pełny tekst źródłaCao, Liming. "Protein Separation with Ion-exchange Membrane Chromatography". Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050405-174109/.
Pełny tekst źródłaMeyer, Faiek. "Hydrogen selective properties of cesium-hydrogensulphate membranes". Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_5047_1233727545.
Pełny tekst źródłaOver the past 40 years, research pertaining to membrane technology has lead to the development of a wide range of applications including beverage production, water purification and the separation of dairy products. For the separation of gases, membrane technology is not as widely applied since the production of suitable gas separation membranes is far more challenging than the production of membranes for eg. water purification. Hydrogen is currently produced by recovery technologies incorporated in various chemical processes. Hydrogen is mainly sourced from fossil fuels via steam reformation and coal gasification. Special attention will be given to Underground Coal Gasification since it may be of great importance for the future of South Africa. The main aim of this study was to develop low temperature CsHSO4/SiO2 composite membranes that show significant Idea selectivity towards H2:CO2 and H2:CH4.
Wu, Dongzhu. "SUBSTRATE DESIGN AND MEMBRANE STABILITY OF MULTILAYER COMPOSITE MEMBRANE FOR CO2 SEPARATION". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1510429230811329.
Pełny tekst źródłaDeng, Shi. "Development of a coarse pore membrane bioreactor with in-situ membrane cleaning /". View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?EVNG%202007%20DENG.
Pełny tekst źródłaFouladvand, Shahpar. "Study of MFI zeolite membrane for CO2 separation". Licentiate thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59614.
Pełny tekst źródłaAshrafizadeh, Seyed Nezameddin. "Solvent extraction and liquid membrane separation of rhodium". Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37698.
Pełny tekst źródłaThe results of the lab-scale experiments using a SLM of Kelex 100 having a surface area of 44 cm2 are reported. The optimum conditions for Rh permeation were found as a feed solution of 2.5 M HCl and a strip solution of 0.1 M HCl. The SLM was quite stable at the optimum conditions with no sign of organic loss or membrane deterioration after 72 hours of operation. It was determined that the HCl activity gradient across the membrane acts as the driving force that "pumps" the non-aquated Rh chlorocomplexes against their concentration gradient. The mechanism of Rh permeation was the ion-pair formation between the protonated Kelex 100 and RhCl6 3- complexes. The rate of Rh permeation was in the order of 10-6 mol.m-2.s-1. The mechanism of HCl and H2O permeation, which were co-extracted along with Rh chlorocomplexes, were found to be the hydration of protons at the low feed acid region and the formation of microemulsions at the high feed acid region. The permeated acid and water were separated from the SLM receiving phase by contacting the latter phase with an organic solution of trioctylamine (TOA). The chlorocomplexes of Rh(III) and acid are readily extracted to the TOA organic phase and subsequently subjected to differential stripping with a concentrated solution of Cl- and a mild NaOH solution, respectively. By interfacing the TOA solvent extraction with the SLM of Kelex 100 highly concentrated solutions of Rh (at least 10 times the initial concentration) and raffinates essentially free of rhodium were produced.
The UV-Visible investigations revealed that the bromocomplexes of Rh undergo aquation to a much lesser extent than that of the chlorocomplexes. The chlorocomplexes of Rh were converted to bromocomplexes by precipitating first the Na(NH4)2Rh(NO2)6 salt and subsequently dissolving that in an HBr solution. The newly formed bromocomplexes of Rh(III) responded very favorably to extraction with Kelex 100. Relatively high distribution coefficients, about 20, and very steep extraction isotherms were generated. The freshly loaded Kelex 100 organic was efficiently stripped upon contact with a strip solution of 6--8 M HCl and a contact time of 10--12 hours. The developed system shows high promise from a practical implementation point of view.
Smith, Daniel Scott. "Investigations into electrochemical membrane separator processes". Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/10262.
Pełny tekst źródłaSibold, Jeremias. "Phase separation of biomimetic membranes:". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0005-12CA-3.
Pełny tekst źródłaShen, Junjie. "Application of membrane technologies in water purification". Thesis, Heriot-Watt University, 2016. http://hdl.handle.net/10399/3147.
Pełny tekst źródłaShi, Xinlong. "Membrane fouling of activated sludge". Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B30731884.
Pełny tekst źródłaWarczok, Justyna. "Concentration of Osmotic Dehydration Solutions using Membrane Separation Processes". Doctoral thesis, Universitat Rovira i Virgili, 2005. http://hdl.handle.net/10803/8534.
Pełny tekst źródłaEn concreto, en este proyecto se utilizaron técnicas de separación por membranas para concentrar soluciones de azúcar procedentes de deshidratación osmótica (en adelante OD). El principal objetivo fue estudiar el potencial de varias técnicas de separación, haciendo hincapié en los flujos obtenidos durante la reconcentración y en la calidad de la solución reconcentrada.
La deshidratación osmótica es un tratamiento que permite una eliminación parcial del agua en un alimento y/o la incorporación de solutos de una manera controlada, respetando la calidad inicial del producto. El proceso consiste en introducir los alimentos en una solución hipertónica, controlando las condiciones de operación para favorecer, en mayor o menor grado la incorporación de solutos y la deshidratación del alimento. La aplicación de OD puede resultar en la mejora de las propiedades nutricionales y funcionales de los alimentos y en la reducción de la energía requerida para la deshidratación. El principal problema de la aplicación industrial de la OD radica en la gestión de la solución procedente del proceso. La reutilización de esta solución plantea una doble ventaja: primero desde el punto de vista ambiental, ya que se elimina un efluente del proceso que a menudo no puede ser vertido directamente, y segundo el ahorro económico que representa la recuperación de las materias primas que muchas veces contienen solutos de importante valor económico.
Los métodos de separación por membrana utilizados para recuperar las soluciones de OD fueron los siguientes: nanofiltración, osmosis directa y destilación osmótica por membranas. La nanofiltración (NF) presenta altos niveles de retención y un menor gasto de energía que la osmosis inversa, y en la industria azucarera se aplica como uno de los pasos en la clarificación y concentración de jarabes. En los procesos de contactores de membranas: osmosis directa (DO) y destilación osmótica por membranas (OMD), a diferencia de los procesos basados en el tamizaje, el flujo depende solamente de la diferencia de potencial osmótico. Las únicas presiones hidráulicas requeridas son las necesarias para bombear la solución de azúcar y la solución osmótica hasta la superficie de la membrana. Estas características hacen que estos procesos presenten como muy prometedores para la reconcentración de soluciones de azúcar de concentraciones elevadas.
Los experimentos de filtración se llevaron a cabo utilizando plantas piloto diseñadas y construidas expresamente para el presente proyecto. Durante todos los procesos de separación por membranas, se empleó como solución modelo una solución de sacarosa a diferentes concentraciones (5-60 ºBrix), debido a que las soluciones aplicadas en la deshidratación osmótica de frutas son habitualmente soluciones de azucares (sacarosa, glucosa o jarabes).
Durante los experimentos de NF se evaluó el funcionamiento de las membranas planas: Desal5 DK (GE- Osmonics), MPF-34 (Koch Membrane), NFT-50 (DSS) y tubulares: MPT-34 (Koch Membrane) y AFC 80 (PCIMembranes). Además de la solución de azúcar de diferentes concentraciones (5-20 ºBrix), se concentraron zumos de pera y manzana.
La reconcentración mediante osmosis directa se realizó utilizando dos modos de operación: off-site e on-site. En el modo off-site, la reconcentración por ósmosis directa se llevó a cabo en una planta de filtración provista de un módulo plano o tubular, dependiendo de la membrana. En el módulo se llevó a cabo la concentración. En el modo on-site, la deshidratación se realizaba conjuntamente con la reconcentración de la solución osmótica. La solución de reconcentración de la osmosis directa en off-site (offsiteDO) fue NaCl, mientras la solución de reconcentración de la osmosis directa on-site (on-site DO) fue una solución de sacarosa más concentrada que la solución osmótica (60 para una solución osmótica de 40 y 68 para una solución de 50 ºBrix). Para garantizar el flujo de agua entre las dos soluciones y altas retenciones de azúcar durante la off-site DO, se utilizaron membranas de NF planas (Desal5-DK y MPF-34) y tubulares (MPT-34 y AFC80). La reconcentración por osmosis directa on-site se levó a cabo empleando una membrana de microfiltración (Durapore, Millipore), ya que la solución de reconcentración (SS) es la misma que la solución osmótica y la alta viscosidad de la SS restringe mucho el flujo de agua si se utiliza una membrana más densa.
En la deshidratación por membranas (OMD) se utilizaron membranas hidrófobas (11806, Sartorius) que presentan una retención teórica del 100 %. Se comparó el rendimiento de dos soluciones de reconcentración: NaCl y CaCl2.
Con el fin de obtener información referente a la influencia de las propiedades de las membranas sobre el desarrollo del proceso de concentración de las soluciones procedentes de la deshidratación osmótica, se realizó un estudio detallado de las propiedades de las membranas aplicadas mediante AFM, SEM, FTIR, ángulo de contacto y medidas de potencial zeta. Con la finalidad de generar soluciones osmóticas para someterlas a reconcentración, y también para disponer de productos procedentes de deshidratación osmótica con soluciones frescas que pudieran compararse con aquellas procedentes de OD con solución reconcentrada, se deshidrataron diferentes lotes de manzana (Granny Smith) con soluciones de sacarosa de 40, 50 y 60 ºBrix. Estas pruebas permitieron determinar también el tímelo de operación para una máxima pérdida de agua con relativamente poca impregnación de las manzanas. Después de cada experimento se analizaron los siguientes parámetros: concentración de azúcar, pH, absorbancia a 420 nm de las soluciones y humedad de las manzanas.
La nanofiltración, aplicada en la primera fase del presente estudio, resultó ser viable solamente para la reconcentración de soluciones de concentraciones hasta 24 ºBrix. El aumento de la temperatura de 25 hasta 35 ºC para las dos membranas tubulares ocasionó un incremento del flujo de permeado, y el mismo efecto tuvo el aumento de presión transmembranaria de 8 a 12 bar.
Se comprobó que el factor más importante para la eficacia del proceso es disponer de una membrana que combine altos flujos y retenciones durante el proceso. La deposición de las partículas de sacarosa y/o los zumos se caracterizó mediante SEM y la topología de la capa filtrante de la membrana se identificó usando AFM. La topología de la capa filtrante de las membranas era diferente para cada una de ellas, a pesar de que todas estaban preparadas con el mismo material (poliamida). En las imágenes de los cortes transversales de las membranas realizados con SEM, se observaron los cambios en la estructura de las membranas producidos por la aplicación de presión durante los experimentos y las altas temperaturas empleadas durante su acondicionamiento. Gracias a las imágenes de SEM se pudo verificar también la eficacia del proceso de acondicionamiento de membranas.
A diferencia de NF, tanto la ósmosis directa como la destilación osmótica por membrana permiten la reconcentración de soluciones concentradas de sacarosa (hasta60 ºBrix). La eficacia de estas dos últimas técnicas se evaluó en unción de los flujos de agua obtenidos.
El sistema de ósmosis directa on-site propuesto para la reconcentración de las soluciones de OD permitió reutilizar las soluciones osmóticas como mínimo cuatro veces. Para la solución osmótica de 40 ºBrix la humedad de las manzanas fue similar utilizando solución fresca o reconcentrada. En cambio, una solución osmótica de 50 ºBrix, la pérdida de agua de las manzanas fue mayor cuando la deshidratación osmótica se llevó a cabo con reconcentración on-site de la solución osmótica. Los análisis de concentración de azúcar de las soluciones osmóticas y de la solución de reconcentración indican que la membrana elegida para los experimentos facilita el transporte óptimo de solutos y agua entre las dos soluciones. Además, el sistema de reconcentración por membrana propuesto es muy sencillo y de bajo coste porque no requiere presurización.
La osmosis directa en off-site proporcionó flujos mucho mayores que los obtenidos con el sistema on-site (1.3 kg/m2h para la solución osmótica de 50 ºBrix respecto a 0.0023 kg/m2h durante on-site DO para la misma solución). Sin embargo, el transporte de solutos de la solución de reconcentración hacía la solución osmótica puede ser considerado un obstáculo para su aplicación a escala industrial.
Los flujos de agua más elevados fueron obtenidos utilizando la OMD (2.01 kg/m2h para la solución osmótica de 50 ºBrix y con CaCl2 con la solución de reconcentración). Otra gran ventaja de este proceso es la retención de solutos que proporciona, hecho confirmado por los análisis realizados.
El estudio sobre el transporte durante los procesos de contactores de membranas indicó que la viscosidad es la propiedad limitante para la solución osmótica y la actividad de agua/alta presión osmótica como la propiedad más importante a la hora de elegir una solución de reconcentración. Para todos los procesos de separación aplicados, el aumento de la concentración de azúcar de la solución osmótica comporta una disminución notable del flujo de agua.
El desarrollo de un posible proceso de deshidratación osmótica con una etapa de reconcentración de la solución osmótica mediante procesos con contactores de membrana ha permitido calcular el área requerida para realizar la reconcentración: 3.6,9.7, 1608 m2 para OMD, off-site DO e on-site DO, respectivamente.
Las conclusiones del trabajo confirman la posibilidad de utilizar procesos por membrana para realizar la reconcentración de soluciones osmóticas. No obstante se ha constatado que técnicas más tradicionales basadas en diferencias de presión (NF) no son
El-Amari, Abdulla Ali. "Separation of acidic gases using hollow fibre membrane contractors". Thesis, University of Salford, 2002. http://usir.salford.ac.uk/26653/.
Pełny tekst źródłaXu, Weihua. "Design and development of a pervaporation membrane separation module". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63128.pdf.
Pełny tekst źródłaOno, Kayoko Gupta Ram B. "Membrane separation in supercritical antisolvent process for nanoparticle production". Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Fall/Theses/ONO_KAYOKO_27.pdf.
Pełny tekst źródłaYunos, Khairul Faezah Md. "Separation and fractionation of proteins using sandwich membrane untrifiltration". Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531982.
Pełny tekst źródłaEtuk, Benjamin Reuben. "Separation of alcohol from beer by liquid membrane technique". Thesis, Heriot-Watt University, 1988. http://hdl.handle.net/10399/984.
Pełny tekst źródłaMarriott, James Ingram. "Detailed modelling and optimal design of membrane separation systems". Thesis, University College London (University of London), 2001. http://discovery.ucl.ac.uk/1349890/.
Pełny tekst źródłaLin, Han. "GRAPHENE OXIDE-BASED MEMBRANE FOR LIQUID AND GAS SEPARATION". University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1595260029225206.
Pełny tekst źródłaWanekaya, Adam. "Novel hyphenated technologies for sensing, separation and sample treatment". Diss., Online access via UMI:, 2005. http://wwwlib.umi.com/cr/binghamton/main/.
Pełny tekst źródłaSvang-Ariyaskul, Apichit. "Chiral separation using hybrid of preferential crystallization moderated by a membrane barrier". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33909.
Pełny tekst źródłaTsao, Sai Cheong Timothy. "Preparation and characterization of nanofiltration membranes fabricated from several selected polymers and their uses in separation process". HKBU Institutional Repository, 2001. http://repository.hkbu.edu.hk/etd_ra/362.
Pełny tekst źródłaJack, U. "Fabrication of wet phase inversion capillary membrane, dimension and diffusion effects". Thesis, Cape Peninsula University of Technology, 2006. http://hdl.handle.net/20.500.11838/895.
Pełny tekst źródłaA protocol already exists for fabrication of a capillary membrane having an internal ultrafiltration skin supported by a finger-like pore structure in the external capillary wall (Jacobs and Leukes, 1996; Jacobs and Sanderson, 1997). These membranes have been produced at the Institute of Polymer Science, University of Stellenbosch, South Africa. Two major applications emerged from the development of these internally skinned membranes. One application was in the production of potable water by Ultra-filtration (UF) from sources containing coloured water. A second application was in the immobilization of a white rot fungus in a ."gradostat" membrane bioreactor. Here a nutrient gradient through the membrane wall and fungal mat can be established and manipulated in order to stimulate continuous production of secondary metabolites (extra-cellular enzymes). These enzymes are useful in the degradation of polycyclic aromatic compounds, notably PCB species in contaminated water and soils (Jacobs and Sanderson, 1997). Two objectives emerged from experiences with the above applications. The first objective was to improve membrane performance in UF applications. In this case a reduction was sought in trans-membrane pressure differential required to attain a desired flux without sacrificing rejection. The pressure required for a given desired flux across a membrane depends on the resistance of the membrane skin layer and of its supporting sub-layer which together comprises the capillary wall and defmes its overall structure. If any of these resistances could be reduced, the overall resistance to transport of water would be reduced. Then it would be possible to operate the membrane at lower trans-membrane pressure differences. On the other hand, operation with higher pressure would also increase flux but require a thicker capillary wall to resist this pressure. In the attempt to optimise these properties of the capillary membrane, capillary membranes produced in the study reported here were tested to find the relationship of flux performance with the structures that resulted from varying key parameters affecting structure and integrity. The objective in the case of immobilizing fungi in membrane bioreactor applications was to attain thicker walls thus providing better support for the fungal mass. The internally skinned capillary membrane has finger-like microvoids that start next to the UF skin layer and extend across the capillary membrane wall and open at the external membrane periphery, giving an ideal structure for retaining the fungal biomass. The idea of a membrane with this type of morphology to immobilize white rot fungi was to anchor the growing fungus within these microvoids which imitate the natural environment in which these organisms live, that is, in the fibrous structure of decaying wood. The requirement to inoculate the microvoids with fungal spores (reproductive cells), implies that they need to be accessible from the outside, requiring a membrane wall that is externally unskinned. In the formation ofthe capillary membrane the processes of formation of the porous UP skin and the finger-like microvoids are mainly governed by diffusion of solvent out of a polymer dope (gel phase) and of non-solvent into the dope phase. Such exchanges are of primary importance between the bore fluid (containing non-solvent) and dope (containing solvent) or between the external spinning bath (high in solvent content) and dope. Diffusion effects also occur between the nascent pore voids and the precipitating polymer matrix. There are also expected to be some convection effects due to shear between the bore fluid and the moving dope gel phase and due to shrinkage ofthe gel phase. The variables selected for experimentation m the study reported here were: the dope extrusion rate (DER); dope composition (viscosity effects); bore fluid flow rate (BFF); bore fluid composition and wall thickness and diameter effects (determined largely by spinneret dimensions). Each of these has an expected effect on membrane structure and its resulting performance. Most were varied over narrow ranges indicated in the literature and by experience to be effective and critical. In addition, the effects of altering the walI thickness were investigated by using two different spinneret sizes. The external spinning bath composition (solvent content) was reported in the literature to be a particularly important parameter in the formation of externally unskinned membranes. Maintaining a high content of solvent in the external spinning bath could prevent skin formation. Too high a solvent content could, however, prevent phase transition and lead to later precipitation ofa dense skin on contact with the non-solvent in the later (humidification and rinsing) steps in the fmishing of the capillary membrane product. The external bath composition was therefore varied so as to find the bath composition that would match the cloud point for the polymer dope employed. As expected, the thickness of the membranes increased with DER increase. However, it was found that there is a critical wall thickness where an external skin layer is formed as a result of increasing the DER. A certain volumetric ratio ofDER to BFF (1,5:1 for this study) was therefore maintained in order to produce externally unskinned membranes. This shows that although the final membrane structure is detennined by the casting dope formulation, the fabrication protocol plays an equally important role in controlling structural properties and perfonnance. There was no significant change with the membrane thickness as a result of changing BFF but the voids became longer and more in number as the BFF was increased. Too high solvent content (99% NMP in this study) resulted in an external skin layer being formed. According to Smolders et.al. (1992), when the solvent content in the external spinning bath is too high, the polymer at the surface of the newly fonned membrane slowly dissolves in the external spinning bath re-forming a dope-like solution. When the newly formed membrane passes through the humidifier, the dope-like solution solidifies to form an external skin. At the same instance, too low solvent (93% for this study) resulted in external skin being fonned. Externally unskinned membranes were formed at 94 and 96% NMP bath composition. The use of a small spinneret resulted in very thin walled externally unskinned membranes.
Wong, Hiu Man. "Removal of pathogens by membrane bioreactor : removal efficiency, mechanisms and influencing factors /". View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20WONGH.
Pełny tekst źródłaIncludes bibliographical references (leaves 93-102). Also available in electronic version. Access restricted to campus users.
Liu, Junqiang. "Development of next generation mixed matrix hollow fiber membranes for butane isomer separation". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/42807.
Pełny tekst źródłaLönnberg, Maria. "Membrane-Assisted Isoform ImmunoAssay : Separation and determination of protein isoforms". Doctoral thesis, Uppsala University, Surface Biotechnology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1861.
Pełny tekst źródłaProteins exist in a variety of isoforms with minor differences, mostly due to their glycosylation patterns, which can modulate their biological functions. It seems to be of clinical relevance to measure the isoform-distribution.
Thesis describes a novel technology named Membrane-Assisted Isoform ImmunoAssay (MAIIA). This technique allows rapid (< 15 min.) isoform determination. It is based on a chromatographic separation combined with immunoassay detection. These steps are performed along a thin, disposable micro-porous chip in which capillary forces maintain the flow. By using anion-exchange as a chromatographic principle the technology has been utilized for the determination of transferrin isoforms in ten minutes. In one variant (the one-dimensional), selected isoforms (carbohydrate-deficient transferrin) are quantified. In a more elaborate variant (the two-dimensional) it was possible to determine the entire isoform profile of transferrin. Isoforms differing by only 0.1 pH unit in isoelectric point could be distinguished.
The chromatography along the microporous bed of nitrocellulose showed very good separation performance with plate heights of 10-20 µm and only minor flow rate variations between individual devices.
The quantitative determination of antibody-captured molecules was performed by using antibodies labelled with carbon black particles. Combined with a detection procedure by means of a flatbed scanner, a highly sensitive and specific immunoassay with a detection limit of 0.13 pM was obtained upon using IgE as a model analyte.
This technology can thus be used to rapidly distinguish proteins with minor structure differences and specifically determine protein isoforms in complex environments, e.g., blood, down in the pM (10-12 M) concentration range.
Lizon, Tatiana Gallego. "Cadmium separation from phosphoric acid using the emulsion liquid membrane". Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/7634.
Pełny tekst źródłaLönnberg, Maria. "Membrane-assisted isoform immunoassay : separation and determination of protein isoforms /". Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2002. http://publications.uu.se/theses/91-554-5250-7/.
Pełny tekst źródłaHarlacher, Thomas [Verfasser]. "Membrane separation processes for Argon plasma gas recovery / Thomas Harlacher". Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1049352165/34.
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