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1
Soudani, Allaoua. "Conception et développement d’un processus innovant pour l’intensification des transferts de chaleur et de masse dans un adsorbeur de machine frigorifique à adsorption et intégration des prototypes expérimentaux dans une plateforme d'émulation de la Grande Région". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0001.
Abstract (sommario):
Le dérèglement climatique auquel nous assistons nous oblige à repenser nos unités de production d’énergie. En 2050 le besoin en froid dans le monde engloutira 37% de la production mondiale d’électricité et ajoutera plus de 2 milliards de tonnes de CO₂ par an dans l’atmosphère. Les machines frigorifiques à adsorption sont une alternative avec un grand potentiel mais la technologie de l’adsorption est encore mal comprise. Cette thèse apporte une nouvelle approche par l’analyse fréquentielle des dynamiques de transfert de chaleur et de masse au sein du matériau d’un adsorbeur et pose les premiers éléments de construction d’un modèle numérique du phénomène d’adsorption dans un grain de silica gel. La construction d’un banc prototype pour les tests des futurs adsorbeurs a permis d’identifier les problèmes complexes lors des couplages entre adsorbeur, évaporateur et condenseur. L’intégration par émulation d’une machine prototype dans le réseau de la grande région RCC|Kn a contribué à approfondir le futur modèle numérique global dans toutes ses dimensions. L’interconnexion des plateformes de la grande région a posé les premiers jalons importants du réseau RCC|Kn. Le test de plus de 60 h a démontré une grande stabilité tant dans les infrastructures matérielles que logicielles. Ce nouveau réseau apporte de nouvelles perspectives dans divers domaines tels que l’analyse des données, l’apprentissage automatique, les centres de données, les jumeaux numériques ou l’intégration de flux de données externesThe climate change we are witnessing is forcing us to rethink our energy production units. By 2050 the world's need for cooling will consume 37% of the world's electricity production and add more than 2 billion tonnes of CO₂ per year to the atmosphere. Adsorption refrigeration machines are an alternative with great potential but the adsorption technology is still poorly understood. This thesis provides a new approach to the frequency analysis of heat and mass transfer dynamics within the material of an adsorber and lays the foundation for the construction of a numerical model of the adsorption phenomenon in a silica gel grain. The construction of a prototype bench for the testing of future adsorbers has made it possible to identify the complex problems in the coupling between adsorbers, evaporators and condensers. The integration by emulation of a prototype machine in the RCC|Kn large area network has contributed to deepen the future global numerical model in all its dimensions. The interconnection of the platforms of the large region has laid the first important milestones of the RCC|Kn network. The test of more than 60 hours has shown a high stability in both hardware and software infrastructures. This new network opens up new perspectives in various fields such as data analysis, machine learning, data centres, digital twins or the integration of external data streams
2
Hamou, Mohamed. "Evaluation of the reverse flow reactor concept for the homogeneous molecular catalysis and case study of methyl oleate metathesis". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1122.
Abstract (sommario):
Le réacteur à inversion de flux pour retenir et recycler la chaleur est une technologie efficace qui intègre la réaction chimique et la réutilisation de la chaleur dégagée lors de la réaction. Cette technologie a été considérablement commercialisée et industrialisée, vue l'amélioration de la productivité du réacteur et vue l'intensification du procédé qu'elle offrirait. Par analogie chaleur-matière, il a été voulu, par l'actuel travail de doctorat, évaluer la technologie d'inversion de flux et la combinaison de la réaction chimique et de la séparation et la rétention du catalyseur (matière) dans un seul réacteur adsorbeur multifonctionnel. La métathèse des oléfines qui utilise des catalyseurs moléculaires -qui ne sont pas/ ne peuvent pas être efficacement et parfaitement immobilisés et hétérogénéisés sur un support solide- peut être réalisée dans le réacteur adsorbeur à inversion de flux, qui prétend permettre de séparer, de recycler et de retenir les catalyseurs. La réaction cible dans cette thèse est l'homo-métathèse de l'oléate de méthyle. D'abord, un modèle cinétique pour décrire cette réaction et la transformation du réactif a été développé et proposé en suivant une approche micro-cinétique. Ensuite, ce modèle a été ajusté par rapport aux résultats expérimentaux pour optimiser et accéder aux paramètres cinétiques de la réaction. Le modèle cinétique, ainsi obtenu, permettra après son intégration dans le modèle du réacteur adsorbeur à inversion de flux, de prédire la conversion du réactif et sa concentration à la sortie. Le réacteur adsorbeur à inversion de flux, a été étudié et évalué, par la modélisation et par une étude théorique calculatoire, pour avoir une meilleure compréhension de son comportement, et aussi de l'influence des conditions opératoires sur le procédé (perte de catalyseur, conversion, productivité, etc.). Le design de réacteur qui a été proposé dans cette étude et ce travail est une colonne à lit fixe d'adsorbant, avec inversion de flux. Les résultats de simulation du réacteur adsorbeur à inversion de flux pour retenir et recycler les catalyseurs moléculaires ont montré l'intensification du procédé que peut offrir cette technologie en se référant à un réacteur continu conventionnel (réacteur tubulaire monophasique). Il a été montré aussi qu'il n'est pas possible d'atteindre un régime permanent, sans appoint et rajout du catalyseur pour compenser les pertes, dues aux phénomènes physiques indissociables au réacteur. Par la suite, un dispositif expérimental a été construit pour vérifier et valider les résultats de simulations ainsi obtenus, et aussi pour démonter, à l'échelle pilote, la faisabilité de la technologie d'inversion de flux avec adsorption pour séparer l'adsorbé et le retenir à l'intérieur de la colonne. Et similairement au réacteur à inversion de flux pour le recyclage et la réutilisation de la chaleur, le réacteur adsorbeur à inversion de flux pour séparer et recycler le catalyseur, peut lui aussi, avoir un comportement asymptotique sous certaines conditions opératoires, et s'approcher du fonctionnement du réacteur adsorbeur à contre-courant. Par la modélisation et le calcul numérique, il a été établi le domaine des conditions opératoires dans lesquelles, les réacteurs adsorbeurs à inversion de flux et à contre-courant sont équivalents. Le modèle asymptotique à contre-courant permet de calculer et de pré-dimensionner plus rapidement le réacteur à inversion de fluxThe reverse flow reactor for heat trapping is an efficient technology that integrates the chemical reaction and the recovery of the heat of the reaction. This technology was widely commercialized and applied in industry because of the reactor productivity enhancement and the process intensification it offers. By heat-matter analogy, we wanted, in this thesis, to evaluate the reverse flow technique and the combination of the chemical reaction with the trapping and the recycling of the catalyst (matter) in one single multi-functional adsorber reactor. The metathesis of olefins that uses molecular catalysts -which are imperfectly immobilized and heterogeneized on the solid support- can be performed in the reverse flow adsorber reactor that claims to separate, recycle and trap the catalyst. The targeted reaction is the self-metathesis of methyl oleate. Thus, a kinetic model of the reaction was developed using a micro-kinetic approach. The obtained kinetic model was fitted to the experiences to get the kinetic parameters values. Then, the kinetic model can be integrated in the reverse flow adsorber reactor model to predict the conversion and the outlet methyl oleate concentration. The reverse flow reactor adsorber was evaluated and studied (by modeling and theoretical study) to have a better understanding of its behavior, and of the operating parameters influence on the process (catalyst leaching, conversion, productivity, etc.). A single fixed bed adsorption column is proposed as a design for the reverse flow adsorber reactor. The simulation results show the process intensification that offers the reverse flow adsorber reactor for catalyst trapping in comparison with a conventional continuous reactor (continuous flow tubular reactor). They also show that it is not possible to reach a stable operation and a permanent regime without catalyst makeup that compensate the leaching. Then, an experimental setup was built to verify, to validate the simulations results, and to demonstrate, at the pilot scale, the feasibility of the reverse flow technology to separate and to trap the adsorbate inside the adsorber. And similarly to the reverse flow reactor for heat trapping, the reverse flow adsorber reactor for catalyst trapping and separation can have an asymptotic behavior under certain operating conditions, and approaches the operation of a counter current adsorber reactor. By modeling and numerical calculation, it has been determined the operating conditions, at which, the reverse flow and the counter current adsorber reactors are equivalents. The counter current asymptotic model allow a rapid reverse flow reactor computing and pre-design
3
Štěpánek, Josef. "Konstrukční návrh adsorbéru". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231295.
4
Reinhardt, Sylvia. "Herstellung und Modifizierung massgeschneiderter Adsorberpolymere für die Reinigung von Abwässern und Abluft". [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975903691.
5
Müller, Dirk. "Herstellung von kohlenstoffhaltigen Adsorbentien aus polymeren Ausgangsprodukten unter Anwendung eines neuentwickelten Pyrolysereaktors". [S.l. : s.n.], 2000. https://fridolin.tu-freiberg.de/archiv/html/VerfahrenstechnikMullerDirk916838.html.
6
Tai, Chi-Chih. "Novel adsorbent hollow fibres". Thesis, University of Bath, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437601.
7
Whiley, G. S. "Dynamics of adsorbed polymers". Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382705.
8
Abufares, Assanousi. "Optimal operation of the Claus process in a cyclic adsorptive reactor". Aachen Shaker, 2008. http://d-nb.info/992750407/04.
9
Mackensen, Alexander [Verfasser]. "NOx-Minimierung durch Einsatz passiver NOx-Adsorber / Alexander Mackensen". Clausthal-Zellerfeld : Universitätsbibliothek Clausthal, 2012. http://d-nb.info/1026658756/34.
10
Lascelles, Dominique. "Quantification of adsorbed flotation reagents". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80118.
Abstract (sommario):
Collector interaction with mineral surfaces has long been studied. Little work has been done, however, on directly quantifying reagent adsorption, certainly under industrial process conditions. The use of a novel surface analysis technique, Headspace Analysis Gas-phase Infrared Spectroscopy (HAGIS), is suggested for quantification of adsorbed reagents in mineral processing.As a first exercise, a test system of xanthate adsorption onto lead sulphide minerals was studied. A survey of possible calibration standards (pure xanthate, a synthetic lead-xanthate, galena (PbS) and a lead sulphide ore conditioned with xanthate) resulted in linear curves for all four cases. The quantification of isopropyl xanthate adsorption onto batch flotation products (concentrate and tail) was used to determine that ore standards gave the most accurate results.
The technique was also tested for quantification of adsorbed amines. Two collectors, dodecylamine and diphenylguanidine, and a depressant, triethylenetetramine, were studied. A common calibration curve was prepared using diphenylguanidine adsorbed on Inco matte. Results show that the HAGIS technique can easily be used to quantify adsorbed amines.
It is concluded that the HAGIS technique is a powerful new tool for the quantitative determination of adsorbed reagents. The xanthate study showed the use of ores as standards produces the best calibration. The amine study introduced the possibility of analyzing reagent mixtures.
11
An, Shuwang. "Neutron scattering from adsorbed species". Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297936.
12
Smith, Linda J. "Structural studies of adsorbed proteins". Thesis, University of East Anglia, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320864.
13
Кустовська, Антоніна Дмитрівна, Олена Іванівна Косенко, Вячеслав Васильович Трачевський e Олена Володимирівна Ткаченко. "Preparation of metal-containing zeolites by plasma modification". Thesis, XIII Ukrainan-Polish Symposium Teoretical and Experimental Studies of Interfacial Phenomena and their Technological Appli-cations, September 11-14, 2012, Kyiv – Ukraine, p. 69, 2012. http://er.nau.edu.ua/handle/NAU/28838.
Abstract (sommario):
Application of low-temperature plasma for metal-containing catalyst synthesis
leads to several advantages. The first is the achievement of homogenous and finally dispersed
distribution of metallic clusters. The other advantage of plasma chemical method is fast
and cheap way of zeolites modifying.
14
López-Aranguren, Oliver Pedro. "Functionalized adsorbent materials using supercritical CO2". Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/284975.
Abstract (sommario):
La silica (SiO2) porosa es uno de los adsorbentes históricamente más utilizado a nivel industrial en multitud de procesos. Sin embargo, el crecimiento acelerado de la demanda de nuevos materiales basados en nanotecnología y de nuevos procesos límpios y sostenibles ha hecho necesario el desarrollo de adsorbentes con nuevas o mejores propiedades fisico-químicas. Una de las opciones más empleadas para modificar la silica porosa es la incorporación de moléculas orgánicas con grupos funcionales dando lugar a materiales híbridos en los que se combinan las propiedades de ambos componentes. En esta tesis doctoral, se ha optado por el uso de dióxido de carbono supercrítico (scCO2) como disolvente para llevar a cabo ésta funcionalización. Estos procesos supercríticos, diseñados como sostenibles, actúan como sustitutos de técnicas convencionales que emplean disolventes orgánicos.
En esta tesis se ha trabajado principalmente con matrices de sílica amorfa de poros structuralmente ordenados (MCM-41, 4 nm) y de poros desordenados (silica gel, 4-9 nm), analizándose sólo marginalmente las propiedades conferidas mediante la funcionalización a matrices cristalinas microporosas tipo zeolitas. Como agentes funcionalizantes, se han estudiado alkyl- y aminosilanos (octiltrietoxisilano y (methylamino)propyltrimethoxysilane ) y la aziridina que mediante una reacción de polimerización catalizada por CO2 forma la polietilenimina (PEI) dentro de los poros de la sílica, dando lugar a una red polimérica hiper-ramificada de grupos amino. Se trata de un método novedoso que únicamente requiere CO2 comprimido como reactivo y catalizador de la reacción de polimerización de la aziridina, que habitualmente requiere el empleo de disolventes orgánicos, catalizadores sólidos, altas temperaturas y largos tiempos de reacción. La funcionalización de silica porosa con aminosilanos en scCO2 es de mayor complejidad que en el caso de los alquilsilanos, ya que la alta reactividad entre los grupos amino y el CO2 da lugar a la formación de carbamatos insolubles en scCO2. Sin embargo, la reacción de formación de carbamatos pudo ser parcialmente inhibida mediante el control de la presión y la temperatura del medio de reacción.
Los materiales obtenidos se han caracterizado mediante técnicas de estado sólido: adsorción de N2 a baja temperatura, análisis térmico, espectroscopia de infrarojo, método de tritación de Karl-Fischer, difracción de rayos X, espectrometría de masas por MALDI-ToF y difracción de luz estática. No obstante, también se han empleado técnicas de modelado y simulación molecular como herramientas complementarias, que permiten el estudio de estos sistemas de adsorción complejos con mayor nivel de detalle.
La cadena alquílica del alkylsilano confiere al sistema poroso propiedades hidrofóbicas, preparándose de esta manera materiales útiles en la adsorción de aceites. La funcionalización con moléculas orgánicas que presentan el grupo amino ha permitido la preparación de materiales utilizados en procesos de adsorción y separación de CO2 en mezclas diluidas de gases (secuestro de CO2). Las propiedades adsorbentes de CO2 de las aminosílicas sintetizadas han sido evaluadas combinando técnicas experimentales de adsorción con simulaciones moleculares.
La caracterización de estos materiales se basa en la evaluación de propiedades tales como la capacidad total de adsorción de CO2 y la influencia de la temperatura, la selectividad en la adsorción de CO2 en mezclas de gases, la estabilidad en la adsorción/desorción por ciclos y las cinéticas de estos procesos que han sido determinadas mediante tanto medidas termogravimétricas como mediante isotermas de adsorción de CO2 a diferentes temperaturas.Historically, porous silica (SiO2) is one of the most used adsorbents for a wide variety of processes in the industry. However, the fast grown on the demand of new nanotechnology based materials and sustainable green processes have made necessary the development of adsorbents with improved physico-chemical properties. One of the most applied options to modify porous silica is the incorporation on the surface of organic functional molecules, giving place to hybrid materials, in which the properties of both components are combined. In this doctoral thesis, supercritical carbon dioxide (scCO2) has been used as the solvent to carry out the functionalization processes. Carbon dioxide is a sustainable solvent and its use has been preferred in front of toxic organic liquid solvents, often applied in the traditional methods of synthesis. Amorphous silica matrices with structural ordered pores (MCM-41, 4 nm) and disordered pores (silica gel, 4-9 nm) were selected for the functionalization processes. Besides, the properties conferred by functionalization to microporous crystaline zeolites have been preliminary studied. The modifying agents applied in this thesis were either alkyl (octyltriethoxysialane) or amino (methylaminopropyltrimethoxisilane) silane and aziridine. The later compound is a monomer which polymerizes in presence of CO2, leading to hyperbranched polyethyleneimine (PEI) with multiple amino groups formed into the silica pores. This novel method only requires compressed CO2 as the reagent and the catalyst of the polymerization reaction of aziridine, which usually requires the use of organic solvents, a solid catalyst, high temperatures and long processing times. The functionalization of porous silica with aminosilane in scCO2 is more complex than the case of alkysilanes due to the high reactivity between amino groups and CO2 to form unsoluble carabamate species. However, in this study a protocol was designed to partially inhibit carabamate formation by controlling the pressure and temperature of the reaction media. The obtained materials were characterized using solid state characterization tools: low temperature N2 and CO2 adsorption, thermal analysis, infrared spectroscopy and X-Ray diffraction. Moreover, modeling and simulation methods were used as complementary tools that allowed the study of this complex systems with a high level of detail. The alkyl chain of the alkylsilane induced to the porous system a hydrophobic behavior, hence, obtaining materials candidates for oil adsorption. The functionalization with organic molecules containing the amino group allowed the preparation of materials for the adsorption and separation of CO2 from diluted gases (CO2 sequestration). The CO2 adsorption properties of the synthesized aminosilicas were evaluated combining experimental adsorption tools with molecular simulations. The characterization of these materials was based on the evaluation of the overall CO2 adsorption capacity and the influence of the temperature, the selectivity of the CO2 adsorption in gas mixtures, the stability in the cyclic adsorption/desorption process and the kinetics, which were determined by performing both microbalance and CO2 adsorption isotherms at different temperatures.
15
Ugur, Burcu. "Thermal Energy Storage in Adsorbent Beds". Thesis, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24362.
Abstract (sommario):
Total produced energy in the world is mostly consumed as thermal energy which is used for space or water heating. Currently, more than 85% of total thermal energy consumption is supplied from fossil fuels. This high consumption rate increases the depletion risk of fossil fuels as well as causing a tremendous release of hazardous gases such as carbon dioxide, carbon monoxide, sulfur oxides, nitrogen oxides and particulate matter that effects both environment and human health. Those drawbacks force humankind to search for new technologies, like renewables, to reduce fossil fuel dependency on thermal energy production.
Thermal energy storage in adsorbent beds is one of the resulting technologies. Adsorption is an exothermic process in which a fluid (adsorbate) diffuses into the pores of a porous solid material (adsorbent) and trapped into the crystal lattice. In this system, exothermic adsorption of water vapor from air is carried out by using hybrid adsorbent of activated alumina and zeolite. In previous studies, through literature review, this adsorbent was selected to be the most efficient adsorbent for this process due to its high water adsorption capacity, high heat of adsorption, and stability [Dicaire and Tezel, 2011]. In this study, previous studies started on this project was confirmed and pursued by trying to increase the efficiency of the process and confirm the feasibility and applicability of this system in larger scales.
In this thesis, various zeolite and activated alumina hybrid adsorbents with varying zeolite compositions were screened to find the most efficient adsorbent for thermal energy storage process that gives the highest energy density. Then, existing small column was replaced with a new one, which is 16 times bigger in volume, in order to confirm the feasibility of this process at larger scales. Applicability of on-off heat release in adsorption process was also investigated by conducting several on-off experiments at different on-off time periods. Moreover, exothermic adsorption process was modeled by doing mass and energy balances in the column, water accumulation balance in the pellets, and energy balance in the column wall. Validity of this model was confirmed by comparing it with experimental results at different column volumes, and at different volumetric flow rates. Finally, an overall plant design, capital cost and thermal energy price estimations were done for adsorption thermal energy storage plants for different storage capacities and payback periods.
16
Moore, Bryce Kirk. "Gas-liquid flows in adsorbent microchannels". Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47519.
Abstract (sommario):
A study of two the sequential displacement of gas and liquid phases in microchannels for eventual application in temperature swing adsorption (TSA) methane purification systems was performed. A model for bulk fluid displacement in 200 m channels was developed and validated using data from an air-water flow visualization study performed on glass microchannel test sections with a hydraulic diameter of 203 m. High-speed video recording was used to observe displacement samples at two separate channel locations for both the displacement of gas by liquid and liquid by gas, and for driving pressure gradients ranging from 19 to 450 kPa m-1. Interface velocities, void fractions, and film thicknesses were determined using image analysis software for each of the 63 sample videos obtained.
Coupled 2-D heat and mass transfer models were developed to simulate a TSA gas separation process in which impurities in the gas supply were removed through adsorption into adsorbent coated microchannel walls. These models were used to evaluate the impact of residual liquid films on system mass transfer during the adsorption process. It was determined that for a TSA methane purification system to be effective, it is necessary to purge liquid from the adsorbent channel. This intermediate purge phase will benefit the mass transfer performance of the adsorption system by removing significant amounts of residual liquid from the channel and by causing the onset of rivulet flow in the channel. The existence of the remaining dry wall area, which is characteristic of the rivulet flow regime, improves system mass transfer performance in the presence of residual liquid.
The commercial viability of microchannel TSA gas separation systems depends strongly on the ability to mitigate the presence and effects of residual liquid in the adsorbent channels. While the use of liquid heat transfer fluids in the microchannel structure provides rapid heating and cooling of the adsorbent mass, the management of residual liquid remains a significant hurdle. In addition, such systems will require reliable prevention of interaction between the adsorbent and the liquid heat transfer fluid, whether through the development and fabrication of highly selective polymer matrix materials or the use of non-interacting large-molecule liquid heat transfer fluids. If these hurdles can be successfully addressed, microchannel TSA systems may have the potential to become a competitive technology in large-scale gas separation.
17
Barford, William. "The statistical mechanics of adsorbed polymers". Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328503.
18
Ward, Ross Ritchie. "Keratin adsorbent material for chemical protective clothing". Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/19516/.
Abstract (sommario):
Wool is potentially a valuable adsorbent that has been used for the depletion of airborne gas molecules. The aim of the research is to modify the complex hierarchical structure of wool fibres to form a reticulated internal porous structure within the fibre in order to ultimately enhance the adsorption capacity of wool and/or its composite fibres. In this study, the effects of several chemical treatments and their combinations on the formation of porous microstructure within wool fibres are studied. The techniques studied include oxidation (Formic acid treatment), oxidation/swelling (Ozone treatment in urea hydrogen peroxide solution) and education treatments (Sodium hydroxide treatments) and their combinations. Mesopore and macropore formations were evident after wool fibres and fabrics were treated with individual and consecutive chemical treatments. However, the pore formations after these chemical treatments did not produce materials with specific surface areas comparable to activated carbon. Despite this shortcoming there was evidence of both accessible and inaccessible pore formations within wool fibres. Additional physical selective degradation of raw and chemically modified wool fibres by using both electron beam irradiation using SEM and low pressure oxygen plasma irradiation treatments were identified to expand accessible pores or expose inaccessible pores formed within wool fibres after chemical treatment. Porous wool fibres with reticulated pore structures were evident after exposing the chemical pretreated wool fibres to low pressure plasmas. To enhance the adsorption capacity of the porous wool fibres formed, novel wool aerogel composite wool fibres have been developed. The resultant composite fibres were capable of adsorbing cyclohexane with up to 2.5 w/w% uptake. Also, similar uptakes were evident after testing without any sample pre-heating process. This demonstrates that wool-aerogel composite fabrics are capable of adsorbing VOCs at conditions similar to environments present during the use of CPC.
19
Sleigh, Anne Katherine. "Inelastic electron tunnelling spectroscopy of adsorbed molecules". Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.346406.
20
Collinson, S. J. M. "Structure and dynamics of the adsorbed phase". Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354821.
21
Zerrouk, Taha-El-Amine. "Phase transitions of xenon adsorbed on graphite". Thesis, University of Sussex, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333446.
22
Shah, Iftikhar Ali. "Chemotherapy with activated charcoal adsorbed mitocycin-C". Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275012.
23
Zhang, Jingqing Ph D. Massachusetts Institute of Technology. "Molecular recognition using nanotube-adsorbed polymer complexes". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/79193.
Abstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, February 2013.Cataloged from PDF version of thesis. "December 2012."
Includes bibliographical references (p. 234-249).
We first reported the selective detection of single nitric oxide (NO) molecules using a specific DNA sequence of d(AT) 15 oligonucleotides, adsorbed to an array of near infrared fluorescent semiconducting single-walled carbon nanotubes (AT₁₅-SWCNT). While SWNT suspended with eight other variant DNA sequences show fluorescence quenching or enhancement from analytes such as dopamine, NADH, L-ascorbic acid, and riboflavin, d(AT)₁₅ imparts SWNT with a distinct selectivity toward NO. In contrast, the electrostatically neutral polyvinyl alcohol, enables no response to nitric oxide, but exhibits fluorescent enhancement to other molecules in the tested library. For AT₁₅ - SWCNT, a stepwise fluorescence decrease is observed when the nanotubes are exposed to NO, reporting the dynamics of single-molecule NO adsorption via SWCNT exciton quenching. We describe these quenching traces using a birth-and-death Markov model, and the maximum likelihood estimator of adsorption and desorption rates of NO is derived. Applying the method to simulated traces indicates that the resulting error in estimation is less than 5% under our experimental conditions, allowing for calibration using a series of NO concentrations. As expected, the adsorption rate is found to be linearly proportional to NO concentration, and the intrinsic single-SWCNT-site NO adsorption rate constant is 0.001 s-¹ [mu]M NO-¹. The ability to detect nitric oxide quantitatively at the single-molecule level may find applications in new cellular assays for the study of nitric oxide carcinogenesis and chemical signaling, as well as medical diagnostics for inflammation. Further, we also explored the concept of creating molecular recognition sites using polymer-SWCNT complexes. Molecular recognition is central to the design of therapeutics, chemical catalysis and sensor platforms, with the most common mechanisms involving biological structures such as antibodies[l] and aptamers[2, 3]. The key to this molecular recognition is a folded and constrained heteropolymer pinned, via intra-molecular forces, into a unique three-dimensional orientation that creates a binding pocket or interface to recognize a specific molecule. An alternate approach to constraining a polymer in three-dimensional space involves adsorbing it onto a cylindrical nanotube surface[4-7]. To date, however, the molecular recognition potential of these structured, nanotube-associated complexes has been unexplored. In this work, we demonstrate three distinct examples in which synthetic polymers create unique and highly selective molecular recognition sites once adsorbed onto a single-walled carbon nanotube (SWCNT) surface. The phenomenon is shown to be generic, with new recognition complexes demonstrated for riboflavin, L-thyroxine, and estradiol, predicted using a 2D thermodynamic model of surface interactions. The dissociation constants are continuously tunable by perturbing the chemical structure of the heteropolymer. The complexes can be used as new types of sensors based on modulation of SWCNT photoemission, as demonstrated using a complex for real time spatio-temporal detection of riboflavin in murine macrophages. Cardiac biomarkers troponin I and T are recognized as standard indicators for acute myocardial infarction (AMI, or heart attack), a condition that comprises 10% of U.S. emergency room visits [8]. There is significant interest in a rapid, point-of-cae (POC) device for troponin detection[9]. In this work we demonstrate a rapid, quantitative, and label-free assay specific for cardiac troponin T detection, using fluorescent single-walled carbon nanotubes (SWCNTs). Chitosan-wrapped carbon nanotubes are crosslinked to form a thin gel that is further functionalized with nitrilotriacetic acid (NTA) moieties. Upon chelation of Ni²+, the Ni²+ -NTA group binds to a hexa-histidine-modified troponin antibody, which specifically recognizes the target protein, troponin T. As the troponin T binds to the antibody, the local environment of the sensor changes, allowing for the detection through changes in SWCNT bandgap fluorescence intensity. In this work, we have developed the first near-infrared SWCNT sensor array for specific cTnT detection. Detection can be completed within 3 minutes, and the sensor responds linearly to the cTnT concentrations, with the experimental detection limit of 100 ng/ml (2.5 nM). This platform may provide a promising new tool for POC AMI detection in the future. Moreover, the work presented two useful methods of characterizing two commonly used functional groups, amines and carboxylic acids in soft gels, and this will be useful for other researchers studying hydrogel chemistry. In addition, we synthesized and characterized chitosan-gels both with and without NTA groups, and we compared fluorescence responses upon the addition of four different divalent cations, including Ni²+ , CO², Mg²+, and Mn²+. We proposed a model based Flory-Huggins theory, without any fitted parameters, that is able to describe the fluorescence increase as the Ni²+ concentration increases. The model suggests that the strong binding of Ni²+ onto NTA groups decreases the number of mobile ions in the gel, resulting in a reduction in the ionic chemical potential inside the gel. As a result, the gel de-swells, leading to a local SWCNT concentration increase and an increase in the SWCNT fluorescence signal.
by Jingqing Zhang.
Ph.D.
24
Kent, Anthony Joseph. "An NMR study of adsorbed helium films". Thesis, Royal Holloway, University of London, 1985. http://repository.royalholloway.ac.uk/items/5ad7ff53-aea8-4649-8129-e8ce47a5c292/1/.
Abstract (sommario):
The properties of sub-monolayer Helium-3 films adsorbed on two totally different but planar substrates, Mylar† film and exfoliated graphite have been studied using NMR. The nuclear magnetic relaxation times T1 and T 2 have been measured as functions of fractional monolayer completion, temperature, substrate plane orientation and Larmor frequency using a specially designed and constructed NMR spectrometer system. The results obtained with a Mylar film substrate are consistent3with the formation of patches of solid 3He at regions of preferential adsorption on the substrate. Measurements of T2 m very low coverage 3He films on exfoliated graphite also indicate that the adsorbate forms areas of relatively high density solid, in agreement with the thermodynamic analysis of Elgin and Goodstein. Finally, detailed measurements of T2 as a function of all of the above parameters at low areal densities will help us to characterise the relaxation processes for the fluid phase of 33He on exfoliated graphite. †Mylar is the tradename of poly(ethelene-terephthalate) film, marketed by Du Pont.
25
GUISELIN, OLIVIER. "Structures de polymeres adsorbes. Boucles et miroirs". Paris 6, 1992. http://www.theses.fr/1992PA066498.
Abstract (sommario):
Des chaines de polydimethylsiloxane en bon solvant (toluene) ou en solvant theta (styrene) s'adsorbent a la surface de la solution. La reflexion de neutrons permet de determiner le profil de concentration en monomeres au voisinage de l'interface avec une resolution de dix angstroms. Pour cela, il est necessaire de definir differents modeles de profils possibles, puis de comparer les courbes de reflectivite calculees a partir de ces modeles, avec les courbes experimentales correspondantes. Les previsions theoriques etablies a partir des lois d'echelle ont pu etre confirmees. En mettant une solution concentree de polymeres au contact d'une paroi sur laquelle les monomeres s'adsorbent irreversible, puis en lavant cette paroi, on obtient une couche de polymeres tres differente de celles etudiees dans la premiere partie. Dans ce cas, une etude theorique permet de deduire sa structure a partir de sa distribution de boucles. Une boucle est la partie d'un polymere adsorbe, comprise entre deux monomeres adsorbes. Ce formalisme se generalise au cas des couches de polymeres adsorbes reversiblement
26
Brotherson, Brett Andrew. "Site blocking effects on adsorbed polyacrylamide conformation". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/26509.
Abstract (sommario):
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Yulin Deng; Committee Co-Chair: Peter Ludovice; Committee Member: James Frederick; Committee Member: Lawrence Bottomley; Committee Member: Preet Singh. Part of the SMARTech Electronic Thesis and Dissertation Collection.
27
Billsten, Peter. "Studies on the conformation of adsorbed proteins". Lund : Göteborg University, 1997. http://catalog.hathitrust.org/api/volumes/oclc/39776983.html.
28
Lee, John Edwin 1965. "Molecular orientation distributions in adsorbed protein films". Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282448.
Abstract (sommario):
Understanding and controlling protein adsorption is fundamentally important to the successful development of synthetic biomaterials and implantable chemical sensing devices. However, the study of protein adsorption, and in particular, orientation in protein thin films has been hampered by inadequate methods with which to study weakly absorbing thin protein films. In this work, Integrated Optical Waveguide-Attenuated Total Reflection Linear Dichroism (IOW-ATR LD) coupled with fluorescence emission anisotropy was used to study: (1) the orientation of Mb as a function of the adsorbent surface and surface coverage, and (2) the orientation distributions of cyt c adsorbed to various surfaces. It was found that the average molecular orientation of an adsorbed protein film: (1) is dependent on the chemical and/or physical characteristics of the adsorbent surface, and (2) is dependent on the protein surface coverage. It was also determined that the macroscopic order of an adsorbed protein film is dependent on the number of different types of protein-surface interactions in a given system. If there is one dominant type of interaction between the between the protein and the surface which is limited to a specific region on the surface of the protein, an ordered protein film will be produced. However, as the number of the type of protein-surface interactions increases, the distribution of orientations also increases, leading to a disordered film. Finally, a broadband waveguide coupling device has been developed which allows spectroscopic measurements of submonolayer to monolayer surface coverages of proteins to be performed.
29
Hunt, Terence Peter. "Supercritical fluid extraction of polymeric and adsorbent materials". Thesis, University of Hull, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395430.
30
Ogbuka, Chidi Premie. "Development of solid adsorbent materials for CO₂capture". Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13276/.
Abstract (sommario):
The application of solid adsorbents for gas separation in pre-combustion carbon capture from gasification processes has gained attention in recent times. This is due to the potential of the technology to reduce the overall energy penalty associated with the capture process. However, this requires the development of solid adsorbent materials with large selectivity, large adsorption capacity, fast adsorption kinetics for CO2 coupled with good mechanical strength and thermal stability. In this work, results on CO2 adsorption performance of three different types of adsorbents; a commercial activated carbon, phenolic resin activated carbons and zeolite templated carbons have been reported at atmospheric and high pressures conditions. The commercial activated carbon was obtained from Norit Carbons UK, the phenolic resin activated carbon was obtained from MAST Carbon Ltd., while the templated carbons were synthesized in the laboratory. A commercial activated carbon was used as bench mark for this study. Surface modification of these carbons was also undertaken and their CO2 uptake measurements at ambient and high pressure conditions were recorded. The commercial and templated carbons were modified by functionalising with amine group, while the phenolic resin carbon was modified by oxidation. The textural properties of the adsorbents was examined using the Micromeritics ASAP, while the CO2 adsorption capacities were conducted using the thermogravimetric analyser (TGA) and the High pressure volumetric analyser (HPVA). Textural properties of synthesized templated adsorbents were seen to depend on the textural characteristics of the parent material. The β-type zeolite produced the carbons with the best textural property. Increase in activation temperature and addition of furfuryl alcohol (FA) enhanced the surface area of most of the templated carbons. The textural property of all the adsorbents under study was seen to differently affect the CO2 uptake capacity at atmospheric (0.1 MPa) and high pressure conditions (up to 4 MPa). Micropore volume and surface area of the commercial activated carbons, phenolic resin activated carbons, and the templated carbons greatly influenced the adsorption trends recorded at ambient conditions. Total pore volumes positively influenced adsorption trend for templated carbons, but not the phenolic resin activated carbons at ambient and high pressure. This also positively influenced the adsorption trend for the commercial activated carbons, but at ambient conditions only. The surface area and the micropore volume have no effect on the adsorption trends for the templated carbons and the commercial activated carbons at high pressure conditions. However, these played a positive role in the adsorption capacities of the phenolic resin activated carbons at the same experimental conditions. Micropore volume and surface area of adsorbents play a major role on the adsorption trends recorded for the modified adsorbents at ambient conditions only. No trend was recorded for adsorption capacities at high pressure conditions. Only the oxidized phenolic resin activated carbon showed a positive adsorption trend with respect to total pore volume at high pressure condition. The amine modified commercial activated carbon showed no positive adsorption trend with respect to the total pore volume at both ambient and high pressure conditions, while the amine modified templated carbon showed no adsorption trend with respect to the textural properties at ambient and high pressure conditions. CO2 uptake measurements for the modified and unmodified templated carbon and phenolic resin carbon, were observed to be higher than those of the commercial activated carbon at ambient and high pressure conditions. Maximum CO2 uptake was recorded at 25 oC. At ambient pressure, the phenolic resin carbon (MC11) showed the highest CO2 uptake of approximately 3.3 mmol g-1, followed by the commercial activated carbon (2.4 mmol g-1), then, the templated carbon (2.4 mmol g-1). At high pressure, the templated carbons (β-AC7-2%) showed the highest CO2 uptake (21.3 mmol g-1), followed by phenolic resin carbon (MC4 - 12.2 mmol g-1), and the commercial activated carbon (6.6 mmol g-1). When samples were modified, the amine modified templated carbon and oxidized phenolic resin carbon showed the highest CO2 uptake of 2.9 mmol g-1 each at ambient pressure, followed by the commercial activated carbon (2.7 mmol g-1). At high pressure conditions, the oxidized phenolic resin carbon showed the highest (10.6 mmol g-1) uptake level, followed by the templated carbon (8.7 mmol g-1), and commercial activated carbon (6.5 mmol g-1).
31
Boström, Fanny, e Johanna Lundström. "Biokols struktur och dess förmåga att adsorbera näringsämnen". Thesis, KTH, Industriell ekologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210544.
Abstract (sommario):
Sveriges riksdag har tagit fram 16 miljömål där ett av dem ämnar att minska övergödningen isvenska sjöar och vattendrag. Övergödning är bland annat ett resultat från näringsämnen somläckt från jordbruk. En lösning på övergödningsproblemet skulle kunna vara att samla upp deläckta näringsämnena och återföra dem till åkern. Detta skulle kunna göras med hjälp av biokolsom adsorbent och syftet med detta projekt är att undersöka dessa möjligheter samt biokoletsstruktur. Definitionen på biokol är att det är en heterogen kolliknande substans från hållbart framtagenbiomassa. Den ska även ha ett högt kolinnehåll och användas på ett sådant sätt att den binderupp kolet under en längre tid. Biokol framställs genom pyrolys eller förgasning under högtemperatur och syrefattiga förhållanden. Syftet med användande av biokol som adsorbent ärmöjligheten att kunna skapa ett kretslopp. Biokolet ska först verka som filter i avrinningsdikenvid åkermark för att sedan återföras, mättad med näringsämnen, tillbaka till åkermarken. Vid experimenten användes tre olika kol. Ett grillkol och två olika biokol. Strukturen på deolika kolen undersöktes med en BET-analys. Analysen av grillkolen gav ett orimligt svar menför de två biokolen gavs resultat som ansågs rimliga. Denna analys ger inte ett direkt värde påadsorptionsförmåga hos kolen utan behöver verifieras med ett experimentellt framtagetsamband mellan struktur och adsorptionsförmåga. Ett alternativ till BET-analysen är att göraen jodnummeranalys, som ger värden på adsorptionsförmåga för det undersökta ämnet. Denna analys utfördes inte praktiskt. Två lösningar med olika koncentrationer av Na3PO4 förbereddes och blandades underomrörning med de olika kolen. Två olika omrörningstider användes för att kunna undersökauppehållstidens betydelse. Efter omrörning filtrerades proverna för att få bort kol och de olikafiltraten genomgick en ICP-analys för undersökning av fosforinnehåll. Resultatet som framkomav denna analys var att filtraten hade en högre fosforhalt än vad de initiala lösningarna hade.Förklaringen till detta antas vara att biokolet redan innehöll fosforföreningar som Na3PO4 ut. Problemet med ICP-analysen var att den inte kunde detektera i vilken form fosforn var.Det gick heller inte att detektera kväve i ICP-analysen då luften runt omkringinstrumentet innehåller kväve vilken kontaminerar provet och detekteras i analysen. Enalternativ metod till ICP är att använda spektroskopi som dels kan detektera kväve men ävenolika former av fosfor- och kväveföreningar. Slutsatsen var att analys av biokols adsorptionsförmåga är att den är komplex. BET-analys ären bra metod för att visa struktur på kolen men jodnummer kan vara ett bättre alternativ för attdirekt hitta ett värde på kolets adsorptionsförmåga. För analys av lösningar fungerar ICP enbartför fosfor och därför skulle spektroskopi kunna vara ett bättre alternativ då det kan detekterakväve samt olika former av föreningar.The aim of this project is to create a deeper understanding of biochar’s ability to adsorbnutrients. In the long run the aim is to find a way to use the most suitable structures of biocharfor a maximum adsorption of different kinds of nutrients. The objective of this project is tofind, through case studies and practical experiments, an effective method to examine andanalyze the structure of biochars and their ability to adsorb nitrates and phosphates. The conclusion of the project was that analysis of the biochar’s ability to adsorb is a complexmatter. The BET-analysis is a good method to find the structure of the biochar. However, iodinenumber analysis could be a better alternative to directly find a value on the biochar’s ability toadsorb. The ICP-analysis of the solutions only works for phosphor, therefore spectroscopywould be a better alternative since it also can detect nitrogen and the different compounds.
32
STEVANIN, Claudia. "CHARACTERIZATION OF NANOSTRUCTURED ADSORBENT MATERIALS FOR ENVIRONMENTAL APPLICATIONS". Doctoral thesis, Università degli studi di Ferrara, 2022. http://hdl.handle.net/11392/2488253.
Abstract (sommario):
Environmental pollution has grown to become a problem affecting air, water, soil and ecosystems, mainly due to the growth of the world population in combination with rapid economic development, which has led to a massive increase of global production. Indeed, it is linked to the increased use and complexity of chemicals in many human activities. In particular, the global aquatic environment has been affected by widely spread anthropogenic chemicals and, among these, contaminants of emerging interest (CEC), including pharmaceuticals and personal care products, are of particular relevance as they can have a impact on aquatic life and human health. CEC is a term used to describe synthetic or naturally occurring chemicals or any microorganisms that are not commonly monitored in the environment but have the potential to enter the environment and cause known or suspected adverse effects. The main groups of CEC are pharmaceuticals, personal care products, endocrine disruptors, surfactants, persistent organic contaminants, industrial additives and artificial sweeteners. These contaminants are difficult to trace due to the need for specific detection methods, raising the question of how long these contaminants are prevalent in the ecosystem and how the contamination process can be reversed or reduced. Furthermore, several CECs are unlikely to be removed from conventional wastewater treatment (WWT) processes. Advanced wastewater treatment technologies have been identified to be effective in treating contaminated water, such as nanofiltration, reverse osmosis, ozonation and chemical oxidation. Among the different solutions, adsorption, an established technology, is still considered a reliable and robust method to purify aqueous solutions at low cost and with high efficiency. One of the main advantages of adsorption-based technologies is that they are capable of removing contaminants in very low concentration ranges, an operating condition in which most other separation techniques are poorly efficient due to the small concentration gradients involved. . Furthermore, adsorption is a versatile method that can remove many different organic and inorganic compounds at the same time, provided a suitable blend of adsorbent materials is employed.This thesis focused on evaluating different strategies for removing pollutants from the aqueous matrix. In particular, we have studied methods based on adsorption, and in this case we have selected adsorbent materials different from each other in terms of structure, chemical composition and operating conditions, which can be divided into two classes: (i) microporous silica aluminate adsorbent (zeolites) and (ii) carbon-based mixed matrix (MMM) membranes. In this thesis the adsorbing properties of zeolites towards different classes of CEC (drugs, PFAS and organic contaminants) in aqueous solutions were studied in order to study the efficiency of these siliceous materials in two applications, namely: (1) the removal of contaminants from aqueous matrix, (2) the pre-concentration phase for the analysis of micropollutants. Furthermore, the properties of MMM adsorption towards perfluorinated compounds were also investigated. MMMs are composed of a continuous polymeric phase and a dispersed inorganic filler. This thesis includes a study on advanced oxidation processes for the degradation of pharmaceutical products in an aqueous environment. In particular, two different photocatalysts have been studied: (i) sodium decatungstate and (ii) tungsten trioxide, these semiconductors have the common ability to photoproduce .OH radicals in aqueous solutions.L'inquinamento ambientale è cresciuto fino a diventare un problema che colpisce l'aria, l'acqua, il suolo e gli ecosistemi, principalmente a causa della crescita della popolazione mondiale in combinazione con un rapido sviluppo economico, che ha portato a un massiccio aumento della produzione globale. In effetti, è legato all'aumento dell'utilizzo e della complessità delle sostanze chimiche in molte attività umane. In particolare, l'ambiente acquatico globale è stato influenzato da sostanze chimiche antropogeniche ampiamente diffuse e, tra queste, i contaminanti di interesse emergente (CEC), compresi i prodotti farmaceutici e i prodotti per la cura personale, sono di particolare rilevanza poiché possono avere un impatto sulla vita acquatica e salute umana. CEC è un termine usato per descrivere sostanze chimiche sintetiche o presenti in natura o qualsiasi microorganismo che non è comunemente monitorato nell'ambiente ma ha il potenziale di entrare nell'ambiente e causare effetti negativi noti o sospetti. I principali gruppi di CEC sono prodotti farmaceutici, prodotti per la cura personale, interferenti endocrini, tensioattivi, contaminanti organici persistenti, additivi industriali e dolcificanti artificiali. Questi contaminanti sono difficili da rintracciare a causa della necessità di metodi di rilevamento specifici, sollevando la domanda su quanto tempo questi contaminanti siano prevalenti ell'ecosistema e come il processo di contaminazione possa essere invertito o ridotto. Inoltre, è improbabile che diversi CEC vengano rimossi dai processi convenzionali di trattamento delle acque reflue (WWT). Le tecnologie avanzate di trattamento delle acque reflue sono state identificate per essere efficaci nel trattamento delle acque contaminate, come la nanofiltrazione, l'osmosi inversa,l'ozonizzazione e l'ossidazione chimica. Tra le diverse soluzioni, l'adsorbimento, una tecnologia consolidata, è ancora considerata un metodo affidabile e robusto per purificare soluzioni acquose a basso costo e con alta efficienza. Uno dei principali vantaggi delle tecnologie basate sull'adsorbimento è che sono in grado di rimuovere i contaminanti in intervalli di concentrazione molto bassi, una condizione operativa in cui la maggior parte delle altre tecniche di separazione sono scarsamente efficienti a causa dei piccoli gradienti di concentrazione coinvolti. Inoltre, l'adsorbimento è un metodo versatile che può rimuovere contemporaneamente molti diversi composti organici e inorganici, a condizione che venga impiegata una miscela adatta di materiali adsorbenti.Questa tesi si è concentrata sulla valutazione di diverse strategie per rimuovere gli inquinanti dalla matrice acquosa. In particolare, abbiamo studiato metodi basati sull'adsorbimento, e in questo caso sono stati selezionati materiali adsorbenti diversi tra loro per struttura, composizione chimica e condizioni operative, che possono essere suddivisi in due classi: (i) adsorbente microporoso silico alluminato (zeoliti) e (ii) membrane a matrice mista a base di carbonio (MMM). In questa tesi sono state studiate le proprietà adsorbenti delle zeoliti verso diverse classi di CEC (farmaci, PFAS e contaminanti organici) in soluzioni acquose al fine di studiare l'efficienza di questi materiali silicei in due applicazioni, ovvero: (1) la rimozione di contaminanti da matrice acquosa, (2) la fase di pre-concentrazione per l'analisi dei microinquinanti. Inoltre, sono state studiate anche le proprietà di adsorbimento MMM verso i composti perfluorurati. Le MMM sono composti da una fase polimerica continua e da una carica inorganica dispersa. Questa tesi include uno studio sui processi di ossidazione avanzati per la degradazione di prodotti farmaceutici in ambiente acquoso. In particolare sono stati studiati due diversi fotocatalizzatori: (i) decatungstato di sodio e (ii) triossido di tungsteno, questi semiconduttori hanno la capacità comune di fotoprodurre radicali .OH in soluzioni acquose.
33
Le, Thuaut Philippe. "Fonctionnalisation de supports textiles pour l'élaboration de filtres adsorbeurs de polluants organiques". Lille 1, 2000. http://www.theses.fr/2000LIL10011.
Abstract (sommario):
Les cyclodextrines sont des molecules issues de la degradation enzymatique de l'amidon. On compte trois principales sortes de cyclodextrine. . Le greffage direct de cyclodextrine sur le polypropylene etant impossible, la premiere partie de notre travail a donc consiste a greffer sur le non-tisse des monomeres possedant des fonctions qui seront capables, lors de l'etape suivante, de reagir avec les cyclodextrines ou leurs derives. Nous avons, pour cela, choisi la technique du bombardement electronique qui generent la formation de radicaux libres sur les fibres amorcant ensuite la polymerisation avec greffage du monomere fonctionnel. La deuxieme partie de notre travail a ete d'appliquer nos supports a l'elimination de differents polluants de l'eau tels que les colorants textiles, les pesticides et les derives aromatiques. Nous avons donc realise plusieurs essais afin d'evaluer les capacites des filtres a etre utilises comme systemes adsorbants pour le traitement de l'eau.
34
Hedwig, Michael. "Effektives Kraftstoffdampfmanagement für PKW durch multiphysikalische Modellierung eines mit Phasenwechselmaterialien optimierten Adsorbers". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-201981.
Abstract (sommario):
Das Kraftstoffdampfmanagement in PKW dient der Reduzierung von Kraftstoffdampfemissionen und umfasst deren Entstehung im Tank, sowie Verarbeitung im Adsorber. Im Hinblick auf eine effektive Emissionsreduzierung erfolgt in dieser Arbeit die Entwicklung eines multiphysikalischen Berechnungsmodells, das die Erschließung der Kraftstoffdampfmenge im Tank sowie der Adsorbercharakteristik erlaubt. Gleichzeitig wird eine Methode zur thermischen Adsorberoptimierung durch Phasenwechselmaterialien (PCM) vorgestellt. Letztere nutzen für ihren fest/flüssig-Phasenübergang im Adsorber umgesetzte Prozesswärmen und können damit dessen Arbeitskapazität erhöhen.
Die Modellierung der tankinternen Kraftstoffdampfproduktion erfolgt basierend auf der Berechnung des Dampf-Flüssigkeit-Gleichgewichtes von Mehrstoffsystemen mit realen Fluidmodellen. Zudem wird eine thermodynamische Datenbank erstellt, die es erlaubt, reale ottomotorische Kraftstoffgemische durch Modellkraftstoffsysteme mit deutlich reduzierter Komponentenanzahl abzubilden. Es wird ein detailliertes nicht-isothermes 2D-rotationssymmetrisches Mehrkammeradsorbermodell für kompressible Fluidgemische entwickelt, das die temperaturabhängige Polyschichtsorption in porösen Festbetten wiedergibt und direkt über transiente Randbedingungen mit der instationären Kraftstoffverdampfung im Tank gekoppelt ist. Darin berücksichtigt sind unter anderem anisotrope Wärme- und Stofftransportprozesse innerhalb der Festbetten sowie Randeffekte infolge einer nicht-linearen Porositätsverteilung. Zwischen den Sorptionskammern wird eine dünnwandige Aluminium-Trennwand aus makroverkapseltem PCM integriert, die zur Temperierung der umliegenden Festbetten dient. Hierzu wird auf Basis einer diskontinuierlichen Form der Enthalpy-Porosity-Methode der nicht-isotherme Phasenwechsel im Latentwärmespeicher unter Berücksichtigung der konvektiven Schmelzbewegung modelliert und in Ort und Zeit mit dem Adsorbermodell gekoppelt. Das daraus resultierende partielle Differenzialgleichungssystem wird örtlich über eine Finite-Elemente-Methode und bzgl. der Zeit in Form eines impliziten Mehrschrittverfahrens diskretisiert. Die entsprechende numerische Lösung erfolgt mit Hilfe eines automatisch gedämpften Newton-Verfahrens.
Anhand des Adsorbermodells lässt sich der Einfluss von Randeffekten auf das Ad- und Desorptionsverhalten erschließen, die eine Abhängigkeit von der Festbettgeometrie und des temperaturabhängigen Beladungszustandes zeigen. Diese Sorptionsprozesse werden durch experimentelle Versuchs- reihen an einem hierzu entwickelten Adsorber-Prototyp validiert. Als Ergebnis der numerischen Simulation anwendungsrelevanter Prüfzyklen zur Adsorber-Typisierung resultiert durch den Einsatz von PCM eine Effizienzsteigerung in der Arbeitskapazität des Adsorbers von ca. 14 − 19 %. Zudem kann gezeigt werden, dass auch in Betriebszuständen ohne latenten Phasenwechsel im PCM infolge der konvektiven Bewegung der Schmelze die Sorptionsfähigkeit teilweise um mehr als 11 % ansteigt. Gleichzeitig ist im Vergleich zu der einfachen Vergrößerung des chemischen Sorptionsspeichers der Effekt einer Festbetttemperierung durch PCM partiell bis zu 10 % höher. Durch das einfache Substituieren der klassischen Kunststofftrennwände zwischen den Festbetten durch dünnwandige PCM-Kammern wird die Kraftstoffdampfnachbehandlung ohne relevante Gewichts- und Volumenzunahme des Adsorbers bedeutend verbessert.
35
Bay, Kerem. "Biodiesel : hoch siedendes Absorbens für die Abluftreinigung /". Göttingen : Cuvillier, 2007. http://d-nb.info/987236148/04.
36
Coutts, Euan Ross. "Evaluation of adsorbent haemoperfusion in interventional therapy of sepsis". Thesis, University of Strathclyde, 2016. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=26904.
Abstract (sommario):
Objectives: Sepsis and its sequelae, is one of the major clinical challenges facing intensive care units across the globe, and the greatest cause of intensive care mortality. The aim of the project is to evaluate the suitability of a newly developed adsorbent for use as an interventional therapy in the treatment of sepsis. In order to achieve this, a rat model comparable to the human clinical condition and its symptoms was developed. This rat model was further developed and used to evaluate the effect of deployment of the adsorbent in a miniaturised extracorporeal haemoperfusion circuit. Materials & Methods: In order to achieve this, a rat model (adult male Sprague Dawley 480g-590g) comparable to the acute phase physiological symptoms of asystemic sepsis condition in humans was developed. Sepsis was induced by intraperitoneal injection of lipopolysacharide (LPS). Key physiological characteristics, heart rate, body temperature, and mean arterial blood pressure, were measured dynamically and recorded over a six hour time course. Cytokine profiles were also measured by time interval blood sampling and subsequent ELISAs to characterise progression. In the final phases of experimentation, a miniaturised extracorporeal haemoperfusion circuit was developed to evaluate the impact of deployment in the progression of the condition. Results: Clear trends are evident. Falling blood pressure in the sepsis group overtime when compared to controls. In addition, the sepsis group exhibited a very dynamic temperature response, progressing from hyperthermia to hypothermia over 6 hours. This would appear to be in-line with documented literature and clinical sepsis observations. There was a difference in cytokine upregulation between the control and sepsis groups. Controls exhibited an upregulation in cytokines associated with the surgical procedure, however this was dramatically lower than compared to the LPS-induced sepsis group. With confidence in the sepsis model, an in vivo experimental extracorporeal haemoperfusion circuit involving an adsorbent device was developed to investigate its impact on the sepsis condition in further groups. This resulted in an attenuation of cytokine upregulation, and impact on the physiological markers of sepsis. Cytokine regulation, particularly of TNFα, was dramatically mitigated in the treatment group. A more stable and mitigated falling blood pressure was observed in the treatment group compared to a dramatic response in the sepsis group and a similar observation was also made in regard to body temperature. It is concluded that the deployment of a novel adsorbent is a valid area of further investigation in the treatment of the progression of the sepsis condition based upon the outcome of iterative phases of experimentation using an in-vivo rodent model. Conclusions: The deviation in physiological response and cytokine levels betweenthe sepsis and control groups is in line with documented theory and clinical observations. Progression of the condition in control, sepsis and attenuated progression in experimental treatment models are discussed. The key physiological parameters and inflammatory mediators of the condition were monitored and evaluated to assess the efficacy of this therapy. It is concluded that the deployment of the adsorbent was associated with attenuation of the cytokine response in the LPS induced sepsis animals and modification of the physiological response. This work confirms that the model is a suitable analogue for clinical sepsis and that deployment of a novel adsorbent has a demonstrable mitigating impact upon the progression of the condition representing a valid area for further development of interventional therapy in the ICU setting. The following are the main achievements of this work;- A stable and repeatable in-vivo animal model capable of running a 6 hour time course to model the acute stage of sepsis and a 6 hour control model was developed for use in the Bioengineering facility at the University ofStrathclyde.- This model provided a means of dynamically and iteratively monitoring key physiological parameters and inflammatory mediators of sepsis respectively.- A series of experiments was carried out using these models; clear trends are evident in results which appear to be in-line with documented literature and clinical sepsis observations.- A device was developed for suspending an adsorbent within a miniaturised extracorporeal circuit allowing circulating whole blood to contact the adsorbent presenting a means to assess its impact on the parameters being monitored. - The animal models were further developed to provide a stable and repeatable in-vivo extracorporeal haemoperfusion model capable of running a 6 hour time course and, utilising the test device, suspending the adsorbent within thecircuit; this provided an in-vivo control, sepsis and treatment model.- This is significant as any novel therapy capitalising upon a potential window of intervention must be applicable on a systemic scale due to the nature of the sepsis condition.- A further series of experiments was carried out using these models; clear trends are evident in results which demonstrate a mitigating effect on the progression of the condition in a treatment group compared to an LPS induced sepsis group and a control group.- It is a concluding recommendation that the potential therapy be developed further in order to assess its potential impact upon the progression of the condition and potential applications in the ICU setting.
37
Saiful. "Mixed matrix membrane adsorbers for protein and blood purification". Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/57846.
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Leuthold, Martin [Verfasser]. "Characterization of membrane adsorbers for contaminant removal / Martin Leuthold". Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2012. http://d-nb.info/1029472858/34.
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Bondar, I. V., S. V. Kuzenko, D. H. Han e H. K. Cho. "Synthesis of Polypropylene Fiber / Hydrated Iron Oxide Nanocomposite Adsorbent". Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35589.
Abstract (sommario):
Composite adsorbent based on the polypropylene fibers with chemically bound nanoparticles of hydrated
iron (III) oxide were synthesized by two-stage experiment: radiation-induced graft polymerization of
acrylic acid onto the surface of polypropylene fibers followed by the in-situ formation of hydrated iron oxide
nanoparticles and their stabilization on the fibers‟ surface within the grafted layer. SEM and XRD investigations
revealed a compact homogeneous layer of amorphous nanoaggregates (70-100 nm) formed by iron
hydroxide on the fibers‟ surface. The synthesized nanocomposite fibers were stable in the aggressive medium
for a long time and exhibited good adsorption properties for uranyl ions.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35589
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Qin, Na. "Pyrolysis of De-inked Paper Sludge for Adsorbent Synthesis". Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1272910376.
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Aparicio, Anglès Xavier. "Computational modelling of polyoxometalates adsorbed on metallic surfaces". Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/127146.
Abstract (sommario):
Aquesta tesi està dedicada a la modelització de l’adsorció de polioxometal•lats (POMs) en superfícies metàl•liques. A partir de dades estructures publicades, es plantegen diversos models que, mitjançant metodologies tant quàntiques com clàssiques, pretenen simular l’adsorció de [α-SiW12O40]4- sobre superfícies de plata. Primer s’aconsegueix reproduir el mode d’adsorció i paràmetres estructurals, així com informació espectroscòpica del sistema. Per tal de poder descriure correctament l’estructura electrònica cal introduirmolècules de solvent explícites (aigua) i els contraions (K+ i Cs+) al model. Un cop inclosos, s’aconsegueix reproduir la reduccióespontàniament del POM. En una tercera etapa es realitza un estudi comparatiu dePOMsisoestructurals de diferent càrrega i metall, que posen de manifest la necessitat d’optimitzar els sistemes incloent solvent i contraions per tal de descriure correctament les tendències esperades. Finalment, es planteja una modificació de l’estratègia dissenyada per estudiar sistemes altament carregats sobre nanopartícules d’or.This Thesis is devoted to model the adsorption of Polyoxometalates (POMs) on metallic surfaces. From the structural determination of these composite materials, we propose different models in which the combination of both quantum and classical methodologies, we intent to describe the adsorption of [α-SiW12O40]4- on silver surfaces. Adsorption mode and structural parameters are successfully reproduced, and the spectroscopic data as well. In order to correctly describe the electronic structure, it is compulsory to include explicit water molecules (water) and counterions (K+ and Cs+) in the model. After including the environment, it is possible to reproduce the spontaneous reduction of the POM. Using this strategy a comparative study of metal and charge effects in the adsorption is done. For high charged systems becomes necessary to finally optimise the structure considering the environment for a better description of the adsorption. The latest part of the Thesis is dedicated to the adsorption on gold nanoparticles.
42
Bao, Zhuo. "Synchrotron Radiation Studies of Free and Adsorbed Molecules". Doctoral thesis, Uppsala University, Surface and Interface Science Division, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8610.
Abstract (sommario):
This thesis contains two parts. The first part concerns the research work on free molecules using synchrotron-radiation-related techniques. Auger electron spectra of two free open-shell molecules, O2 and NO, were studied experimentally and theoretically. Photoionization experimental technique with tunable synchrotron radiation source was used to induce core-level electron ionization and obtain the KVV normal Auger electron spectra. A quantitative assignment of O2 normal Auger spectrum was obtained by applying ab initio CI calculations and LVI Auger line shape simulations including the bond length dependence of Auger transition rates. The photon energy dependence of normal Auger electron spectra was focused on with photon energies in the vicinities of core-ionization threshold energies. Consequently, the MAPCI (Molecular Auger Post Collision Interaction) theory was developed. Taking the near-threshold O2 normal Auger spectrum as an example, the two extreme cases of MAPCI effect, “atomic-like PCI” and “molecular PCI”, were discovered and discussed. The effect of shape resonance on near-threshold molecular normal Auger spectrum was discussed taking NO near threshold normal Auger spectra as example.
The second part deals with research work on the chemisorption of small epoxy organic molecules, ethylene oxide, methyl oxirane, on Si (100) surfaces. Synchrotron radiation related techniques, UPS, XPS and NEXAFS, were applied. Based on the valence photoemission spectra, C 1s and Si 2p XPS spectra, the epoxy ring opening reactions of these molecules in chemisorption process were proved. Further tentative search for the surface-adsorbate CDAD effect was performed, and no evident circular dichroism was confirmed.
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Kraikivski, Pavel. "Non-equilibrium dynamics of adsorbed polymers and filaments". Phd thesis, Universität Potsdam, 2005. http://opus.kobv.de/ubp/volltexte/2005/597/.
Abstract (sommario):
In the present work, we discuss two subjects related to the
nonequilibrium dynamics of polymers or biological filaments
adsorbed to two-dimensional substrates.
The first part is dedicated to thermally activated dynamics of polymers on structured substrates in the presence or absence of a driving force. The structured substrate is represented by double-well or periodic potentials. We consider both homogeneous and point driving forces. Point-like driving forces can be realized in single molecule manipulation by atomic force microscopy tips. Uniform driving forces can be generated by hydrodynamic flow or by electric fields for charged polymers.
In the second part, we consider collective filament motion in motility assays for motor proteins, where filaments glide over a motor-coated substrate. The model for the simulation of the filament dynamics contains interactive deformable filaments that move under the influence of forces from molecular motors and thermal noise. Motor tails are attached to the substrate and modeled as flexible polymers (entropic springs), motor heads perform a directed walk with a given force-velocity relation. We study the collective filament dynamics and pattern formation as a function of the motor and filament density, the force-velocity characteristics, the detachment rate of motor proteins and the filament interaction. In particular, the formation and statistics of filament patterns such as nematic ordering due to motor activity or clusters due to blocking effects are investigated. Our results are experimentally accessible and possible experimental realizations are discussed.
In der vorliegenden Arbeit behandeln wir zwei Probleme aus dem Gebiet der Nichtgleichgewichtsdynamik von Polymeren oder biologischen Filamenten, die an zweidimensionale Substrate adsorbieren.
Der erste Teil befasst sich mit der thermisch aktivierten Dynamik von Polymeren auf strukturierten Substraten in An- oder Abwesenheit einer treibenden Kraft. Das strukturierte Substrat wird durch Doppelmulden- oder periodische Potentiale dargestellt. Wir betrachten sowohl homogene treibende Kräfte als auch Punktkräfte. Punktkräfte können bei der Manipulation einzelner Moleküle mit die Spitze eines Rasterkraftmikroskops realisiert werden. Homogene Kräfte können durch einen hydrodynamischen Fluss oder ein elektrisches Feld im Falle geladener Polymere erzeugt werden.
Im zweiten Teil betrachten wir die kollektive Bewegung von Filamenten in Motility-Assays, in denen Filamente über ein mit molekularen Motoren überzogenes Substrat gleiten. Das Modell zur Simulation der Filamentdynamik beinhaltet wechselwirkende, deformierbare Filamente, die sich unter dem Einfluss von Kräften, die durch molekulare Motoren erzeugt werden, sowie thermischem Rauschen bewegen. Die Schaftdomänen der Motoren sind am Substrat angeheftet und werden als flexible Polymere (entropische Federn) modelliert. Die Kopfregionen der Motoren vollführen eine gerichtete Schrittbewegung mit einer gegebenen Kraft-Geschwindigkeitsbeziehung. Wir untersuchen die kollektive Filamentdynamik und die Ausbildung von Mustern als Funktion der Motor- und der Filamentdichte, der Kraft-Geschwindigkeitscharakteristik, der Ablöserate der Motorproteine und der Filamentwechselwirkung. Insbesondere wird die Bildung und die Statistik der Filamentmuster, wie etwa die nematische Anordnung aufgrund der Motoraktivität oder die Clusterbildung aufgrund von Blockadeeffekten, untersucht. Unsere Ergebnisse sind experimentell zugänglich und mögliche experimentelle Realisierungen werden diskutiert.
44
Jones, Daniel Brian. "Micro-mechanical testing of interfacially adsorbed protein networks". Thesis, University of Cambridge, 2002. https://www.repository.cam.ac.uk/handle/1810/251831.
45
Enarsson, Lars-Erik. "Dynamic and Equilibrium Properties of Adsorbed Polyelectrolyte Layers /". Stockholm Stockholm : Fiber- och polymerteknologi Fibre and Polymer Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4697.
46
Bennett, Roger Alexander. "Stimulated dynamics and reaction of small adsorbed molecules". Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388721.
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Hinds, Chantal Simonette. "ESR studies of radical adsorbed on aluminosilicate catalysis". Thesis, Queen Mary, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243865.
48
Mulcahy, Christopher Philip Arthur. "Electronic and vibrational excitations in adsorbed metalorganic molecules". Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287394.
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Bull, Lucy M. "Magnetic resonance studies of adsorbed molecules in zeolites". Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333413.
50
Neumann, Michael. "Experimental investigation of 'He Films Adsorbed on Graphite'". Thesis, Royal Holloway, University of London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500129.