Dissertations / Theses: 'Adsorbent material'

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Ward, Ross Ritchie. "Keratin adsorbent material for chemical protective clothing." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/19516/.

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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.

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Thorpe, Roger. "Heat transfer by forced convection in beds of granular adsorbent material for solid sorption heat pumps." Thesis, University of Warwick, 1996. http://wrap.warwick.ac.uk/34618/.

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A novel adsorption cycle in which enhanced heat transfer between the adsorbent and external heat sinks and sources is achieved by forced convection of refrigerant gas through the adsorbent bed is presented This cycle is further developed by the use of inert beds to store the heat of desorption and sensible heat between phases. The performance and utility of such a cycle will depend on the heat transfer coefficients and pressure drops that result when the refrigerant gas is circulated through the beds The heat transfer and pressure drop characteristics of a bed of granular active carbon were investigated using argon, carbon dioxide and ammonia. Equipment was designed and built to pass a stream of gas through a bed at a controlled rate, pressure and temperature. The pressure drop characteristic was found to conform to Ergun equation and the constants for the application of that relation to a commonly available granular active carbon established. A mathematical model based on a finite difference technique was created and used to predict the progress of a temperature front in the bed and derive the heat transfer characteristics from experimental data. Heat transfer coefficients measured with argon and ammonia appeared inconsistent with each other and after investigations of the data and comparison with established correlations were made it was concluded that carbon during the argon experiments had been contaminated. The heat transfer results with ammonia and carbon were compared with a modified version of the Colburn analogy between heat transfer and pressure loss. A correlation between the Nusselt number and Reynolds number for design purposes was established.

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Tyburce, Bernard. "Application de l'échange ionique à la caractérisation des zéolithes." Poitiers, 1987. http://www.theses.fr/1987POIT2036.

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Bahamón, García Daniel. "New generation adsorbents for gas separation: from modeling to industrial application." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/325690.

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Teniendo en cuenta el rápido aumento de la población y el crecimiento en el consumo de energía como consecuencia de grandes progresos en transporte y tecnología, el desarrollo sostenible es de especial relevancia pues sugiere la búsqueda de formas de mitigar las emisiones de gases de efecto invernadero, incluyendo la captura y almacenamiento de carbono (o utilización), la eficiencia energética, fuentes alternativas de energía y ahorro de energía, como ya se ha sugerido por el protocolo de Kioto y los informes del IPCC. De ahí que en los últimos años se haya dedicado un esfuerzo considerable a desarrollar tecnologías para la captura y almacenamiento de CO2 a partir de fuentes concentradas de emisión. Además de establecer nuevas tecnologías, durante las últimas décadas la ciencia de materiales sólidos porosos se ha convertido en una de las áreas más intensas de investigación y desarrollo para químicos, físicos y científicos de materiales. De hecho, se ha avanzado considerablemente en el desarrollo de nuevos adsorbentes para diversos procesos de separación. Por ejemplo, las estructuras órgano-metálicas (MOFs) han ido ganando considerable atención como materiales prometedores para aplicaciones de almacenamiento y separación de gases, debido a sus propiedades excepcionales. Sin embargo, es necesaria una comprensión a nivel molecular de la adsorción de gases para acelerar el diseño y desarrollo de aplicaciones a la carta. También es fundamental conocer el comportamiento bajo condiciones de humedad e impurezas, como se tiene normalmente en aplicaciones industriales específicas. El trabajo desarrollado en esta Tesis Doctoral destaca el uso de técnicas de simulación molecular para la optimización de procesos relacionados con el medio ambiente. El objetivo general se centra en avanzar en el campo de materiales para la captura y separación de dióxido de carbono a condiciones de proceso. Se considera de manera explícita la influencia del vapor de agua e impurezas, tanto a la luz de los fundamentos de la adsorción como en la aplicación para la captura de CO2 por post-combustión mediante ciclos de adsorción por oscilación. Partiendo de una breve descripción de los fundamentos de la adsorción y de las simulaciones moleculares, se presenta una revisión exhaustiva de estudios recientes de materiales para captura y separación de CO2, proporcionando así información valiosa para su aplicación industrial. Basados en esta revisión, se han estudiado en detalle algunos de los materiales más prometedores para un proceso de adsorción por cambio de temperatura (TSA) basado en simulaciones moleculares, proponiéndose un nuevo procedimiento para la evaluación y optimización de los sistemas de captura en condiciones reales. Dada la gran influencia de trazas de agua en la separación, se investiga también el CuBTC (uno de los MOF más estudiados y estables en agua) en comparación con la zeolita de referencia 13X. Se examina en detalle el efecto de las especies coexistentes, así como la influencia del agua y SO2 en los gases de combustión, con el fin de llegar a una mejor comprensión de la capacidad de adsorción, la selectividad, la localización de las moléculas en el material, las distribuciones de calor isostérico y su relación con el proceso. Asimismo, se han llevado a cabo estudios paramétricos detallados para una investigación comparativa de la separación de mezclas multi-componentes de gases de combustión mediante el uso de otras zeolitas como caolinita y chabacita. Y finalmente, se presenta un trabajo adicional relacionado con otro problema medioambiental: la separación de un contaminante (ibuprofeno) en agua, mediante el uso de carbones activados, usando las mismas técnicas computacionales, demostrando así la versatilidad de las herramientas empleadas para este tipo de sistemas.
Given the rapid increase in population and the growth in energy consumption as a consequence of major developments in transportation and technology, sustainable development is of special relevance, suggesting ways to mitigate greenhouse gases emissions, including carbon capture and storage (or utilization, CCSU), energy efficiency, alternative energy sources and energy savings, as already suggested by the Kyoto’s Protocol and the IPCC reports. Hence, much effort has been devoted in recent years to develop technologies for capture and storage of CO2 from concentrated sources of emission. Apart from establishing new technologies, over the last decades the science of porous solid materials has become one of the most intense areas of research and development for chemists, physicists, and materials scientists. In fact, considerable progress has been made in recent years on the development of novel adsorbents. For instance, Metal Organic Frameworks (MOFs) have been gaining considerable attention as promising nanoporous materials for gas storage and gas separation applications due to their exceptional physical and chemical properties, and have already been demonstrated to be promising materials in the separation of different gases, however, a molecular level understanding of gas adsorption in the pores is crucial to accelerate the design and development of these and other applications. It is also fundamental to know their behavior under moisture conditions and impurities content, as normally found at specific industrial applications. The work developed in this Thesis highlights the use of molecular simulation techniques for optimizing environmental related processes, providing new procedures to assess the use of these materials from their fundamental knowledge until their applications at industrial conditions. The overall objective is to advance in the field of materials for CO2 capture and separation at process conditions. The influence of water vapor and impurities is explicitly considered, both, in the light of the fundamentals of adsorption and in the application for post-combustion carbon dioxide capture by swing adsorption cycles. Starting from a brief description of the fundamentals of adsorption and molecular simulations, a novel throughout review on recent studies of materials for CO2 capture and separation is presented, thus providing valuable information to assess their industrial application. Based on this review, some of the most promising materials for CO2 separation in a Temperature Swing Adsorption (TSA) process have been studied in detail by using molecular simulations (compared to experimental data when available), proposing a new process for the evaluation and optimization capture systems under real conditions. In addition, given the great influence of water as a trace compound on the separation, CuBTC (one of the most studied MOFs, stable in water and with potential for industrial application) has been investigated in comparison to the benchmark zeolite 13X. The effect of the coexisting species as well as the influence of water and SO2 in flue gas is examined in detail in order to reach a better understanding of the adsorption capacity, selectivity, adsorption density location and isosteric heat distributions. And finally, detailed parametric studies have been carried out for a comparative computational investigation for separating of multi-component mixtures of flue gas by using other representative zeolites such as kaolinite and chabazite. Additional work, related to another environmental problem: the separation of a pollutant (ibuprofen) in water, by using activated carbons, is also presented here, demonstrating the versatility of the tools used for these types of systems.

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Su, Lingcheng. "Soil contamination and plant uptake of metal pollutants released from Cu(In, Ga)Se₂ thin film solar panel and remediation using adsorbent derived from mineral waste material." HKBU Institutional Repository, 2018. https://repository.hkbu.edu.hk/etd_oa/552.

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The Cu(In,Ga)Se2 (CIGS) thin-film solar panels (TFSPs) are widely used in integrated photovoltaic (PV) and solar power systems because of their perfect PV characteristics and ductility. However, the semiconductor layers of these panels contain potentially toxic metals. In this study, the potential environmental pollution arisen by CIGS TFSP treated as construction trash at the end of their useful life was examined. Acid extraction was used to simulate leaching toxicity followed by burying CIGS TFSP material in different soils, namely a synthetic soil, a Mollisol, and an Oxisol, to determine whether metal pollutants might be released into the soil. A vegetable, Brassica parachinensis L. H. Bariley (VegBrassica), was selected to grow in these polluted soils to investigate the uptake of metals and their bioaccumulation. The simulative remediation of contaminated soils was carried out using a remediation module created by the combination of activated carbon and modified mineral waste material (MMWM) in this research. The activated carbon derived from the waste biomass material was produced by an environmental friendly method, and the MMWM was obtained through a thermal dehydroxylation treatment. The physiochemical properties of MMWM, with focusing on mineral phase transformation, were related to the changes in surface morphology due to dehydroxylation occurred during the process of thermal treatment of MMWM samples, and the adsorption performances of metal (lead, Pb) and organic compound (methyl orange, MO) onto this newly modified MMWM were studied. Furthermore, an end-of-life treatment method was designed and proposed for harmless disposal of CIGS TFSP. Various metals, including Pb, zinc (Zn), nickel (Ni), chromium (Cr), gallium (Ga), copper (Cu), indium (In) and aluminum (Al) were found to be released into the soil and caused contamination when scrapped end-of-life CIGS TFSP were buried, and the rates of metal release changed with the variations of both the amounts of CIGS TFSP material in the soil and the soil properties. The increases in concentrations of heavy metals such as Zn, Cu, Ni, Ga, Pb, In, and Cr were correlated with the amounts of CIGS TFSP material added in soils. The Pollution Index and the Nemerow Contamination Index calculated from our results confirmed that, when buried, the CIGS TFSP material polluted the soil. Plants grew well in the synthetic soil and the Mollisol, but those in the Oxisol showed prominent signs of chlorosis and died after 30 days. The bioaccumulation factor (BF) and concentration of Zn were 3.61 and 296 mg/kg, respectively in VegBrassica grown in the synthetic soil with 10% (200 g to 2 kg of soil) of added CIGS TFSP, while the BF and concentration of In were 3.80 and 13.72 mg/kg, respectively in VegBrassica grown in the Mollisol, indicating that bioaccumulation occurred. The thermally treated MMWM samples showed morphological transformation mainly on surface based on the scanning electron microscopy (SEM) observations, and an increasing trend in BET specific surface area (SSA) from 120 to 500 ℃ followed by a decreasing trend up to 1000 ℃. Thermal modification had successfully improved Pb adsorption capacity up to 515 mg/g, corresponding to MMWM modified at 600 ℃ with an SSA of 6.5 m2/g. The MO adsorption capacity was also improved after thermal treatment of MMWM, which performed the best adsorption of 87.6 mg/g at 400 ℃. The adsorption of Pb and MO were mainly chemisorption and monolayer coverage, as pseudo-second-order model and Langmuir equation displayed good relationships of correlation for Pb and MO adsorption data. It is therefore indicated that the newly designed soil remediation modules could significantly remove metals from the contaminated soils. In summary, c

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Hendricks, Nicolette Rebecca. "The application of high capacity ion exchange adsorbent material, synthesized from fly ash and acid mine drainage, for the removal of heavy and trace metal from secondary Co-disposal process waters." Thesis, University of the Western Cape, 2005. http://hdl.handle.net/11394/1455.

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In South Africa, being the second largest global coal exporter, coal mining plays a pivotal role in the growth of our economy, as well as supplying our nation’s ever increasing electricity needs; while also accounting for more than 10% of the 20 x 109 m3 water used annually in the country. Coal mining may thus be classified as a large-scale water user; known to inevitably generate wastewater [acid mine drainage (AMD)] and other waste material, including fly ash (FA). Current and conventional AMD treatment technologies include precipitation–aggregation (coagulation/flocculation) – settling as hydroxides or insoluble salts. The process stream resulting from these precipitation processes is still highly saline, therefore has to undergo secondary treatment. The best available desalination techniques include reverse osmosis (RO), electro dialysis (ED), ion exchange and evaporation. All available treatment methods associated with raw AMD and its derived process stream fall prey to numerous drawbacks. The result is that treatment is just as costly as the actual coal extraction. In addition, remediation only slows the problem down, while also having a short lifespan. Research conducted into converting fly ash, an otherwise waste material, into a marketable commodity has shown that direct mixing of known ratios of FA with AMD to a pre-determined pH, erves a dual purpose: the two wastes (AMD and FA) could be neutralized and produced a much cleaner water (secondary co-disposal [FA/AMD]-process water), broadly comparable to the process water derived from precipitation-aggregation treated AMD. The collected post process solid residues on the other hand, could be used for production of high capacity ion exchange material (e.g. zeolite A, faujasite, zeolite P, etc.). The produced ion exchange material can subsequently be utilized for the attenuation of metal species in neutralized FA/AMDprocess waters.
Magister Scientiae - MSc

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Mendes, Marcia Felipe. "Estudo da typha angustifolia l. como material vegetal adsorvente para a remoção dos agrotóxicos trifluralina, clorpirifós e α-endossulfam de meio aquoso." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/6227.

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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
Because of the toxicological relevance of pesticides introduced into the environment through agricultural practices, it is necessary to develop simple methodologies with low cost, enabling remove these pollutants from the environment, in particular of water intended for human consumption. The adsorption process is an efficient and low cost technique that have wide application. The adsorbent capacity of the leaves of Typha angustifolia L. herbaceous perennial plant belonging to the family Typhaceae, in Brazil it is also popularly known as taboa, was investigated for the removal of pesticides trifluralin, chlorpyrifos and α-endosulfan from aqueous medium. The the analytical method using solid phase extraction (SPE) and chromatography with electron capture detector (GC/ECD) was optimizates and validate. The validation criterions were reached and the analytical methos was considered efficient for trifluralin, chlorpyrifos and α-endosulfan quantification in an aqueous medium, providing credibility to the results obtained in the adsorption experiments. The adsorption capacity of T. angustifolia was evaluated under different parameters: treatment of the material, amount of material, contact time between the plant material and the pesticides solution and concentration of the pesticides solution. The results showed that treatment of the material with distilled water and was satisfactory and, for all doses evaluated the pesticide removal was efficient, with best results obtained at a dose of 3.0 g L-1 , equivalent to 60 mg of adsorbent in 20.0 mL of solution, in which the pesticide removal were between 73 and 80%. The adsorption kinetics of the pesticide by T. angustifolia showed that the adsorption equilibrium was reached in 40 minutes for all pesticides, removing up to 90% and using a very small amount of plant material (3 g L-1 ). The experimental data were evaluated using the kinetic models of pseudo-first order, pseudo-second order and Avrami. One of the limitations encountered in the concentration influence study is the limited solubility of the agrochemical in aqueous medium (between 0.33 and 1.00 mg L-1 ), resulting in the study of a small concentration range in the adsorption experiments. To study the pesticides adsorption mechanism by T. angustifolia material, the experimental data were applied to Langmuir, Freundlich and Sips non-linear isotherms models. Additional tests showed that the adsorption capacity is unaffected when using natural water in the adsorption experiments. The results indicate that the material obtained from of T. angustifolia leaves, has a great potential to be used as an alternative adsorbent material in pesticide contaminated aqueous solution treatment.
Devido à relevância toxicológica dos agrotóxicos introduzidos no ambiente através de práticas agrícolas, torna-se necessário o desenvolvimento de metodologias simples e de baixo custo, que permitam remover esses poluentes do meio ambiente, em especial, das águas destinadas a consumo humano. O processo de adsorção é uma técnica que possui grande aplicação, por ser eficiente e de baixo custo. A capacidade adsorvente das folhas de Typha angustifolia L., planta herbácea perene pertencente à família Typhaceae, no Brasil também conhecida popularmente como taboa, foi investigada para a remoção dos agrotóxicos trifluralina, clorpirifós e α-endossulfam de meio aquoso. Foi realizada a otimização e validação da metodologia analítica de extração em fase sólida (SPE) e determinação por cromatografia gasosa utilizando-se o detector por captura de elétrons (GC/ECD). A metodologia (SPEGC/ECD) atendeu aos critérios de validação estabelecidos e foi eficiente para a quantificação dos agrotóxicos em meio aquoso, fornecendo credibilidade aos resultados obtidos nos ensaios de adsorção. A capacidade de adsorção da T. angustifolia foi avaliada sob diferentes parâmetros: tratamento do material, dose de material, tempo de contato entre o material vegetal e a solução dos agrotóxicos e concentração dos agrotóxicos na solução. Os resultados obtidos mostraram que o tratamento do material com água destilada foi satisfatório e que para todas as doses de adsorvente avaliadas a remoção dos agrotóxicos foi eficiente, sendo obtido um melhor resultado para a dose de 3,0 g L-1 , equivalente a 60 mg de adsorvente para 20,00 mL de solução, onde se obteve remoção entre 73 e 80% dos agrotóxicos. O estudo cinético do processo de adsorção dos agrotóxicos pela T. angustifolia mostrou que o equilíbrio de adsorção foi alcançado em 40 minutos, para todos os agrotóxicos, com remoção de até 90%, utilizando uma dose muito pequena de material vegetal (3 g L-1 ). Os dados experimentais foram avaliados utilizando-se os modelos cinéticos de pseudo-primeira ordem, pseudo-segunda ordem e Avrami. Uma das limitações encontradas no estudo da influência da concentração foi a solubilidade limitada dos agrotóxicos em meio aquoso (entre 0,33 e 1,00 mg L-1 ), que fez com que os ensaios de adsorção fossem avaliados para uma pequena faixa de concentração. Para estudar o mecanismo de adsorção dos agrotóxicos pelo material T. angustifolia, os dados experimentais foram aplicados aos modelos não lineares de Langmuir, Freundlich e Sips. Ensaios adicionais mostraram que a capacidade de adsorção é pouco afetada quando se utiliza água natural obtida em represas nos ensaios de adsorção. Os resultados obtidos indicam que o material vegetal, obtido a partir das folhas de T. angustifolia, possui um grande potencial para ser utilizado como material adsorvente alternativo no tratamento de meio aquoso contaminado com os agrotóxicos trifluralina, clorpirifós e α-endossulfam.

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Carpentier, Pascal. "Etude de la sorption des oxydes de soufre par des masses regenerables a base d'oxyde de magnesium." Paris 6, 1987. http://www.theses.fr/1987PA066296.

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L'adsorption des oxydes de soufre par des masses regenerables a ete etudiee. Ces travaux s'inscrivent dans le cadre de la mise au point d'un procede de desulfuration de divers effluents de raffineries petrolieres sur une masse composee de 30% d'oxyde de magnesium associe a de l'alumine et dopee par 50 ppm de platine

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Behra, Philippe. "Etude du comportement d'un micropolluant metallique (le mercure) au cours de sa migration a travers un milieu poreux sature : identification experimentale des mecanismes d'echanges et modelisation des phenomenes." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13120.

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López-Aranguren, Oliver Pedro. "Functionalized adsorbent materials using supercritical CO2." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/284975.

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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.

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Mignard, Samuel. "Mode de désactivation des zéolithes : caractérisation des zéolithes cokées par adsorption de diverses molécules." Poitiers, 1988. http://www.theses.fr/1988POIT2297.

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12

Pakulski, Dawid. "Graphene based materials and their potential applications." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF060.

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Cette thèse de doctorat a pour objectif scientifique la synthèse de matériaux bidimensionnels fonctionnalisés (graphène et oxyde de graphène) et leur caractérisation physicochimique complète, avec un accent particulier apporté sur les propriétés d'adsorption et de stockage d'énergie. Nous avons démontré que la modification covalente de l'oxyde de graphène (GO) avec un polymère organique (BPEI) affecte très favorablement l'efficacité du processus d'adsorption. Les valeurs de la capacité maximale d'adsorption (qmax) des ions de métaux lourds favorisent de manière significative ce matériau par rapport à la majorité des adsorbants connus à base de carbone. En outre la fonctionnalisation de GO avec l'aminosilicate mésoporeuse (SiO2NH2) conduit à l'obtention d'un adsorbant efficace et rapide des colorants organiques cationiques (MB, RhB, MV). En plus nous avons prouvé que la fonctionnalisation du graphène (EEG), en utilisant les sous-unités de surfactant POM, a montré que ce type de matériau hybride organique-inorganique est très stable et présente des propriétés électriques intéressantes pouvant être utilisées dans la production de supercondensateurs
Scientific purpose of this doctoral dissertation is synthesis of functionalized two-dimensional materials (graphene and graphene oxide) and their comprehensive physicochemical characterization, with particular emphasis on adsorption and energy storage properties. We could demonstrate that covalent modification of graphene oxide (GO) with an organic polymer (BPEI) very favorably affects the efficiency of the adsorption process. The maximum adsorption capacity (qmax) values for heavy metal ions significantly favour this material in comparison to the majority of known carbon adsorbents. Moreover, functionalization of GO with mesoporous aminosilica (SiO2NH2) leads to obtaining an efficient and rapid adsorbent of organic cationic dyes (MB, RhB, MV). ln addition we proved that the functionalization of graphene (EEG) using the POM-surfactant su bu nits proved that this type of organic-inorganic hybrids material is very stable and have interesting electrical properties with potential application in the production of supercapacitors

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13

Mokaya, Robert. "Layered materials as selective adsorbents." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260454.

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14

Purvis, Duncan Ross. "Perfluoropolymer adsorbents." Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/273023.

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15

ABDALLAH, KHODR. "Contribution experimentale a l'etude de la cinetique d'adsorption de gaz." Paris, ENSAM, 1989. http://www.theses.fr/1989ENAM0003.

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Une nouvelle technique experimentale a ete mise au point pour etudier la cinetique d'adsorption due aux transferts de masse et de chaleur. Application a l'adsorption du methanol sur la zeolite x et le charbon actif

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16

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.

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17

Ogbuka, Chidi Premie. "Development of solid adsorbent materials for CO₂capture." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13276/.

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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).

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18

Doi, Shinichi. "Novel starch materials for adsorbents and catalysts." Thesis, University of York, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434057.

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19

Didas, Stephanie Ann. "Structural properties of aminosilica materials for CO₂ capture." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54020.

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Increased levels of carbon dioxide in the atmosphere are now widely attributed as a leading cause for global climate change. As such, research efforts into the capture and sequestration of CO2 from large point sources (flue gas capture) as well as the ambient atmosphere (air capture) are gaining increased popularity and importance. Supported amine materials have emerged as a promising class of materials for these applications. However, more fundamental research is needed before these materials can be used in a practically relevant process. The following areas are considered critical research needs for these materials: (i) process design, (ii) material stability, (iii) kinetics of adsorption and desorption, (iv) improved sorbent adsorption efficiency and (v) understanding the effects of water on sorbent adsorption behavior. The aim of the studies presented in this thesis is to further the scientific community’s understanding of supported amine adsorbents with respect to stability, adsorption efficiency and adsorption behavior with water.

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20

Al-Mousawi, Fadhel. "Adsorption system for cooling and power generation using advanced adsorbent materials." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8641/.

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This thesis investigates the feasibility of producing electricity and cooling simultaneously utilising low-grade heat sources by incorporating an expander within the adsorption cooling system or by integrating an Organic Rankine Cycle with water adsorption cooling system. Advanced physical adsorbent materials have been investigated for the first time to generate cooling and electricity simultaneously utilising CPO-27(Ni), MIL101(Cr), and AQSOA-Z02 and compared to commonly used Silica-gel. Two innovative configurations of water adsorption systems for cooling and electricity were investigated. In the first configuration, the two-bed basic adsorption cooling system (BACS) is improved by including an expander within the system. In the second configuration, the BACS and ORC cycle are integrated. Four different scenarios of systems integration based on the way of powering the ORC and the adsorption system were investigated. Also, detailed CFD simulations of small-scale radial inflow turbines are developed for both configurations. Also, a novel experimental facility is developed to integrate ORC with two-bed adsorption cooling system to validate the numerical models and proof the concept of producing power as well as cooling, where maximum specific cooling power of 252 W/kgads and specific power and of 162 W/kgads can be achieved with maximum deviation of less than 17%.

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21

Holyfield, Leighton. "Materials based on the polymer of intrinsic microporosity PIM-1 for hydrogen storage applications." Thesis, University of Bath, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760988.

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In response to the ever-increasing global energy demand and the need to move away from non-renewable and CO2-emitting fossil fuels as the primary energy production method, renewable energy sources have become more and more viable as energy production methods. However, given the unreliable and instantaneous nature of these energy sources, reliable, renewable energy storage methods are required. Hydrogen is an excellent candidate as a chemical energy store, as it is highly abundant, relatively easily produced as diatomic hydrogen (including from water electrolysis), and only produces water upon its complete combustion. Hydrogen also has the highest gravimetric energy density of any known chemical fuel, meaning that not very much of it is required relative to other chemical fuels. However, hydrogen gas is incredibly sparse, and therefore hydrogen has a very low volumetric energy density, making storage of the material a key challenge in the development of the so-called “hydrogen economy”. Most commonly, hydrogen is stored by compressing it to 70 MPa. However, this technique has a number of flaws, including the high expense of strong tanks (and in the case of light duty vehicles, lightweight materials are also required), and the inherent safety risks that high pressure, highly flammable gas poses. One of the alternatives to compression is to store hydrogen by adsorption, which uses high surface area materials to densify hydrogen via the formation of weak physical bonds. This research line is well developed, and a number of different materials has been created that show good potential as hydrogen storage materials, such as activated carbons and metal organic frameworks. However, the vast majority of materials developed for this purpose are tailored only with the hydrogen uptake in mind, which can cause issues as the focus of development shifts from small scale tests to full tank scale. One adsorptive that shows a number of highly useful engineering properties on the large scale, such as good thermal resistance and solution processability, is the polymer of intrinsic microporosity PIM-1. This material can be processed into a number of morphologies without losing porosity, and shows good thermal and mechanical resistance. However, its adsorption capacity is rather limited, with the BET surface area generally reported in the 700 – 800 m2 g-1 range, and hydrogen uptake of 1.45 wt% at 77 K and 1 MPa. This thesis presents two separate studies on attempting to improve the hydrogen uptake of PIM-1 without adversely affecting the material properties that make it attractive. The first of these was the creation of mixed-matrix-membrane style composite films solution cast from PIM-1 and the metal organic framework MIL-101. PIM-1 proved slightly difficult to synthesise consistently with high molecular weight, but MIL-101 is an easy hydrothermal synthesis. Film casting was successfully performed, producing flat, homogeneous films that maintained the MOF crystallinity. These materials were tested for their thermal properties – thermal decompositions proceeded according to the rule of mixtures of the two starting materials, whilst an increasing concentration of MOF was shown to decrease the specific heat capacity. Both PIM-1 and MIL-101 were shown to adsorb nitrogen as previously reported. The composites showed increasing uptake with MIL-101 content, but at a lower rate than the rule of mixtures. This was a common theme for the N2 (77 K), CO2 (293 K) and low pressure H2 isotherms performed. High pressure isotherms up to 17 MPa were performed on PIM-1 for the first time, showing a maximum excess uptake of 1.8 wt% on the powder and 1.6 wt% on the film, both at 77 K. The composites showed improved uptake with increasing MIL-101, but the maximum uptakes did not meet the rule of mixtures. The uptakes at the highest pressure did, however. Multiple temperature isotherm sets were performed on the PIM-1 film and powder, as well as the 30 wt% composite. These data sets were hampered largely by machine faults, but contained sufficient valuable data to be able to proceed with parameter fitting. The sensitivity of the isotherms produced in this study to the value of skeletal density is also examined closely. The second theme of improved H2 uptake in PIM-1 was to carbonise the material. TGA studies on PIM-1 showed good thermal stability in anoxic conditions, and TGA twinned with mass spectroscopy was able to confirm a previously proposed mechanism of thermal decomposition. Carbonised and activated PIM-1 film samples, and a carbonised powder, were produced using physical activation methods. The adsorption performance of the carbons was disappointing, as the uptakes of N2 and H2 (< 0.1 MPa) were reduced post-carbonisation, with little recovery in the activated film. CO2 uptakes were improved, however. High pressure H2 isotherms on both the carbonised and activated films showed unusual ‘stepping’ behaviour in the adsorption curve, but maximum uptakes for both (1.0 – 1.3 wt%) were less than that seen for PIM-1 alone. Parameter fitting was performed on all of the high pressure H2 isotherms performed in this study, using a method previously proposed by the Mays group. The parameter fits all showed effective hydrogen densification in the adsorbate layer, although the repeatability of parameter values, and the smoothness of the parameters as a function of temperature were undermined by the low quality of some of the isotherms. Using the parameters acquired, it was possible to calculate the isosteric enthalpy of adsorption for PIM-1 powder (-9.5 kJ mol-1), film (- 8.0 kJ mol-1) and the 30 wt% composite (-9.3 kJ mol-1). The stored and deliverable hydrogen contained within tanks featuring the tested materials were estimated, although only the MIL-101 powder on its own competes with other hydrogen storage adsorbents currently reported.

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22

Bollini, Praveen P. "Amine-oxide adsorbents for post-combustion CO₂ capture." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52908.

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Amine functionalized silicas are promising chemisorbent materials for post-combustion CO₂ capture due to the high density of active sites per unit mass of adsorbent that can be obtained by tuning the synthesis protocol, thus resulting in high equilibrium CO₂ adsorption capacities. However, when compared to physisorbents, they have a few disadvantages. Firstly, oxidative degradation of the amine groups reduces the lifetime of these adsorbent materials. Furthermore, rapid heat release following the reaction between amines and CO₂ results in large local temperature spikes which may adversely affect adsorption equilibria and kinetics. Thirdly, there is a lack of fundamental understanding of CO₂-amine adsorption thermodynamics, which is key to scaling up these materials to an industrial-scale adsorption process. In this dissertation the qualitative and quantitative understanding of these three critical aspects of aminosilica adsorbents have been furthered so these materials can be better evaluated and further tuned as adsorbents for post-combustion CO₂ capture applications.

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23

CUCCARESE, MARCO. "“Development and characterization of innovative adsorbent materials for the remediation of contaminated water”." Doctoral thesis, Università degli studi della Basilicata, 2021. http://hdl.handle.net/11563/147019.

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The present thesis deeply investigated the use of a commercial innovative material, the thermoplasma-expanded graphite (TPEG), as adsorbent material for water remediation. This innovative material has never been used for this kind of applications and this thesis would demonstrate its effective use for water and groudwater remediation. TPEG is a promising material for that purpose due to its characteristics, evidenced by the producer, such as: high surface area and very significative expansion of interlayer distance of the plan of graphite. The commercial form of the TPEG is a very light powder that floats on the water, therefore, it was used in its natural form in batch tests. Adsorption of different pollutants, such as methylene blue, thricloethylene and diclofenac, was deeply investigated by evaluating the kinetics and isothermal aspect of the adsorption. Furthermore, other parameters that can affect the adsorption, such as pH, initial concentration of pollutants, ionic strength or presence of interference, were investigated. The possibility of regenerating and reusing the TPEG as adsorbent was also evaluated. Modification of the morphology of TPEG was conducted in order to use it as adsorbent material for different setup of process, like fixed-bed column. To this aim, the commercial form was transformed into a granular form of thermo-plasma expanded graphite (GTPEG), by entrapping TPEG into calcium alginate, by using a process that was developed and optimized during tihis thesis work. The GTPEG was then used to treat water by adsorption on fixed bed column. The process was deeply investigated and several pollutants were tested as target compounds, such as short chain phthalates (plasticizers), carbamazepine, bisphenol, 1,7-α ethynilestradiol and atrazine. The effect of adsorbent dosage, flow rate, initial concentration of pollutants, time contact and composition of GTPEG was evaluated. Other tests were conducted to verify the leaching of GTPEG. Adams-Bohart and Thomas models can effective applied to modelize the process and to evaluate its scale up. A sonication process was optimised to transform the not soluble TPEG into a hydrosoluble form, useful to treat groundwater by injecting the adsorbent material to obtain a hydraulic barrier able to contain and remove the pollution. By using this hydrosoluble form, TPEG can be used as material for the installation of injectable permeable reactive barrier. The capacity of the hydrosoluble TPEG to adsorb BTEX was firstly tested and characterized by using the batch setup to have all the information on the adsorption process. After the deeply characterization of the adsorption process, the use as injectable permeable reactive barrier to remove BTEX from groundwater was investigated. Innovative commercial materials can be used as adsorbent, but waste materials also represent a source of adsorbent materials. For this reason, a little part of the thesis was reserved to this kind of work. The last chapter reports a study conducted on the reuse of agricultural-food waste as adsorbent material: the spent ground coffee. The ability of spent ground coffee as adsorbent material was demonstrated by deeply investigating its capability to remove methylene blue.

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24

Lotsi, Bertha. "Mesoporous Adsorbents for Perfluorinated Compounds." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/etd/3729.

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Effective adsorbents for polyfluorinated compounds (PFCs) were successfully prepared. And they were tested in the adsorption of perfluorooctanoic and perfluorooctanesulfonic acids. Bridged silsesquioxanes containing secondary and tertiary amino groups were synthesized by sol-gel condensation of bis[3-(trimethoxysilyl)propyl]amine and bis[3-(methylamino)propyl]-trimethoxysilane in acidic media with surfactants. Obtained materials are mesoporous with a high BET surface area. They combine high structural stability with a high concentration of surface amino groups serving as adsorption sites. Batch adsorption tests demonstrated their extremely high adsorption capacity on PFCs: in some experiments, it reached up to 88% of the adsorbent weight. Adsorption of PFCs changed the surfaces of the adsorbent nanoparticles from hydrophilic to hydrophobic thus providing their agglomeration and floatability. Column tests showed fast adsorption of PFCs even at high concentrations and high flow rates. Obtained results can be used in the development of an effective filtration device for clean-up of water contaminated by PFCs.

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25

LEAL, ROBERTO. "Estudo da magnetita como material adsorvedor de íons uranilo." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9299.

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Made available in DSpace on 2014-10-09T12:25:53Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:00:29Z (GMT). No. of bitstreams: 0
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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26

Bergamini, Rajeriarisaona Théo. "Mise au point de gels pour la chromatographie d'affinite d'un cytochrome p-450 : la cinnamate-4 hydroxylase." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13164.

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Les proprietes selectives et specifiques des substrats ont ete exploitees pour purifier une enzyme vegetale: la cinnamate-4 hydroxylase localisee dans les microsomes des tubercules de topinambour. Cinq supports a base d'agarose ont ete prepares. Ils ont ete modifies par l'acide transhydroxycinnamique. Ils se differencient les uns des autres par la structure chimique et la longueur de bras. L'efficacite de ces gels en chromatographie d'affinite a ete testee. Une fraction enrichie en ca4h presente par electrophorese une bande vers 56 000 daltons caracteristique des cytochromes p 450. Une autre matrice susceptible de supporter les pressions elevees a ete synthetisee. Elle est a base de silice enrobee par un alcool polyvinylique prealablement modifie. Elle a permis d'acceder a un taux de greffage superieur a ceux obtenus sur l'agarose. Ce gel a permis, comme le precedent, la separation par chromatographie d'affinite du cytochrome p 450. Ce support chromatographique a le merite supplementaire de resister a la pression

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27

Honma, Sensho. "Production of aromatic compounds and functional carbon materials by pulse current pyrolysis of woody biomass." Kyoto University, 2015. http://hdl.handle.net/2433/200459.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第19196号
農博第2135号
新制||農||1034(附属図書館)
学位論文||H27||N4942(農学部図書室)
32188
京都大学大学院農学研究科森林科学専攻
(主査)教授吉村剛, 教授髙野俊幸, 教授渡邊隆司
学位規則第4条第1項該当

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28

Wang, Jiabin. "Synthesis of graphene based materials and other applications as energy storage materials and Ni (II) ions adsorbant." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3748.

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Today, with the increasing global concern regarding energy savings, CO2 emission and environmental protection, the development of low cost and environmentally friendly materials for electrodes in energy storage devices and adsorbent in wastewater treatment becomes important. Graphene, as a new materials, has attracted lots of attention due to its high current carrying capacity and high surface area. These properties give graphene the huge potential to be used as electrode materials for energy storage devices and adsorbant materials for heavy metal ions. However, the complicate synthesis methods and long reaction time limit its industrial scale up application. In this thesis, the research is focused on development of graphene based composite materials produced by fast, green and energy saving synthesis methods and study their usage as electrodes and for Ni (II) ions removal by analysing the electrochemical properties and Ni (II) ions absorb capacity. Beside graphene, bismuth has also been considered as safe and non-toxic material. In addition, a large amount of bismuth is produced as a by-product of the copper and tin refining industry. The long Fermi wavelength and high Hall coefficient give bismuth the possibility to reach high electronic conductivity with controlled structure. Therefore, bismuth compounds were selected to decorate graphene for the electrode materials. In this study, reduced graphene oxide bismuth composite (rGO/Bi, Bi2O3-GO, rGO/Bi2O2CO3) were synthesis at 60 C or room temperature with short reaction time of 3 hrs. These composite materials exhibit nano-structure and good electrochemical properties, such as high specific capacity and long cycling life. In the rGO/Bi composite materials, bismuth particles with size around 20 to 50 nm were wrapped and protected by graphene layers from oxidation. This composite materials achieves a specific capacity value of 773 C g-1, which is in the range of its theoretical value. In the Bi2O3-GO composite material, Bi2O3 shows a flower-like shape and linked by graphene oxide layer. This material reaches a specific capacity value as high as 559 C g-1. In the rGO/Bi2O2CO3 composite materials, nanosized bismuth subcarbonate were attached on the graphene layers. This composite material shows stable cycling performance even afi ter 4500 cycles. With the low cost of initial materials, simple synthesis methods, low reaction temperature, short reaction time, high specific capacity value and stable long cycling life, graphene bismuth compounds could be the promising candidates for the future electrodes used in electrochemical energy storage devices. The ability of Ni (II) ions removal by graphene oxide (GO) with sodium dodecyl sulphate (SDS) was also studied. Previous studies have proved that Ni is an excellent catalyst for carbon dioxide reforming. A robust Ni (II) ions removal absorbant is needed in order for this technology to become widely acceptable. SDS has been widely used as the industrial surfactant in toothpaste and shampoo. By adding SDS to decorate GO, it helps prevent graphene oxide sheets from stacking back together and then further enlarge the GO’s capacity of Ni (II) ions removal. In this work, SDS was added to modify graphene oxide surface by a one-step easy-to-handle method at room temperature. The effect of time on adsorption, initial concentration of Ni (II) ions and pH value of the Ni (II) ion solutions with GO and GO-SDS were analyzed. The driving force of the adsorption of Ni (II) ions on GO-SDS is proved to be by electrostatic attraction, Ni (II) ions are adsorbed on the GO surface chemically and by ion exchange. By using SDS modified GO, the Ni (II) ions adsorption capacity was increased dramatically from 20.19 mg g-1 to 55.16 mg g-1 in respect to pure GO.

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29

Camacho, Bárbara Cassiana Rodrigues. "Experimental Gravimetric Adsorption Equilibrium of n-Alkanes and Alkenes, Carbon Dioxide and Nitrogen in MIL-53(Al) and Zeolite 5A." Master's thesis, Faculdade de Ciências e Tecnologia, 2014. http://hdl.handle.net/10362/12140.

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Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica
The objective of this work was the measuring of adsorption equilibrium, by the gravimetric method. Experimental results are presented for the adsorption equilibrium of the series of n-alkanes, ethylene, nitrogen and carbon dioxide in two microporous materials, the metal-organic framework, MIL-53(Al) and zeolite 5A. Both of them have desirable characteristics for adsorption processes, such as the capture and storage of carbon dioxide, natural gas storage, separation of components of biogas, and separation of olefin/paraffin. The determination of the equilibrium of the pure components (ethane, propane, butane, ethylene, carbon dioxide and nitrogen) covers a wide range of thermodynamic conditions; temperatures between 303.15K and 373.15K, as well as pressure values between 0 and 50 bar. The adsorption equilibrium data were analyzed through the global adjustment for each adsorbate/adsorbent system, using the Sips and Toth models. The isosteric heat was also determined. The experimental data of methane, carbon dioxide and nitrogen were correlated successfully by the potential theory of adsorption collapsing into a single characteristic curve, independent of temperature. This analysis allows the extrapolation of adsorption data for other gases, for which no experimental data is still known. The adsorption capacity is generally higher in MIL-53(Al) than in zeolite 5A, and in the two adsorbents, the preferred adsorption capacity for carbon dioxide is a good indication that these materials have a strong potential in the capture and storage of carbon dioxide, in the purification of biogas or purification of methane from natural gas.

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30

Eggeling, Joachim. "Inelastic electron scattering from adsorbate covered semiconductor surfaces." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313773.

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31

Guiu, Julien 1974. "Synthesis of hydroxyapatite with adsorbed and intracrystalline biomolecules." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85322.

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32

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.

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33

Chgoura, Mohammed. "Adsorption par des charbons actifs de molécules organiques à partir de solutions aqueuses." Aix-Marseille 1, 1987. http://www.theses.fr/1987AIX11082.

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34

Leal, Roberto. "Estudo da magnetita como material adsorvedor de íons uranilo." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-15052012-132433/.

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A magnetita, também chamada de ferrita de ferro, é um minério conhecido como imã natural e encontrada em depósitos de ferro. Além desse comportamento intrínseco, a magnetita possui a capacidade de remover os íons metálicos do meio aquoso por fenômenos de adsorção. O seu caráter fortemente magnético a distingue de outros tipos de adsorventes, visto que, é facilmente removida da solução por separação magnética. Neste trabalho estudou-se a adsorção de urânio(VI), na forma de íons UO22+, de solução nítrica pela magnetita sintética. Esta foi preparada por precipitação simultânea adicionando-se uma solução de NaOH à solução contendo os íons Fe2+ e Fe3+. A magnetita sintética, na forma de um pó preto, exibiu uma resposta magnética de atração intensa na presença de um campo magnético, sem contudo tornar-se magnética, um comportamento típico de material superparamagnético constatado por medidas de magnetização. Estudou-se a influência dos parâmetros de adsorção de íons UO22+ tais como o pH, a dose do adsorvente, tempo de contato e a isoterma de equilíbrio. A máxima adsorção de urânio foi encontrada no intervalo de pH entre 4 e 5. Verificou-se que quanto maior a dose de magnetita menor a capacidade de adsorção e maior a remoção de U. Da relação entre adsorção e tempo de contato verificou-se que a remoção aumentou rapidamente com o tempo e atingiu-se a condição de equilíbrio em 30 min. Os resultados da isoterma de equilíbrio apresentaram maior concordância com o modelo de Langmuir, o qual permitiu a determinação da capacidade teórica de saturação da magnetita para o urânio. A interação entre os íons UO22+ e a magnetita foi caracterizada como uma adsorção química e espontânea.
Magnetite, also known as iron ferrite, is a mineral iron and a natural magnet found in iron deposits. In addition to its magnetic intrinsic behavior, the magnetite has the capacity to remove the metallic ions from aqueous medium by adsorption phenomena. The strong magnetic character of magnetite distinguishes it from other adsorbent types, which it allows to be readily removed from solution by magnetic separation. In this work, uranium (VI) adsorption, as UO22+ ions, from nitric solution by synthetic magnetite was investigated. It was prepared by simultaneous precipitation process, adding a NaOH solution into a solution containing Fe2+ and Fe3+ ions. The synthetic magnetite, a black powder, has exhibited a strong magnetic response in presence of a magnetic field, without nevertheless becomes magnetic. This typical superparamagnetic behavior was confirmed by magnetization measurements. Adsorption parameters of UO22+ ions such as pH. the adsorbent dose, contact time and equilibrium isotherm were evaluated. Maximum uranium adsorption was observed in the pH 4.0-5.0 range. It was noticed that increase in magnetite dose increased the percent removal of uranium, but decreased the adsorption capacity of the magnetite. It was observed from the relation between adsorption and contact time that the removal has increased very fast with time, and achieved the equilibrium within 30 minutes. The results of equilibrium isotherm agreed well with the Langmuir model, and so the theorical saturation capacity of the magnetite was determined for uranyl ions. The interaction between UO22+ ions and the magnetite was defined as a spontaneous chemical adsorption.

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Kavi, Parthiv. "The preparation and characterisation of highly selective adsorbents for fission product removal from acid solutions." Thesis, University of Central Lancashire, 2016. http://clok.uclan.ac.uk/16576/.

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Nuclear fuel reprocessing of fissile materials is carried out in order to provide recycled fuel for existing and future nuclear power plants. One aim of reprocessing is to recover unused uranium (U-238 and U-235) and plutonium isotopes thereby preventing them from being wasted. This can save up to 30% of the natural uranium that is required each year for the fabrication of new nuclear fuel. A second aim is to reduce the volume of high-level radioactive waste. Along with the separation of uranium and plutonium there has been a significant interest in the extraction of short-lived fission products such as caesium and strontium, which play critical role during high-level waste handling and disposal. The PUREX process for reprocessing of irradiated fuel has been unchallenged for more than half a century even though it has several deficiencies such as flexibility, non-specificity of Tri-Butyl Phosphate (TBP), degradation of the extractant, TBP, and diluent. This project addresses the development of an alternative separation process to either replace and/or complement the PUREX process. Our process is based on the chromatographic separation of fission products from U and Pu. This research focuses on the synthesis of highly stable and selective materials which could be used as a stationary phase in a continuous chromatographic separation for short lived fission products (Cs, Sr); a technique patented by UCLan. The objectives of this project were to synthesis highly selective adsorbents for fission products (primarily Cs and Sr) capable of extracting these cations from acidic liquor (up to 3 M HNO3). In addition to selectivity (specificity) and acid stability, the materials under investigation would require fast cation uptake and high capacity. The research explored three key approaches for ion sorption: (1) Creating charge imbalance into ordered mesoporous MCM-41 structure (chapter 4), (2) Examination of molecular sieves based on their size exclusive property (chapter 5), and, (3) Preparation of ammonium phosphomolybdate (AMP) encapsulated polymeric composites (chapter 6). Various physical and chemical properties of the materials were characterised by XRD, SAXS, surface area, pore volume, pore size distribution, SEM, TEM, ATR-IR, 29Si NMR and TGA techniques. The cation uptake performance of the materials were evaluated for single ion and mixed ions against various nitric acid conditions. The study was further extended to rate of uptake in the best performing AMPPAN composites and identified area of improvement. Insertion of heteroatom e.g. boron into silicate structures, did not produce the desired effect; selectivity and capacity for the target fission products (Cs and Sr) were negligible compared with the required criteria. The incorporation of a mesoporous shell around zeolite structure was effective but the uptake of fission products from nitric acid solutions was again disappointing. The uptake of fission products from slightly acid solutions (pH value ~5) was more encouraging but not specific to any single ion (e.g. Cs or Sr) and this approach could form the basis of further studies. The preparation of AMP composites addressed both inorganic and organic substrates; AMP alumina composites in a suitable form i.e. spheres/beads was challenging and produced materials that were unsuitable and incorporated low AMP concentrations. This produced composites with low Cs uptake. The use of an organic substrate such as polyacrylonitrile (PAN) produced a composite that had a high selectivity for Cs, near specific, from nitric acid solutions but with comparatively low capacity and rate of uptake compared to pure AMP. These properties could be improved by manipulation of the composite structure; future work in this area is recommended.

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Baur, Jeffery W. (Jeffery Wayne). "Fabrication and structural studies of sequentially adsorbed polyelectrolyte multilayers." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10424.

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Mallmann, Aimery de. "Modifications du benzène par adsorption sur des faujasites échangées par des ions alcalins." Paris 6, 1986. http://www.theses.fr/1986PA066347.

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L'évolution du spectre infrarouge du benzène adsorbe sur des faujasites est suivie en fonction de la composition chimique des adsorbants (zéolites désaluminées, zéolite y ou x, zéolites modifiées par des ions Na, Rb, etc) et de la quantité de benzène adsorbé. On note que 4 formes de benzène ont été mises en évidence, dont l'une est faiblement fixée sur les solides.

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Gutierrez, Angela. "DEVELOPMENT OF MAGNETIC NANOCOMPOSITE MATERIALS AS REUSABLE ADSORBENTS FOR CHLORINATED ORGANICS IN CONTAMINATED WATER." UKnowledge, 2019. https://uknowledge.uky.edu/cme_etds/107.

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The constant growth in population worldwide over the past decades continues to put forward the need to provide access to safe, clean water to meet human needs. There is a need for cost-effective technologies for water and wastewater treatment that can meet the global demands and the rigorous water quality standards and at the same maximizing pollutant efficiency removal. Current remediation technologies have failed in keeping up with these factors without becoming cost-prohibitive. Nanotechnology has recently been sought as a promising option to achieve these goals. The use of iron oxide magnetic nanoparticles as nanoadsorbents has led to a new class of magnetic separation strategies for water treatment. We have developed magnetic nanocomposite systems able to capture polychlorinated biphenyls (PCBs), as model organic pollutants, in aqueous solution, providing a cost-effective water remediation technique. Two distinct methods were employed to develop these polyphenolic nanocomposite materials. The polyphenolic moieties were incorporated to create high affinity binding sites for organic pollutants within the nanocomposites. The first method utilized a surface initiated polymerization of polyphenolic-based crosslinkers and co-monomers on the surface of iron oxide magnetic nanoparticles to create a core-shell nanocomposite. The second method utilized a bulk polymerization method to create macroscale films composed of iron oxide nanoparticles incorporated into a polyphenolic-based polymer matrix, which were then processed into microparticles. Both methods produce nanocomposite materials that can bind chlorinated organics, can rapidly separate bound organics from contaminated water sources using magnetic decantation, and can use thermal destabilization of the polymer matrix for contaminant release and material regeneration. The polyphenol functionalities used to bind organic pollutants were quercetin multiacrylate (QMA) and curcumin multiacrylate (CMA), which are acrylated forms of the nutrient polyphenols quercetin (found in berries) and curcumin (found in turmeric), both with expected affinity for chlorinated organics. The affinity of these novel materials for PCB 126 was evaluated at equilibrium conditions using a gas chromatography coupled to electron capture detection (GC-ECD) for quantification purposes, and the data was fitted to the nonlinear Langmuir model to determine binding affinity (KD) and maximum biding capacity (Bmax). The KD values obtained demonstrated that the presence of the polyphenolic-based moieties, CMA and QMA, as crosslinkers enhanced the binding affinity for PCB 126, expected to be a result of their aromatic rich nature which provides sites for π – π stacking interactions between the nanoparticle surface and the PCBs in solution. These values are lower that the reported affinity coefficients for activated carbon, which is the gold standard for capture/binding of organic contaminants in water and waste water treatment. Furthermore, upon exposure to an alternating magnetic field (AMF) for a period of 5 minutes, over 90% of the bound PCB on these materials was released, offering a low-cost regeneration method for the nanocomposites. Additionally, this novel regeneration strategy does not require the use of large volumes of harsh organic solvents that oftentimes become harmful byproducts. Overall, we have provided strong evidence that these novel nanocomposites have a promising application as nanoadsorbents for specific organic contaminants in contaminated water sources providing high binding affinities, a low-cost regeneration technique and are capable of withstanding use under environmental conditions offering a cost effective alternative to current remediation approaches.

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39

Quispe, Mitma Eida Agripina. "Utilización de cáscara de plátano como material adsorbente en la remoción de fosfato en solución acuosa." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2021. https://hdl.handle.net/20.500.12672/17819.

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Evalúa la remoción de fosfatos por un adsorbente elaborado a partir de cáscara de plátano de la variedad Bellaco a diferentes temperaturas de pirólisis y pH en solución acuosa. La cáscara de plátano de la variedad Bellaco de procedencia de Satipo se sometió a distintos tratamientos de carbonización a temperaturas de 500 ºC, 600 ºC y 700 ºC (P500, P600 y P700). Los adsorbentes se sometieron a experimentos de adsorción por lotes a distintos pH; en este proceso se elaboró una solución acuosa de 0,3 mg/L de fosfato, ajustando a pH de 4,0; 7,0 y 10,0 y se agregó el material adsorbente en una concentración de 1 g/L, se dejó reposando con agitación ocasional durante 168 horas a temperatura ambiente (23 °C en promedio). El fosfato al inicio del tratamiento y al término del tratamiento se cuantificó mediante espectrofotometría uv-visible. El adsorbente mostró la capacidad de remoción de fosfatos a pH 7 y 10, sin embargo, hubo liberación de fosfatos a pH 4. Los datos cinéticos se describieron con éxito mediante el modelamiento de difusión intraparticular, seguido por el de pseudo-segundo orden. El tratamiento P500 presentó mayor capacidad de remoción de fosfatos (92,1 %) a pH 10. La producción de adsorbente se presenta como una alternativa sostenible a partir del aprovechamiento residuos de la industria de los chifles (snack de plátano), en el marco de una economía circular
Perú. Universidad Nacional Mayor de San Marcos. Vicerrectorado de Investigación y Posgrado. Programa de Promoción de Tesis de Pregrado. E18030044-PTPGRADO.

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Hassen, J. H. "Spectroscopic analysis of adsorbed macrocyclic complexes on ceramic and related materials." Thesis, University of Essex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481601.

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41

Alorkpa, Esther. "Development of Granulated Adsorbent for Clean-up of Water contaminated by Cesium." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etd/3558.

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A study was conducted on sol-gel synthesis of an adsorbent (phosphotungstic acid embedded in silica gel, H-PTA/SiO2) of radioactive cesium. A novelty of this work is covalent bonding of PTA to the surface of solid support that prevents leaching from the surface of the material. The sample was granulated with a binder, aluminium oxide (γ-Al2O3). Solid-state NMR and FT-IR spectroscopy were used to confirm the presence of Keggin units of PTA in the bound materials. Thermal analysis of H-PTA/SiO2 - γ-Al2O3 (50 %) showed that the water content in the bound material was appreciably lower than in the pure adsorbent. Quantitative determination of surface acidity of porous materials is an important analytical problem in characterization of the adsorbents. This problem was solved by reversed titration after saturation of the materials by anhydrous solution of pyridine. Batch and column adsorption tests showed that the adsorbent demonstrated high adsorption capacities towards cesium.

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Sun, Xin. "Organofunctional silica mesostructures with improved accessibility and applications as heavy metal ion adsorbents." Diss., Connect to online resource - MSU authorized users, 2008.

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43

BENAISSA, MOHAMMED. "Etude par spectroscopie infrarouge des proprietes superficielles de l'alumine et des alumines sodees ou fluorees : acidite et basicite." Caen, 1985. http://www.theses.fr/1985CAEN2013.

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Etude des groupes superficiels de l'alumine et des cites d'adsorption. Etude de l'adsorption des alcools sur l'alumine degussa c, des sites d'adsorption et de l'acidite induite. Donnees, enfin, sur les alumines modifiees par des ions na+ ou f-

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44

Twumasi, Afriyie Ebenezer. "Preparation and Evaluation of New Nanoporous Silica Materials for Molecular Filtration and for Core Materials in Vacuum Insulation Panels." Doctoral thesis, KTH, Byggnadsteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-120330.

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Nanoporous materials for gas purification and thermal insulation have been studied and developed for application in many areas. It is known that a single adsorbent may not adequately control multiple contaminants. Further the utilization of nanoporous material as thermal insulator in building applications is limited due to high cost. Moreover, in view of the global environmental movement for clean air and reduction of heating energy consumption in built environment, the development of new and better nanoporous materials will not only facilitate major advances in gas adsorption and thermal insulation technology, but also meet the new challenges that cannot be met with the nanoporous materials that are currently available. This thesis presents a synthesis of new nanoporous silica based materials, and the characterization and application of these materials for molecular filtration and thermal insulation. Commercial nanoporous materials have been used for benchmarking for the pore properties, the applicability, and the performance of these new materials. First a double metal-silica adsorbent has been synthesized. The preparation procedure is based on the use of sodium silicate coagulated with various ratios of magnesium and calcium salts which yields micro-meso porous structures in the resulting material. The results show that molar ratios of Mg/Ca influence the pore parameters as well as the structure and morphology. The bimodal pore size can be tailored by controlling the Mg/Ca ratio. In the second synthesis, pure mesoporous silica, SNP has been prepared using glycerol as pore forming agent and monovalent salts as coagulant. This leads to material with large surface area and uniformed pore size centred at 43 or 47 nm. The materials further exhibits a low bulk density in the range of 0.077 to 0.122 g/ml and possess a high porosity in the range of 95-97%. The influence of acid type (organic or inorganic) on the pore parameters and on the tapped density has also been investigated. A synthesis method has also been developed for the preparation of carbon-silica composites. The method involves a number of routes, which can be summarised as addition of activated carbon particles to (I) the paste, (II) the salt solution, or (III) with the sodium silicate solution. In route II and III the activated carbon is present before coagulation. The routes presented here leads to carbon-silica composites possessing high micro porosity, meso porosity as well as large surface areas. The results further shows that pore size distribution may be tailored based on the route of addition of the carbon particles. Following route I and III a wide pore size (1-30 nm) was obtained whereas by route II a narrow pore size (1-4 nm) was observed. MgCa-silica chemisorbents were also developed using either potassium hydroxide or potassium permanganate as impregnate chemicals. A direct or post-impregnation procedure was employed. The results revealed that the impregnate route and amount cause a reduction in both specific surface area and pore volume. Finally the thermal conductivity and dynamic adsorption of H2S, SO2 andtoluene were measured. Results show that at room temperature and atmospheric pressure, a thermal conductivity of 28.4 and 29.6 mW/m.K were obtained for the SNP mesoporous silicas. The dynamic adsorption behaviour of the chemisorbents and composites indicate their ability to absorbed H2S, SO2 andtoluene respectively. The highest H2S uptake corresponds to chemisorbents with 11.2-13.6 wt% KMnO4. The effect of impregnation route, amount of KMnO4 and its location in the pore system are likely the key factors in achieving a large H2S uptake. For SO2 adsorption, the highest uptake capacity was observed for MgCa-68/32-KOH. The results further suggest that the key to large SO2 uptake is as a result of the synergetic effect between large mesopore diameter and extensive mesopore volumes. Carbon-silica composites with carbon content 45 wt % exhibits high toluene adsorption with composite via route I having the highest toluene adsorption capacity (27.6 wt % relative to carbon content). The large uptake capacity of this composite was attributed to the presence of high microporosity volume and a wide (1-30 nm) bimodal pore system consisting of extensive mesopore channels (2-30 nm) as well as large surface area. These capacity values of carbon-silica composites are competitive to results obtained for commercial coconut based carbon (31 wt %), and better than commercial alumina-carbon composite (9.5 wt %).

QC 20130408

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45

Gay, Simon Christopher Anthony. "Theoretical studies of adsorbate covered semiconductor surfaces." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302534.

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Gao, Weihong. "Adsorption of supercritical carbon dioxide on microporous adsorbents experiment and simulation /." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1114617964.

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Thesis (Ph. D.)--Ohio State University, 2005.
Title from first page of PDF file. Document formatted into pages; contains xii, 115 p.; also includes graphics. Includes bibliographical references (p. 107-115). Available online via OhioLINK's ETD Center

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Walton, Scott Gregory. "The role of adsorbed oxygen in secondary emission from metallic substrates." W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539623943.

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Low energy, ion- and photon-induced secondary electron and anion emission from metallic substrates has been investigated as a function of adsorbate coverage. Sodium positive ions (Na+), with kinetic energies up to 500 eV, and photons, with energies up to 23 eV, are utilized to initiate secondary emission. The principal adsorbate is oxygen with coverages ranging from none to a few monolayers.;For ion-induced emission, the secondary electron and negative ion absolute and relative yields from 302 stainless steel and polycrystalline tungsten (W) have been measured as a function of both impact energy and oxygen coverage. Additionally, the yields from a "technical" stainless steel surface, i.e., a surface for which no in-situ cleaning is performed, have been measured. The sputtered anions have been identified by secondary ion mass spectroscopy (SIMS). For both surfaces, adsorbate coverage is found to greatly enhance the electron and anion yields at all impact energies.;In addition, the kinetic energies of the secondary electrons and negative ions have been measured as a function of both impact energy and oxygen coverage. The electron and anion kinetic energy distributions exhibit low most probable energies (1--2 eV) and unique features that are substrate dependent.;Photoelectron kinetic energy distributions for aluminum (Al), molybdenum (Mo), Mo (100) and stainless steel have been measured, as a function of oxygen coverage, in order to ascertain the effects of adsorbed oxygen. Additionally, photon-stimulated anion desorption from oxygen covered Al has been measured as a function of photon energy. This anion desorption is found to have a narrow resonance at approximately 8.75 eV.;The resonance in the photon-induced anion emission is shown to be in direct support of a model proposed to explain the observed ion-induced secondary electron and O- emission from an oxygen covered Al surface. The model invokes a collision-induced excitation, of a surface state, that serves as a precursor to both electron and anion emission. This model is discussed in detail and utilized to explain the emission from oxygen covered stainless steel and tungsten. The results for the technical stainless steel surface are related to those for the oxygen covered surface and the implications for plasma discharge modeling are discussed.

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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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Wei, Jiayuan. "Preparation and characterization of nanocellulose-based carbon dioxide adsorbing aerogels." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-66166.

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CO2 adsorption is considered as a promising strategy to decrease the amount of CO2 in the atmosphere and stop global warming. The goal of this project is to prepare a cellulose-based CO2 adsorbent with a good mass transfer. Monolithic adsorbent based on cellulose nanofibrils (CNF) was fabricated via freeze-casting. 0.1g or 0.5g cellulose acetate (CA) or 0.1g acetylated CNC (aCNC) was dipped into the crosslinked aerogel to increase its CO2 capacity. Acetylation of CNC was confirmed by Fourier transformed infrared spectroscopy (FT-IR) and the degree of substitution was determined to be 1.6 through titration. Scanning electron microscopy (SEM) images showed that monolithic structure was formed through freeze-casting and the structure was maintained after dipping. Compression test suggested that the mechanical properties of the aerogel increased with the increasing amount of dipped CA, while the CO2 capacity of the adsorbent decreased. Furthermore, the outstanding reinforcing effect of aCNC was noticed in the compression test, and the aerogel dipped with aCNC has the highest CO2 capacity with a value of 1.49 mmol/g.

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Ortiz, Nilce. "Estudo da Utilização de Magnetita como Material Adsorvedor dos Metais Cu2+ , Pb2+ , Ni2+ e Cd2+ , em Solução." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-15022002-115714/.

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Alguns estudos do emprego de compostos de ferro como material adsorvedor não- convencional são citados em literatura. Foram feitos alguns testes da utilização de hematita (Fe2O3), o lodo galvânico e a lama de alto forno como adsorvedores para a remoção de metais pesados de efluentes industriais. A utilização de resíduo siderúrgico abundante, composto predominantemente por magnetita (Fe3O4), como adsorvedor não - convencional em processos de remoção de metais representa uma alternativa, de baixo custo, para o tratamento e adequação do efluente aos padrões de descarte de efluentes industriais exigidos pela legislação. Neste trabalho estudou-se a utilização de resíduo siderúrgico composto basicamente por magnetita como material adsorvedor para remoção de metais pesados em solução. O trabalho se concentrou no estudo da adsorção de quatro metais: cobre (Cu2+) , níquel (Ni2+) , chumbo (Pb2+) e o cádmio (Cd2+). Estes metais foram escolhidos devido a sua alta toxicidade e por estarem freqüentemente relacionados com efluentes de atividades industriais poluidoras. Os resultados obtidos permitiram concluir que, nas melhores condições de adsorção, o resíduo apresenta características adsorvedoras favoráveis a sua utilização industrial, com 97,84 % de remoção dos íons de cobre, 96,20 % de íons de chumbo, 61,70 % de íons de níquel e 87,22 % de íons de cádmio em solução. A velocidade de adsorção é proporcional a aquelas obtidas para outros adsorvedores não convencionais, e para a remoção dos íons de chumbo varia entre (92 e 115) 10-3mg g1 min-1 , e o sistema de adsorção possui características espontâneas e endotérmicas em adsorção ativada com característica parcial de adsorção química e está de acordo com os modelos propostos por Langmuir e por Freundlich, característico de processo de adsorção em monocamada, com sítios de adsorção de mesma energia e calor de adsorção equivalente.
Various references on the use of ferrous compounds as non - conventional adsorption materials can be found in literature. According to the literature, such materials as hematite, galvanic slag and blast furnace slag were successfully used in liquid waste treatment for heavy metals removal. Thus, the use of abundant ferrous metallurgy slag may prove to be efficient for low cost treatment of liquid industrial waste. The main goal of the present work is the study of converter slag application as adsorber material for heavy metals removal from liquid waste. The present research was aimed at soluble copper ( Cu2+), nickel ( Ni2+ ) , cadmium ( Cd2+ ) , and lead (Pb2+) removal. These metals were chosen because of their high toxicity, and because they are considered as the most common pollutants present in liquid industrial waste. The obtained results on converter slag adsorption properties under optimized adsorption conditions show that 97,84 % of copper, 61,70 % of nickel, 87,22 % of cadmium and 96,20 % of lead can be removed from the liquid waste. The achieved adsorption rates are comparable to those of conventional adsorbers, and for soluble lead removal rates in the range of ( 92 - 115). 10 -3 mg g -1 min -1 were established. Additionally, if was shown that the investigated adsorption system presented spontaneous and endothermic behavior under conditions of activated adsorption with partial chemical adsorption characteristics. Such pattern is in good agreement with the models proposed by Langmuir and Freundlich for monolayer adsorption processes with adsorption centers having equal energy and specific heat of adsorption. Overall, the obtained results indicate the viability of the investigated material for commercial application.

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Dissertations / Theses on the topic 'Adsorbent material'

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