Dissertations / Theses: 'Additive adsorption'

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Fritz, Susanne. "MD-Simulationen zur Adsorption von Additiven aus wässriger Lösung auf Calciumsulfat-Flächen." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2015. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-173886.

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Die Adsorption von Additiven an den Oberflächen eines Kristallisates wird als eine hauptsächliche Ursache für die Beeinflussung von Kristallwachstum und Morphologie angesehen und spielt bei vielen Kristallisationsprozessen eine entscheidende Rolle. Gerade für die Calciumsulfate, die im Millionen-Tonnen-Maßstab jährlich in Deutschland verarbeitet werden, stellt der Additiv-Einsatz einen Hauptkostenfaktor dar, während gleichzeitig die Additivwirkung mechanistisch nicht ausreichend gut verstanden und damit derzeit nicht vorhersagbar ist. Zur Erlangung eines besseren Verständnisses wurden mit Hilfe von molekulardynamischen Computersimulationen die Prozesse in den Grenzflächen zwischen festen Calciumsulfaten und wässriger Additivlösung auf atomarer Ebene analysiert. Wesentlicher Untersuchungsschwerpunkt war dabei die Rolle des polaren Lösungsmittels Wasser auf die Wechselwirkung zwischen verschiedenen ionischen Additivspezies und den Salzkristallen.

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Badens, Elisabeth. "Etude de l'adsorption de l'eau sur les cristaux de gypse et de son influence sur les propriétés mécaniques du plâtre pris pur et additive." Aix-Marseille 3, 1998. http://www.theses.fr/1998AIX30002.

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Le platre pris est un materiau constitue de cristaux de gypse enchevetres qui doit sa bonne cohesion a cet enchevetrement et aux interactions inter cristallines. Aux fortes humidites relatives, une perte de rigidite du materiau est observee. Des methodes de tests mecaniques non destructifs ont ete mises au point afin de suivre le comportement mecanique d'un meme echantillon de platre pris en fonction de sa teneur en eau. Les resultats des tests mecaniques traduisant un effet de l'eau a une echelle macroscopique ont ete correles a des mesures d'isotherme d'adsorption de l'eau sur le platre pris montrant le comportement de l'eau a une echelle microscopique. L'eau s'adsorberait preferentiellement au niveau des joints de grains et a partir d'une certaine epaisseur de la couche d'eau adsorbee, aux fortes humidites relatives, l'eau acquiert les proprietes de l'eau libre et entraine la perte de rigidite du materiau. Un mouillage partiel de l'eau sur la face (010) d'un monocristal de gypse a ete observe. Une etude de la tenue en fluage du platre pris a mis en evidence un glissement visqueux des cristaux de gypse les uns sur les autres a une humidite relative de 97% et a temperature ambiante. Des travaux ont ete consacres a l'etude d'additifs susceptibles d'ameliorer la rigidite du platre pris en milieu humide. Nous avons etudie l'influence des additifs sur le retard a la cristallisation du gypse, sur la morphologie et le facies du cristal de gypse et enfin sur les proprietes mecaniques du platre pris sec ou humide. L'adsorption des additifs sur les cristaux de gypse et leur incorporation ont ete caracterisees par electrophorese capillaire et une bonne correlation a ete mise en evidence entre la quantite d'additif adsorbee et le retard a la cristallisation du gypse.

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Banik, Stephen John II. "Suppressing Dendritic Growth during Zinc Electrodeposition using Polyethylenimine as an Electrolyte Additive for Rechargeable Zinc Batteries." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459266964.

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Trindade, Eduardo Dominguez. "Efeito do tipo de óleo básico no desempenho tribológico de dialquilditiocarbamato de molibdênio como aditivo para lubrificantes automotivos." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-23122014-152226/.

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A otimização da formulação do óleo lubrificante empregado em motores de combustão interna é uma importante maneira de se reduzir o atrito e assim aumentar a eficiência energética. É também uma forma de assegurar proteção ao sistema, mantendo a taxa de desgaste em um nível adequado. O óleo de motor é uma mistura de óleos básicos selecionados com aditivos, entre os quais podem ser encontrados os modificadores de atrito, que são compostos com capacidade de aderir às superfícies metálicas, proporcionando melhoria da lubrificação em condições mista e limítrofe. O dialquilditiocarbamato de molibdênio (MoDTC) está entre os mais importantes redutores de atrito empregados em óleos lubrificantes. Ésteres sintéticos podem ser usados como óleos básicos em algumas formulações. Visto que ésteres são mais polares que hidrocarbonetos, essas moléculas podem atuar modificando propriedades do óleo na região próxima à superfície metálica. Podem também interferir com filmes adsorvidos, limitando sua efetividade. O objetivo do trabalho é a comparação dos efeitos do MoDTC em diferentes misturas contendo hidrocarboneto e éster. Para isso, formulações lubrificantes contendo uma polialfaolefina, um diéster e um aditivo à base de MoDTC foram preparadas, caracterizadas e ensaiadas em tribômetro oscilatório SRV usando configuração esfera-disco. Foram empregadas esferas de aço AISI 52100 e discos de aço AISI H13. Foi estudada a influência da variação da temperatura e da força normal aplicada. Empregando-se mistura de hidrocarboneto e éster como lubrificante, o aumento da temperatura causou leve aumento do coeficiente de atrito. Em ausência de MoDTC, a presença de éster aumentou a capacidade de suportação de carga das formulações. Os testes com óleos contendo MoDTC foram marcados pela ocorrência de dois fenômenos: ativação e depleção do aditivo. Estes fenômenos se mostraram dependentes da carga normal e da composição do óleo. O efeito de redução do atrito pelo MoDTC tende a ser menos duradouro com óleos mais ricos em éster e em condições de carregamento mais severo. O comportamento tribológico do éster em mistura com polialfaolefina, medido através do coeficiente de atrito, seguiu a isoterma de adsorção de Frumkin, com alguma atração entre as moléculas do éster, e energia livre da ordem de -4 kJ/mol, típica de fisissorção. Óleos envelhecidos artificialmente foram testados e não apresentaram diferenças significativas com relação aos mesmos óleos novos. A adição de etanol aos óleos envelhecidos causou uma leve diminuição no coeficiente de atrito a 40 °C; tal efeito não foi perceptível em temperaturas mais altas, provavelmente devido à perda por evaporação do álcool.
The optimization of the lubricant oil formulation used in internal combustion engines is an important way of reducing friction, thus increasing energetic efficiency. It is also a way of protecting the system, maintaining wear rate in an adequate level. The engine oil is a blend of selected base oils with additives, amongst which are the friction modifiers substances able to adhere to the metal surfaces, thus providing better lubrication at the mixed and boundary regimes. Molybdenum dialkyldithiocarbamate (MoDTC) is amongst the most important friction reducers used in lubricant oils. Synthetic esters may be employed as base oils in some formulations as well. Given that esters are more polar than hydrocarbons, these molecules can actuate by modifying oil properties in the near-surface region. They can also interfere with adsorbed films, preventing their effectiveness. The objective of this work is the comparison of the effects of MoDTC in different mixtures containing hydrocarbon and ester. With this aim, lubricating formulations containing a polyalphaolefin, a diester and a MoDTC-based additive were prepared, characterized and tested in a reciprocating SRV tribometer using ball-on-disc configuration. AISI 52100 steel balls and AISI H13 steel discs were employed. The influences of the temperature and of the normal load were both studied. Employing a mixture of hydrocarbon and ester as lubricant, a higher temperature caused a slightly higher coefficient of friction in the lubricant free of additive. In the absence of MoDTC, the ester increased the load-carrying capacity of the lubricant formulations. Tests with MoDTC-containing oils were characterized by two phenomena: activation and depletion of the additive. These phenomena showed to be dependent on the normal load and on the oil composition. The MoDTC friction reducing effect tends to be less sustainable with higher ester concentrations and at higher loads. The tribological behavior of the ester in the presence of polyalphaolefin, as measured by the coefficient of friction, followed the Frumkin adsorption isotherm, with some attraction between ester molecules, and free energy in the order of -4 kJ/mol, typical of physisorption. Artificially aged oils were tested and did not show differences when compared with the results of the fresh oils. Adding ethanol to the aged oils caused a slightly reduction in the coefficient of friction at 40 °C, but this effect was not observed at higher temperatures, probably due to evaporation loss of the alcohol.

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Schneider, Jana. "Beitrag zur Wirkungsweise von Verzögerern beim Abbinden von Stuckgipsen." Doctoral thesis, TU Bergakademie Freiberg, 2009. https://tubaf.qucosa.de/id/qucosa%3A22717.

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In dieser Arbeit wurde der Einfluss verschiedener Additive (Carbonsäuren, Phosphonsäuren und Retardan P) auf die einzelnen Teilprozesse des Abbindens von Gips an technischen und synthetischen Halbhydraten unter vergleichbaren Bedingungen untersucht. Vorrangig bei der Keimbildung und beim Kristallwachstum wurde ein Einfluss der Additive beobachtet. Das pH-abhängige Wirkungsoptimum kann mit der Speziation der Additive erklärt werden. Ihre Wirkung wird durch Adsorption auf CaSO4-Oberflächen verursacht. Die Untersuchungen ergaben eine bevorzugte Ca-Affinität mit den Flächen (120) und (001) zunehmend von Citronensäure über Weinsäure, HEDP zu HDTMP. Die in verdünnten homogenen Lösungen erhaltenen Ergebnisse sind nicht direkt auf den Abbindeprozess in Pasten übertragbar. In-situ Ramanspektroskopie und Auswaschexperimente weisen in Pasten auf irreversible Adsorption und ein Überwachsen der Additive hin, was zur Abnahme ihrer Wirkung führt. Auf die Festigkeit der abgebundenen Gipskörper zeigen die Additive kaum Einfluss.

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Schneider, Jana. "Beitrag zur Wirkungsweise von Verzögerern beim Abbinden von Stuckgipsen." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola&quot, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-27696.

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In dieser Arbeit wurde der Einfluss verschiedener Additive (Carbonsäuren, Phosphonsäuren und Retardan P) auf die einzelnen Teilprozesse des Abbindens von Gips an technischen und synthetischen Halbhydraten unter vergleichbaren Bedingungen untersucht. Vorrangig bei der Keimbildung und beim Kristallwachstum wurde ein Einfluss der Additive beobachtet. Das pH-abhängige Wirkungsoptimum kann mit der Speziation der Additive erklärt werden. Ihre Wirkung wird durch Adsorption auf CaSO4-Oberflächen verursacht. Die Untersuchungen ergaben eine bevorzugte Ca-Affinität mit den Flächen (120) und (001) zunehmend von Citronensäure über Weinsäure, HEDP zu HDTMP. Die in verdünnten homogenen Lösungen erhaltenen Ergebnisse sind nicht direkt auf den Abbindeprozess in Pasten übertragbar. In-situ Ramanspektroskopie und Auswaschexperimente weisen in Pasten auf irreversible Adsorption und ein Überwachsen der Additive hin, was zur Abnahme ihrer Wirkung führt. Auf die Festigkeit der abgebundenen Gipskörper zeigen die Additive kaum Einfluss.

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Momeni, Matin. "Adsorption of fuel additives on metal surfaces." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=201933.

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Efstathiou, Eirini. "Adsorption of novel lubricant additives from dodecane onto solid surfaces." Thesis, University of Hull, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430985.

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Liu, Jin. "Effects of Chemical Additives on the Light Weight Paper." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/7626.

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Tissue, among the highest value added paper products, finds extensive application in modern society. Continued efforts are being made to further improve tissue properties, such as strength, softness and water absorbency. Besides the efforts on characterizing facial tissue softness, this study focuses on tissue quality improvement through chemical means. The application of a wet strength resin, Kymene1500 and a debonding agent, Softrite7516 onto cellulose fibers is considered. First, the adsorption kinetics of the two chemical additives onto cellulose fibers was studied. The adsorption mechanisms were proposed and validated by kinetic data. A novel apparatus was designed in this study, and represented the first in the field to collect real-time data, which has the potential to be applied to the adsorption kinetic study of other types of paper additives. Second, the effects of Kymene1500 and Softrite7516 on various sheet properties were studied. The results provide quantitative information on tissue additives effects on sheet properties. It is shown that the combined application of the additives can overcome the disadvantages of individual species and produce sheets with both wet strength and softness. Finally, environmental-benign debonding agents with polyoxyethylene chains were applied to the sheets, and the effects of two design parameters, i.e., fatty acid and degree of ethoxylation, on tissue properties were investigated.

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Kozak, Darby Merrick. "The adsorption and stabilising effect of fuel additives on carbon black and steel surfaces." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420903.

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Ward, Philip R. "Generation of water repellence in sands, and its amelioration by clay addition /." Adelaide, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phw262.pdf.

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Ajouyed, Omar. "Adsorption du Cr(VI) par différents minéraux naturels : application au traitement des sédiments portuaires." Nice, 2011. http://www.theses.fr/2011NICE4082.

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Le devenir des sédiments de dragage est une problématique majeure dans certains pays, essentiellement au Royaume du Maroc, en raison d’une contamination significative en polluants organiques et minéraux. La mise en dépôt de sédiments de dragage contaminés doit donc s’accompagner d’un traitement permettant de limiter la dispersion des polluants dans l’environnement. Cette étude a été réalisée afin de réduire la mobilité des métaux lourds au cours de stockage des boues de dragage contaminés. Le premier objectif de la thèse est de déterminer les mécanismes de fixation du Cr(VI) et de sélectionner le matériau adsorbant le plus efficace. Le deuxième objectif est de caractériser chimiquement des sédiments portuaires et d’étudier la faisabilité d’utiliser un additif minéral comme agent de stabilisation des métaux dans les sédiments. Des minéraux argileux (kaolinite et illite) et des oxy-hydroxydes (hématite, goethite et -alumine) sont envisagées pour cette étude étant donnée leur présence naturelle dans les sédiments et leur forte capacité de rétention vis-à-vis du Cr(VI). L’étude de l’adsorption du Cr(VI) par ces adsorbants, montre que la capacité d’adsorption de cet élément est importante dans le cas de l’hématite et de la kaolinite. Les modèles de Langmuir et de Freundlich sont respectivement introduits pour expliquer la relation entre les ions fixés par les milieux réactionnels et la concentration d’ion à l’équilibre dans les solutions. Le modèle de Langmuir est plus représentatif pour les oxy-hydroxydes métalliques et le modèle de Freundlich est plus représentatif pour les minéraux argileux et le mélange. Des expériences de lixiviation en batch ont été utilisés pour évaluer l’efficacité de l’hématite et de la kaolinite comme additifs. Les résultats montrent que l’ajout d’un stabilisant pourrait être une technique efficace et fiable pour l’immobilisation de chrome et d’autres métaux lourds dans les sédiments de dragage contaminés
The fate of dredged sediments is a major problem in some countries, mainly in Morocco, due to significant contamination organic and mineral pollutants. Land disposal dredged sediment must be accompanied treatment to limit the dispersion of pollutants in the environment. This study is carried out to reduce the mobility of heavy metals during storage of dredging contaminated. The first objective is to determine the adsorption mechanisms of Cr (VI) and selects the adsorbent the most efficient. The second objective is the chemical characterization of harbour sediments and to study the feasibility of using a mineral additive as a stabilizer of metals in sediments. Clay minerals (kaolinite and illite) and metal oxy-hydroxides (hematite, goethite and -alumina) are being considered for this study given their natural occurrence in sediments and their high retention capacity. The study of the adsorption of Cr(VI) by these adsorbents shows that the adsorption capacity of this element is important in the case of hematite and kaolinite. Langmuir and Freundlich adsorption isotherms are employed to understand the nature of adsorption at room temperature. The characteristic parameters for each isotherm have been determined. This showed that the Langmuir and Freundlich models are representative for the metal oxy-hydroxides and the clay minerals, repectively. Batch leaching methods were used to evaluate the effectiveness of hematite and kaolinite, as additives for reducing the mobilization of heavy metals, especially chromium, from contaminated sediments. The results show that the addition of amendments could be a successful and reliable technique for stabilization of chromium and other metals in contaminated sediment

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Luettgen, Christopher O. "An Investigation of the role of mixing conditions during polymeric retention aid addition on the adsorption homogeneity." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/5787.

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Spinozzi, Di Sante Lisa. "Heterogenization of an organic catalyst by adsorption on alginic acid gels." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14425/.

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A sustainable approach focused on the practice of green chemistry was used to develop a method which improved the performances of a catalyst system based on a natural and non-toxic substance. A benchmark Michael addition reaction was performed employing 9-amino(9-deoxy)epi quinine, adsorbed on alginic acid gels by hydrogen bonds, as catalyst. Compared to conventional heterogeneization of this organic catalyst, the present approach is more straightforward and employs as support a renewable biomaterial instead of oil-derived polymers. The optimization of the adsorption protocol was carried out to obtain an active and heterogeneous system able to work under different reaction temperatures. The Michael addition reaction rate, heterogeneity, enantiomeric excess and recyclability of the catalytic system were studied. The influence of temperature, additives and the presence of water were successfully investigated. The heterogeneity of the catalyst was perfectly preserved, therefore the catalyst could be easily recovered. Two optimal conditions were disclosed, differing in reaction temperature and catalyst pre-treatment. A scale-up is performed with good results for the first three reactions cycles (conversions: 100%, 87% and 55% respectively). The enantiomeric excess is determined as 98%. The results of this project demonstrated that a green catalytic system has a great potential to be competitive with more classic heterogeneous catalysts.

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Androniuk, Iuliia. "Effects of cement organic additives on the adsorption of uranyl ions on calcium silicate hydrate phases : experimental determination and computational molecular modelling." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2017. http://www.theses.fr/2017IMTA0007/document.

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Les matériaux cimentaires sont largement utilisés dans la conception et la construction des sites de stockage de déchets radioactifs. Une des manières d’améliorer leur performance est d’introduire des adjuvants organiques dans la structure. La présence de matière organique dans l’eau porale peut affecter la mobilité des radionucléides : les molécules organiques forment des complexes solubles et peuvent être en compétition avec les radionucléides au niveau des sites de sorption. Ce travail avait pour but de comprendre les mécanismes de telles interactions au niveau moléculaire. Le système modèle a trois composantes. D’abord, des phases C-S-H ont été choisies en tant que modèles du ciment.Ensuite, le gluconate est sélectionné en tant que modèle d’additif organique pour sonder les mécanismes d’interaction à l’échelle moléculaire. Un système plus complexe impliquant un superplastifiant (PCE) a été testé. La troisième espèce, U(VI), est représentative d’un radionucléide de la série des actinides. Le développement de la description des effets de postproduction des espèces organiques pour les applications de stockage des déchets radioactifs était l’objectif principal de ce travail. L’étude des systèmes binaires fournit des données de référence pour l’investigation de systèmes ternaires C-S-H/matière organique/U(VI) plus complexes. Des cinétiques et des isothermes de sorption/désorption pour les espèces sur les C-S-H sont mesurés. En parallèle, des modèles atomiques ont été développés pour les interfaces d’intérêt. Les aspects structuraux, énergétiques et dynamiques des processus de sorption sur les surfaces de ciment sont modélisés par la technique de la dynamique moléculaire
Cementitious materials are extensively used in the design and construction of radioactive waste repositories. One of the ways to enhance their performance is to introduce organic admixtures into the cement structure. However, the presence of organics in the pore water may affect the radionuclide mobility: organic molecules can form water-soluble complexes and compete for sorption sites. This work was designed to get detailed understanding of the mechanisms of such interactions on the molecular level. The model system has three components. First, pure C-S-H phases with different Ca/Si ratios were chosen as a cement model. Secondly, gluconate (a simple well-described molecule) is selected as a good starting organic additive model to probe the interaction mechanisms on the molecular scale. A more complex system involving polycarboxylate superplasticizer (PCE) was also tested. The third, U (VI), is a representative of the actinide radionuclide series. The development of description of the effects of organics for radioactive waste disposal applications was the primary objective of this work. The study of binary systems provides reference data for the investigation of more complex ternary (C-S-H/organic/U(VI)). The interactions are studied by means of both experimental and computational molecular modelling techniques. Data on sorption and desorption kinetics and isotherms for additives and for U (VI) on C-S-H are acquired in this work. In parallel, atomistic models are developed for the interfaces of interest. Structural, energetic, and dynamic aspects of the sorption processes on surface of cement are quantitatively modeled by molecular dynamics technique

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Dombek, Priscilla Emily 1961. "IMPROVING THE CONVERSION OF THE SULFUR DIOXIDE - LIME REACTION BY USING ADDITIVES." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/291523.

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Abidi, Nejib. "Interactions argiles naturelles-effluents teinturiers : influence des propriétés de surface des argiles et mécanismes d'adsorption des colorants." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAH005/document.

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Les effluents industriels issus des activités de textile présentent souvent une importante charge polluante colorante difficilement biodégradable. Des travaux antérieurs ont montré le potentiel des argiles naturelles non traitées à dépolluer ces effluents teinturiers alors qu’ils sont généralement composés de colorants anioniques difficilement adsorbables sur ces supports. Or, les effluents contiennent également d’autres composés chimiques utilisés dans les différentes étapes du procédé de teinture, et qui sont de natures variées (sels, acides, bases, détergents, dérivés enzymatiques, etc…). Il semblerait que ces produits auxiliaires jouent un rôle dans l'adsorption de colorants anioniques sur l'argile non traitée. Cependant, aucune étude connue à ce jour, n'a porté sur l'effet des additifs de teinture dans le processus de décoloration par des absorbants en général, et par les argiles en particulier. Cette étude est la première à s’intéresser au système colorant-additif-argile. Des tests d’adsorption / désorption en batch ont été menés en considérant différents systèmes colorant-additif-argile. Les résultats des tests montrent que les additifs de type enzymatique favorisent l’adsorption de colorant anionique sur l’argile en neutralisant les charges négatives et en renforçant les liaisons argile-colorant. D’autres additifs ont un effet contraire mais n’annulent pas l’effet positif des additifs enzymatiques lorsqu’ils sont mélangés dans l’effluent. Des hypothèses d’interactions mises en jeu lors de l’adsorption de colorant ont été faites en s’aidant des résultats de la spectrométrie infra-rouge et de masse, de la zétamétrie et de la modélisation des isothermes d’adsorption
Industrial effluents from textile activities often have a high pollution load readily biodegradable. Previous work has shown the potential of natural untreated clays to clean up these dyers effluents although anionic dyes are not easily absorbable on these media. The effluents also contain other chemical compounds used in the different stages of the dyeing process, and which are of various natures (salts, acids, bases, detergents, enzyme derivatives, etc ...). It appears that these auxiliary products play a role in the adsorption of anionic dyes on untreated clay. However, no currently known study has examined the effect of the additives from the dyeing process on the adsorption of dye onto clay. This is the first study to focus on the dye-clay-additive system. Adsorption / desorption batch tests were conducted considering different dye additive-clay systems. The tests’ results show that the enzyme like additives enhance the adsorption of anionic dye on the clay by neutralizing the negative charges and reinforcing clay-dye links. Other additives have the opposite effect, but do not offset the positive effect of enzyme like additives when mixed in the effluent. Assumptions of interactions involved in dye adsorption were made with the help of the results of infrared and mass spectrometry, zetametry and the modeling of adsorption isotherms

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Chhim, Norinda. "Effets d'additifs polymériques sur les cinétiques de précipitation de carbonate de calcium en présence de matières en suspension et de matériaux de corps d'échange thermique : applications aux circuits de refroidissement industriels." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0024.

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Ces travaux de thèse portent sur l’effet d’additifs polymériques sur les cinétiques de précipitation de carbonate de calcium en présence de matières en suspension (MES) et de surfaces de matériaux représentatifs des corps d’échange thermique mis en oeuvre dans les circuits de refroidissement industriels (CRF). Pour mener cette étude à l’échelle du laboratoire un dispositif à composition constante est mis au point pour reproduire les conditions d’exploitation d’un CRF. En absence d’inhibiteur, la vitesse de croissance des cristaux de CaCO3 augmente avec l’augmentation de la concentration en MES dans l’eau circulant dans le CRF. Dans la gamme de températures opérationnelles du CRF, la vitesse de croissance cristalline augmente avec l’augmentation de la température. La performance d’inhibition de la croissance des cristaux deCaCO3 de cinq additifs, en présence de semences de calcite est évaluée. L’homopolymère acrylique (HA) appartenant à la famille des additifs « conventionnels » et l’acide polyaspartique (PASP) de la famille des additifs « verts » présentent les meilleures performances. Le taux d’inhibition décroît avec l’augmentation de la température. Sur les cinq additifs, quatre sont des inhibiteurs de la croissance (acide citrique, HA, copolymère carboxylique, PASP) et un est un inhibiteur de la nucléation (acide polyépoxysuccinique PESA). L’utilisation d’un mélange d’inhibiteur de nucléation (PESA) et d’un inhibiteur de croissance, en particulier le PASP, a permis de rallonger le temps de latence apparent de la croissance de CaCO3 (supérieur à 18 heures) temps que l’on peut comparer au temps de séjour de l’eau dans un CRF, tout en assurant un taux d’inhibition de la croissance de 85 à 89 %. Le temps de latence apparent augmente avec l’augmentation de la concentration en PESA dans le mélange. L’inhibition de la croissance résulte de l’adsorption des molécules d’additif polymérique sur les sites de de croissance des cristaux suivant le modèle d’adsorption de Langmuir. Les matériaux PVC constitutifs de corps d’échange thermique mis en contact avec la solution sursaturée en présence de semences de calcite conduisent également à des vitesses de croissance cristalline supérieures à celle observée sur les semences de calcite. La présence d’additif polymérique HA a permis d’inhiber la croissance cristalline sur la surface du PVC d’environ 90 %. L’inhibition de la croissance cristalline sur la surface du PVC résulte également de l’adsorption des molécules d’additif sur les sites actifs. A l’échelle industrielle, des essais ont été menés sur des installations pilotes dans des conditions similaires à celles utilisées en laboratoire. Les résultats ont été simulés à l’aide du logiciel CooliSS (Cooling circuit Simulation Software) développé par EDF R&D en utilisant une loi locale d’inhibition, proposée à partir des données locales acquises en laboratoire et des mesures de dépôt sur des coupons de matériaux introduits dans les pilotes à différents endroits du circuit. Les facteurs d’efficacité de l’additif polymérique dépendent de la nature de matériau (Inox et PVC) et de la présence de MES dans le CRF. Une meilleure corrélation entre les résultats expérimentaux obtenus sur les installations pilotes et ceux simulés par le logiciel CooliSS est obtenue pour des facteurs d’efficacité respectifs de 0,753 pour le matériau d’inox (condenseur) et 0,785 pour le matériau PVC (garnissage dans le réfrigérant atmosphérique). Cependant, les améliorations de la sensibilité de la simulation restent à apporter en agissant sur la relation entre ces facteurs d’efficacité et la concentration en MES
This thesis focuses on the effect of polymeric additives on calcium carbonate precipitation kinetics in the presence of suspended matters and material surfaces representative of heat exchange materials found in industrial cooling systems (ICS). A laboratory set-up based on constant composition method crystallisation was adapted to the operating conditions of ICS and used to determine growth kinetics of calcium carbonate crystals. In the absence of polymeric inhibitors, the growth rate of the CaCO3 crystals increases with increasing suspended maters concentration in the circulating water of ICS. In the operational temperature range of ICS, the crystal growth rate increases with increasing temperature. The CaCO3 crystals growth inhibition efficiency of five additives, in the presence of calcite seeds is evaluated. Acrylic homopolymer (AH) belonging to « conventional » additives family and polyaspartic acid (PASP) qualified of « green » polymeric additive, have revealed the best efficiency. The inhibition rate decreases with increasing temperature. Among these five additives tested, four are growth inhibitors (citric acid, AH, carboxylic copolymer, PASP) and one is a nucleation inhibitor (PESA polyepoxysuccinic acid). The synergistic effect of a mixture of nucleation inhibitor (PESA) and a growth inhibitor, in particular PASP, on inhibition of CaCO3 has been studied. Results showed that the anti-scaling performance of PASP combined with PESA is superior to PASP or PESA used alone, for CaCO3 and the apparent time latency of CaCO3 crystals growth increases (greater than 18 hours). This apparent time latency could be compared to the residence time of the water in ICS, while ensuring an inhibition rate of 85 to 89 %. The apparent time latency increases with increasing concentration of PESA in the mixture. Growth inhibition results from adsorption of polymeric additive molecules onto crystal growth sites according to the Langmuir adsorption model. The PVC materials used as heat exchanger in atmospheric refrigerant has been studied in the supersaturated solution in the presence of calcite seeds. Results showed that the crystals growth rates are higher than thoseobtained with calcite seeds alone in supersaturated solution. The inhibition rate of CaCO3 crystal growth on PVC material by polymeric additive AH is evaluated to about 90%. The CaCO3 crystal growth inhibition on PVC surface also results from adsorption of polymeric additive molecules on active sites. At the industrial scale, experiments were carried out on pilot plants, in conditions similar to those used at the laboratory scale. The results were simulated by using the CooliSS software (Cooling circuit Simulation Software) developed by EDF R & D. Results showed that it is possible to reproduce the trends observed in the pilot plants, by introducing in the model a local inhibition law, determined by combining the acquired local data obtained in the laboratory device and the data issued from different material samples (stainless steel, PVC) introduced in different locations of the industrial pilot plants. The sensitivity of these trends seems to be related to the efficiency factors. These efficiency factors depend on the nature of the material and the presence of MES in the cooling water. The best correlation between the pilot plants experimental results and those simulated by CooliSS software is obtained, for stainless steel efficiency factors equal to 0.753 (condenser tubes) and equal to 0.785 for PVC material (packing in refrigerant atmospheric). However, the improvements of the simulation sensitivity remain necessary by working on the relationship between these efficiency factors and suspended matters concentration

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19

Proxmire, Paul R. "The influence of aluminum salts on the retention of titanium dioxide when using cationic polyelectrolyte as a retention aid." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/5533.

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Fritz, Susanne [Verfasser], Wolfgang [Akademischer Betreuer] Voigt, Wolfgang [Gutachter] Voigt, and Joachim [Gutachter] Ulrich. "MD-Simulationen zur Adsorption von Additiven aus wässriger Lösung auf Calciumsulfat-Flächen / Susanne Fritz ; Gutachter: Wolfgang Voigt, Joachim Ulrich ; Betreuer: Wolfgang Voigt." Freiberg : Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2015. http://d-nb.info/1220837962/34.

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21

Meudre, Charline. "Obtention de revêtements électrochimiques de bronze en milieu acide avec ajout d'additifs organique à base de gélatine." Thesis, Besançon, 2015. http://www.theses.fr/2015BESA2011/document.

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Les normes environnementales, en constante évolution, deviennent de plus en plus strictes pour réduire la présence de métaux et / ou composés organiques volatils dans l’environnement. Cette restriction constitue donc une préoccupation industrielle majeure dans le domaine des traitements de surface où les métaux sont prépondérants. Depuis peu le nickel a été placé en CMR (cancérogène, mutagène et reprotoxique) et appartient donc à la liste de produits à éviter. En conséquence, des alternatives au revêtement de nickel sont très sollicitées par les industriels afin de respecter l’environnement tout en gardant les mêmes performances de dépôts que le nickel (bonne résistance à la corrosion,…). Notre axe de recherche concerne la formulation et la caractérisation de dépôts électrolytiques d’alliages cuivre – étain considérés comme alternative au nickel. Une première partie porte sur les mécanisme d’électrodéposition des alliage cuivre étain en présence de gélatine et en milieu acide et sulfate. Une deuxième partie apporte des compléments d’informations sur les mécanismes mis en œuvre lors de l’électrodéposition des alliages CuSn. La gélatine, présent [Sic] dans l’électrolyte, modifie les revêtements CuSn élaborés identifiant un phénomène d’adsorption de substrat de platine. Un mode d’action de la gélatine suivant le modèle de Norde a été proposé. Cette étude s’oriente vers une application industrielle, c’est pourquoi une troisième partie est dédiée à l’élaboration et la caractérisation des revêtements CuSn sur différents substrats (laiton, acier
To date, nickel electrodeposition plays a key role in a variety of decorative, engineering and electroforming applications due to its costs that are maintained at an acceptable level, and their excellent functional properties (corrosion resistance…). Environmental constraints lead to increasingly severe regulations. […] This study focuses on the formulation of an acid and sulfate electrolyte. […] In the present study, deposition of Cu-Sn on platinum substrate was studied, and the role of gelatin at the interface was investigated. A phenomenon of gelatin adsorption is determined by different techniques of the characterization. The third part of this study deals with the electrodeposition of CuSn alloys on different substrates moving towards industrial application. The end goal is to identify optimum operating conditions based on gelatin action

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Mohammed, Saad Abdul Basset. "Caracterisation par spectroscopie ft-ir de l'adsorption et de la reactivite de composes sulfures sur alumine : effet de l'ajout de sodium." Caen, 1986. http://www.theses.fr/1986CAEN2030.

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La spectroscopie ft-ir est appliquee a l'etude des proprietes superficielles d'echantillons d'alumine, a la determination de la nature des especes donnees par l'adsorption de composes soufres et a la recherche des intermediaires de reaction pouvant expliquer le mecanisme du procede de claus. L'addition de na**(+), diminue l'acidite de lewis de l'alumine. L'acidite de broensted induite par la presence des especes sulfate est certainement cause de la desactivation de l'alumine dans la reaction de conversion oxydante de h::(2)s. Cas, aussi, de l'adsorption sur de la silice sodee

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23

Yusran, Fadly Hairannoor. "Soil organic matter decomposition : effects of organic matter addition on phosphorus dynamics in lateritic soils." University of Western Australia. School of Earth and Geographical Sciences, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0120.

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[Truncated abstract] Relationships between the persistence of organic matter added to soil, the dynamics of soil organic carbon (C) and phosphorus (P) were examined in four experiments on lateritic soils of Western Australia. The main objective was to quantify the release of P following organic matter application in soils which have high P adsorbing capacity. Another objective was to confirm that due to its recalcitrant materials, the effect of peat lasted longer in soil than other sources of organic matter in terms of increasing plant-available P fractions. Three experiments were conducted under glasshouse conditions for various lengths of time, with nine- to twelve-month incubations to investigate these hypotheses. As expected, organic matter with lower C:N ratios than peat (lucerne hay) decomposed more rapidly compared with peat, and the most active mineralisation took place within the first three months of incubation. Soil organic-C (extracted by 0.5 M K2SO4) had a significant positive correlation with P extracted with 0.5 M NaHCO pH 8.53. For a higher application rate (120 ton ha-1), peat was better than wheat straw and lucerne hay in increasing extractable bicarbonate-P concentrations in soil, especially at incubation times up to 12 months. Throughout the experiment, peat was associated with a steady increase in all parameters measured. In contrast to peat, nutrient release from lucerne hay and wheat straw was rapid and diminished over time. There was a tendency for organic-C (either in the form of total extractable organic-C or microbial biomass-C) to steadily increase in soil with added peat throughout the experiment. Unlike wheat straw and lucerne hay, extractable organic-C from peat remained in soil and there was less C loss in the form of respiration. Therefore, peat persisted and sequestered C to the soil system for a longer time than the other source of organic matter. Freshly added organic matter was expected to have a greater influence on P transformation from adsorbed forms in lateritic soils than existing soil organic matter. By removing the existing soil organic matter, the effect of freshly applied organic matter can be determine separately from that of the existing soil organic matter for a similar organic-C content. In order to do this, some soil samples were combusted up to 450° C to eliminate inherent soil organic matter. The release of P was greater when organic-C from fresh organic matter was applied to combusted soils than in uncombusted soils that contained the existing soil organic matter. The exception only applied for parameters related to soil micro-organisms such as biomass-C and phosphatase. For such parameters, new soil organic matter did not create conditions favourable for organisms to increase in activity despite the abundance of organic matter available. More non-extractable-P was formed in combusted soils compared to bicarbonate-P and it contributed to more than 50% of total-P. As for the first experiment, peat also showed a constant effect in increasing bicarbonate extractable-P in the soil

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Vanlerberghe, Aldo. "Mise au point et applications de la spectrométrie IR-TF à l'analyse par réflexion externe et diffuse des films formés par adsorption et frottement des additifs de lubrifiant sur surfaces métalliques." Aix-Marseille 3, 1988. http://www.theses.fr/1988AIX30033.

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25

Nalet, Camille. "Influence de la stéréochimie et de la fonctionnalité de molécules organiques sur l'hydratation de composés cimentaires." Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS086/document.

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Le manque de connaissance sur les interactions existantes entre les adjuvants organiques et les phases minérales ainsi que leur influence sur les mécanismes d’hydratation du Ciment Portland Ordinaire (CPO) limite le développement de nouvelles molécules organiques avec des propriétés améliorées et contrôlées. Ici, le but de ces travaux était de comprendre pourquoi et comment des adjuvants organiques modifient le temps de prise du CPO en faisant varier progressivement les caractéristiques de molécules organiques simples comme leur charge, leurs groupes fonctionnels (hydroxyle, hydroxy-carboxylate, carboxylate, sulfonate et phosphonate) et la stéréochimie de leurs groupes hydroxyles.Les différents retards induits par les molécules organiques étudiées sur l’hydratation du composé minéral responsable des propriétés finales du CPO, le silicate tricalcique, ont été reliés aux caractéristiques des composés organiques. Les interactions de ces derniers dont leur adsorption sur du silicate de calcium hydraté (C-S-H) ainsi que leur complexation avec les ions calcium, hydroxyde et/ou silicates en solution ont été identifiées dans des systèmes à l’équilibre et corrélées au retard généré par les molécules organiques sur l’hydratation du silicate tricalcique.L’impact des hexitols qui varient uniquement en fonction de la stéréochimie de leurs groupes hydroxyles sur le processus de dissolution-précipitation de l’hydratation du silicate tricalcique a été étudié. L’influence de ces polyols sur l’hydratation d’un mélange luminatesulfate de calcium a été expliquée par leur adsorption sur l’ettringite, les AFm et par leur complexation ionique en solution. Pour finir, cette étude s’est focalisée sur les conséquences des interactions des hexitols avec l’ettringite et les ions aluminate en solution sur l’hydratation des phases silicates présentes dans le CPO
The current limited knowledge on the interactions between organic admixtures and mineral phases as well as their influence on the hydration mechanisms of the Ordinary Portland Cement (OPC) represents a real limitation in the development of new organic products with improved and controlled properties. Here, this study intended to understand why and how organic admixtures modify the setting time of OPC by progressively varying the characteristics of simple organic molecules such as their charge, functional groups (hydroxyl, hydroxy-carboxylate, carboxylate, sulfonate and phosphonate) and the stereochemistry of their hydroxyl groups.The different retardations induced by the organic molecules studied on the hydration of the mineral compound responsible of the final properties of OPC, tricalcium silicate, were related to the characteristics of the organic admixtures. The interactions of these organic compounds such as their adsorption on calcium silicate hydrate (C-S-H) and their complexation with calcium, hydroxide and/or silicate ions in solution were identified in systems at equilibrium and correlated to the retarding effect generated by the organic molecules on the hydration of tricalcium silicate.The impact of hexitols which differ from one another in the stereochemistry of their hydroxyl groups on the dissolution-precipitation process of the hydration of tricalcium silicate was studied. The influence of these polyols on the hydration of a calcium aluminate and calcium sulfate mixture was explained by their adsorption on ettringite and AFm as well as by their ionic complexation in solution. Finally, this study focused on the consequences of the interactions of hexitols with ettringite and aluminate ions in solution on the hydration of the silicate phases present in OPC

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26

Dalas, Florent. "Influence des paramètres structuraux de superplastifiants sur l'hydratation, la création de surfaces initiales et la fluidité de systèmes cimentaires modèles." Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS019/document.

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L’emploi d’adjuvants fluidifiants est courant pour tout béton. Ceci permet d’améliorer les propriétés rhéologiques à l’état frais: la fluidité initiale et son maintien pendant les 2-3 premières heures de la vie d’un béton. La compréhension de ce mécanisme d’action est encore partielle pour les PCP (copolymères greffés). Ici, le but a été de tester l’hypothèse selon laquelle l’évolution de la quantité de PCP adsorbé par unité de surface minérale instantanée explique quantitativement l’évolution temporelle de la fluidité au cours de la période d’ouvrabilité.Sur un système inerte (calcite), nous avons confirmé que la fluidité est bien gouvernée par l’adsorption: à même adsorption surfacique, la fluidité de la pâte est quasiment identique quelle que soit la structure du PCP. Par ailleurs sur un système inerte (calcite ou ettringite), la modification de la fonction ionique du PCP fournit une solution pour améliorer la résistance de l’adsorption à la variation de la concentration en sulfates.Deux techniques ont été utilisées pour mesurer l’aire interfaciale au cours de l’hydratation d’un système réactif modèle (aluminate tricalcique, gypse, hémihydrate et calcite): l’adsorption de N2 et la relaxométrie du proton de l’eau. L’adsorption du PCP par unité de surface réelle a été calculée et corrélée à la fluidité de la pâte. La relation simple fluidité/adsorption n’est plus vérifiée ici. La présence de PCP a un impact sur l’hydratation du système et l’augmentation de l’étendue de la surface minérale associée. Les PCP vont augmenter la surface spécifique de l’ettringite qui précipite en modifiant sa morphologie. Cet effet est plus marqué quand la densité de greffage du PCP diminue
Nowadays the use of superplasticizers admixtures becomes unavoidable for concrete. It allows enhancing the rheological properties at the fresh state: the initial flow and slump retention during the 2-3 first hours of the life of a concrete. The understanding of this mechanism is still partly elucidated for PCE (grafted copolymers). The aim of this thesis was to challenge the assumption of the evolution of the adsorbed amount of PCE per instantaneous mineral surface unit as origin of the fluidity temporal evolution during the workability period.On an inert system (calcite), we confirmed that the fluidity is mainly governed by the adsorption level. Thus for a same surface adsorption density, the fluidity of the paste is roughly similar whatever the structure of the PCE. On an inert system also (calcite or ettringite), the modification of the anionic function provides a technological way to improve the resistance of the adsorption against the variation of the sulfate ions concentration.The surface area of a reactive model system (tricalcium aluminate, gypsum, hemihydrate and calcite) has been measured by two techniques during the workability period: the N2 adsorption (BET) and the water proton relaxometry (RMN). The PCE adsorption per surface unit has been calculated and analysed in link with the fluidity of the paste. In that case, the simple relation, shown on the inert system, is not verified because the presence of PCE has also an impact on the hydration and on the extent of the surface area. Especially PCE lead to increase the surface by changing the morphology of ettringite. The specific surface area of ettringite increases when the grafting density of PCE decreases

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27

Lowys, Marie-Pierre. "Comportement physico-chimique de suspensions de fibres cellulosiques : rôle des additifs." Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10195.

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Ce travail porte sur la caracterisation physico-chimique de suspensions aqueuses de microfibrilles de cellulose (mfc) issues de la transformation des betteraves sucrieres, seules ou en presence d'additifs. La composition chimique des suspensions meres de mfc est determinee : elles sont composees de 86% de cellulose pure, les 14% restant etant des pectines, des hemicelluloses et des sels. Les proprietes ioniques des mfc sont ensuite etudiees par differentes techniques (conductimetrie, potentiel d'ecoulement, potentiel zeta). L'etat de dispersion des suspensions a ete caracterise par des mesures rheologiques en ecoulement et de sedimentation, qui ont mis en evidence l'importance du mode de dispersion et de la concentration en mfc sur la stabilite des suspensions. Nous avons montre l'existence d'une concentration critique c* au-dela de laquelle les suspensions ont un comportement de type gel. Des echantillons de mfc seches sous forme de film ne permettent pas de recuperer les proprietes rheologiques initiales lors de la remise en suspension. L'etude du comportement rheologique dynamique, montre que la remise en suspension est satisfaisante si un additif anionique est ajoute aux mfc avant sechage. L'etude de l'adsorption et de la desorption de ces additifs et des observations en microscopie de fluorescence, montrent que l'adsorption se fait de maniere uniforme sur toute la surface des mfc, mais que les interactions mises en jeu sont faibles, totalement reversibles. L'adsorption depend fortement de la charge et de la structure chimique de l'additif, mais pas de sa masse molaire. Ces resultats conduisent a l'hypothese de la formation d'un film interfacial d'additif anionique parfaitement hydrosoluble autour des mfc lors du sechage, permettant la remise en suspension et la recuperation des proprietes rheologiques de la suspension initiale. Certaines proprietes des suspensions de mfc ont ete comparees a celles de suspensions d'une cellulose bacterienne.

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Soumbo, Marvine. "Adsorption des protéines sur les surfaces de couches minces de silice seules ou additivées de nanoparticules d'argent : impact sur les forces d'adhésion de Candida albicans." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30258.

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Dans de nombreux secteurs, l'adhésion microbienne sur les surfaces est la source de multiples impacts négatifs. Cette étape est considérée comme préliminaire au développement de biofilm et peut être influencée par la présence d'un film conditionnant engendré par l'adsorption des protéines sur la surface. Ainsi, les stratégies visant une intervention au moment de la phase initiale d'adhésion représentent une approche appropriée pour prévenir la bio-contamination des surfaces et nécessitent une compréhension à l'échelle moléculaire. Dans ce contexte, les matériaux nanocomposites à base de nanoparticules d'argents (AgNPs) et de silice (SiO2) apparaissent comme des outils pertinents. Ce travail de thèse porte sur l'utilisation de substrats nanocomposites possédant une monocouche d'AgNPs exposées à leurs surfaces ou enterrées dans une matrice de SiO2plasma à une distance contrôlée de quelques nanomètres de la surface afin d'explorer, d'une part l'adhésion de protéines modèles (Sérum Albumine Bovine, DsRed et Fibronectine) et leurs changements conformationnels et d'autre part, la cinétique de détachement de la levure Candida albicans dans les différentes conditions. Les AgNPs sont bien connues pour leurs activités antimicrobiennes et présentent de plus, des propriétés optiques permettant de détecter des signatures moléculaires à leurs proximités. Suite à l'application de la spectroscopie Raman exaltée de surface en utilisant les couches nanocomposites à base d'AgNPs, la détection de trois conformations de la DsRed (protéine fluorescente rouge) adsorbée et déshydratée sur les substrats plasmoniques a été possible. Les résultats obtenus montrent que les changements conformationnels des protéines avec une forte cohérence interne sont réversibles. En parallèle, nous avons évalué la dynamique d'organisation et le comportement de la SAB, de la Fn et de la DsRed en contact avec des couches minces de silice ou additivées d'AgNPs. Les mesures des angles de contact des gouttelettes de différentes concentrations protéiques ont montré une interaction hydrophile croissante avec la SiO2th thermique. L'hydrophobicité de surface est modifiée pour les substrats nanocomposites. L'épaisseur et les propriétés optiques des couches protéiques adsorbées ont été évaluées par ellipsométrie spectroscopique. En fonction de la concentration de protéines dans solution les résultats montrent l'évolution d'une monocouche protéique non continue et non dense vers une monocouche plus compacte et plus complexe pour des concentrations élevées.[...]
Microbial adhesion on solid surfaces is the source of multiple negative impacts in many areas. This step is considered prior to biofilm formation. It might be influenced by the presence of a conditioning layer generated after protein adsorption on the surface. Thus, strategies to act during the initial phase of microbial adhesion represent an appropriate approach to prevent bio-contamination of solid surfaces. However, they require understanding of the underlying mechanisms at the molecular level. In this context, nanocomposite materials based on silver nanoparticles (AgNPs) and silica (SiO2) appear as relevant tools. This thesis focuses on the use of nanocomposite thin layers containing a plan of AgNPs exposed on their surfaces or buried in a SiO2plasma matrix at a controlled distance of a few nanometers from the surface in order to explore, on the one hand, the adhesion of model proteins (Bovine Serum Albumin, DsRed and Fibronectin) and their conformational changes and secondly, the kinetics of detachment of the yeast Candida albicans under the different conditions. AgNPs are well known for their antimicrobial activities but also for their optical properties allowing detection of molecular signatures at their proximities. Following the application of surface-enhanced Raman spectroscopy using AgNP-based nanocomposite layers, the detection of three conformations of DsRed (red fluorescent protein) adsorbed and dehydrated on plasmonic substrates was achieved. The obtained results show that the conformational changes of proteins with a strong internal coherence are reversible. In parallel, we have evaluated the dynamics of the organization and behavior of BSA, Fn and DsRed in contact with thin silica layers or silica layers containing AgNPs. Contact angle measurements of droplets of different protein concentrations showed increasing hydrophilic interaction with thermal SiO2th. For the nanocomposite layers, the surface hydrophobicity is modified. The thickness and optical properties of the adsorbed protein layers were evaluated by spectroscopic ellipsometry. Depending on the protein concentration in solution the results show the evolution of a non-continuous and non-dense protein monolayer to a more compact and complex monolayer at high concentrations. [...]

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Demir-kivrak, Hilal. "Synthesis And Characterization Of Ethanol Electro-oxidation Catalysis." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12613887/index.pdf.

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ABSTRACT SYNTHESIS AND CHARACTERIZATION OF ETHANOL ELECTRO-OXIDATION CATALYSIS Demir-Kivrak, Hilal Ph.D., Department of Chemical Engineering Supervisor : Prof. Dr. Deniz Ü
ner Co-supervisor : Dr. Sadig Kuliyev October 2010, 196 pages In this study, the role of defects, the role of Sn in relation to defects, and the role of oxide phase of tin in ethanol electro-oxidation reaction were investigated. Firstly, adsorption calorimetry measurements were conducted on monometallic (1%Pt, 2%Pt, and 5%Pt) and bi-metallic (5% Pt-Sn) &gamma
-Al2O3 supported Pt catalysts. It was observed that while saturation coverage values decreased, intermediate heats remained same for Pt-Sn catalysts by the increasing amount of tin. The effect of particle size was investigated on Pt/C (pH=5), Pt/C (pH=11) catalysts at different scan rates. At high scan rates (quite above diffusion limitations), current per site activities were nearly the same for 20% Pt/C (E-Tek), Pt/C (pH=11), and Pt/C (pH=5) catalysts, which explained as electro-oxidation reaction takes place at the defects sites. Furthermore, the effect of support on ethanol electro-oxidation was investigated on CNT supported Pt catalyst. Results indicate that only the metal v dispersions improved ethanol electro-oxidation reaction and support did not have any effect on ethanol electro-oxidation reaction. Results on the 20% Pt-Sn/C (15:1 to 1:1 Pt: Sn atomic ratios) and 20% Pt-SnO2/C (6:1 and 1:1) catalysts indicated that ethanol electro-oxidation activity increased by increasing tin amount. For 20% Pt-Sn/C catalysts, Pt-Sn (6:1)/C indicated best activity. On the other hand, 20% Pt-SnO2 (6:1)/C catalyst was better than Pt-Sn (6:1)/C in terms of ethanol electro-oxidation activity due to the fact that there was low contact between Pt and tin oxide particles.

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Kababji, Ala'a Hamed. "Effects of Diluent Addition and Metal Support Interactions in Heterogeneous Catalysis: SiC/VPO Catalysts for Maleic Anhydride Production and Co/Silica Supported Catalysts for FTS." Scholar Commons, 2009. https://scholarcommons.usf.edu/etd/2035.

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This work begins with an introduction to catalysis focusing on heterogeneous systems and surface science phenomena. A study on the partial oxidation reaction of n-butane to maleic anhydride (MA) is presented in the first part. MA supplies are barely adequate for market requirements due to continued strong demand. Only slight improvement in catalytic performance would be welcome in the industrial community. The vanadium phosphorus oxide (VPO) catalyst was used in this work. The reaction is highly exothermic and the need to properly support the catalyst, not only for good dispersion but adequate heat dissipation is of crucial importance. For this, alpha-SiC commercial powders were used in synthesizing the catalyst due to its high thermal conductivity. Up to 25% MA yields were obtained and the reaction temperature was lowered by up to 28% using SiC/VPO mixed catalysts. The second part of this work is focused on the Fischer-Tropsch synthesis (FTS) process using cobalt silica supported catalysts. The main objective is the production of synthetic ultra high purity jet fuel (JP5). This is a very timely topic given the energy issues our world is facing. Almost all aspects of the FTS process have been extensively studied, however the effects of calcination temperature and silica support structure on the catalyst performance are lacking in literature. The catalysts were prepared using various silica supports. The catalysts had different drying and calcination temperatures. It was found that lower support surface area and calcination temperature catalysts exhibited higher activity due to lower support cobalt phase interaction. Co/silica catalysts calcined at 573K showed the highest CO conversion and the lowest CH4 selectivity. Catalysts prepared with 300m²/g support surface area exhibited 79.5% C5+ selectivity due to higher reducibility and less metal support interaction. The properties and performance of various prepared catalysts in both VPO and Co/silica systems are characterized by FTIR, XRD, BET, GC and XPS techniques. Theoretical FTS deactivation by sintering calculations and SiC/VPO particle temperature gradient calculations are presented as well. Finally, conclusions and future work on improving the yield and selectivity and scaling up the bench top setups are also presented.

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Li, Chuanping. "Rheological Properties of Aqueous Nanometric Alumina Suspensions." Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/835308-5NQETg/webviewable/.

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32

Vanlerberghe, Aldo. "Mise au point et applications de la spectrométrie IR-TF à l'analyse par réflexion externe et diffuse des films formés par adsorption et frottement des additifs de lubrifiant sur surfaces métalliques." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37618999w.

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Dubois-Clochard, Marie-Claude. "Dispersants en milieu organique synthèse et étude physico-chimique de dispersants pour carburants et lubrifiants." Paris 6, 1998. http://www.theses.fr/1998PA066479.

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Au cours de son fonctionnement, des dépôts issus du carburant et du lubrifiant se forment dans différents organes d'un moteur. En général, ces dépôts affectent quatre fonctions essentielles que sont le dosage du carburant, l'admission du mélange air/carburant, la lubrification et la combustion. Ces dépôts peuvent conduire à une dégradation des performances et de l'agrément de conduite, à une augmentation de la consommation et des émissions de polluants et peuvent occasionner la destruction du moteur. Pour remédier à ces problèmes, des additifs détergents-dispersants sont utilisés dans les carburants et les lubrifiants pour empêcher ou réduire l'adhésion des dépôts sur les surfaces métalliques et prévenir l'agrégation des dépôts. Les additifs étudiés possèdent une structure de polymère tensioactif de type polyisobutenylsuccinimide. Dans un premier temps, des additifs de structure peigne ont été synthétisés. Leur performance ainsi que leur mode d'action ont pu ensuite être évalués par comparaison de ces additifs avec des additifs classiques de structure dibloc. La comparaison de ces structures a été possible grâce à différentes techniques physico-chimiques telles que l'élaboration d'isothermes d'adsorption en milieu organique, la microcalorimétrie, la diffusion des neutrons, l'évaluation de la taille des agrégats par diffusion dynamique de la lumière en milieu noir et la rhéologie. Ces additifs s'adsorbent par leur partie hydrophile de type polyamine sur les acides de surface du noir de carbone pris comme modèle des dépôts moteur et sur les fonctions alumine de la poudre d'aluminium prise comme modèle de la paroi métallique du moteur. Lorsque la température augmente, ils ont tendance à s'adsorber davantage sur le noir de carbone que sur l'aluminium. Leur affinité pour la surface solide croit avec la longueur croissante de la chaine hydrophile ou par le passage d'une structure dibloc a une structure peigne. Aux faibles concentrations en additif, cette adsorption a l'interface solide/hydrocarbure est irréversible du fait du caractère polymère de la partie hydrophile. Après la formation d'une monocouche plus ou moins compacte suivant l'encombrement de la partie hydrophile de l'additif sur la surface solide, apparait aux fortes concentrations un accroissement de la quantité adsorbée. Cette augmentation serait provoquée par un phénomène d'hémi-micellisation inverse. Les interactions additifs-monocouche sont faibles puisque le phénomène est totalement réversible. La structure peigne améliore l'efficacité dispersante de la structure dibloc en contraignant les parties hydrophiles à se serrer les unes contre les autres diminuant ainsi leur encombrement sur la surface solide et favorisant l'étirement des chaines hydrophobes. La monocouche étant par conséquent plus compacte et plus stable d'après l'évolution de l'entropie du système, la stabilité colloïdale par répulsion hydrophobe des suspensions de noir de carbone stabilisées par des additifs de structure peigne est d'autant plus performante qu'un abaissement de la viscosité de la suspension est observée par rapport aux structures diblocs.

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Etahiri, Abderahman. "Caractérisation diélectrique des phénomènes d'adsorption des collecteurs et des déprimants sur les pulpes minérales conductrices : application à la galène et à la chalcopyrite." Nancy 1, 1993. http://www.theses.fr/1993NAN10128.

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Les techniques diélectriques haute fréquence permettent de préciser in situ la nature des interactions adsorbat/adsorbant lors des processus de flottation, grâce à la détermination de la permittivité complexe. L'analyse des paramètres fréquence, force ionique, granulométrie et température relatives aux pulpes minérales permet de préciser les conditions in situ des variations éventuelles apportées par l'adsorption d'un collecteur (xanthate, amine, sulfonâtes) ou d'un déprimant (dextrine, hydroxydes de nickel et de cobalt). Il est clairement mis en évidence que l'adsorption du xanthate sur la galène est de type chimique (formation de -pbx) alors qu'elle est de type physique dans le cas de la chalcopyrite (formation de x2). Dans le premier cas, on observe une diminution de la constante et de la perte diélectriques, qui est faible dans le second. La grande sensibilité de la technique permet d'étudier les phénomènes d'adsorption au cours de la monocouche. Elle permet également d'analyser en détail les phénomènes de coadsorption xanthate/dextrine et xanthate/hydroxyde de nickel et de cobalt qu'il était difficile d'étudier in situ jusqu'à présent

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Liang, Ho-Cheng, and 梁賀程. "The Investigation of Adsorption Characteristics for VOCs on Activated Carbon with Metal Oxide Additive." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/23377484043363702755.

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碩士
長庚大學
化學工程研究所
86
In this research, the pores of activated carbon were initially impregnated with a concentrated solution of the metal salt, then the activated carbon are dried and calcined . The n-type ZnO and p-type NiO of semiconducting metal oxide were selected in the pretreatment processes. The ICP、 SEM and BET specific area instruments were used to identify the difference in the chemical and physical characteristics of activated carbon and activated carbon with metal oxide. The thermal desorption characteristics of MEK、HA、BEN、 TOL and HEX on activated carbon and activated carbon with various metal oxide(ZnO and NiO) were tested by use of TGA instrument. The Coats and Redfern method and differential method and least square method were used for getting the parameters (rate constant、activated energy、reaction order ) of the basic reaction kinetics equation, . The result showed the Coats and Redfern method had a better fitting curve. It also showed that the thermal desorption temperatures of MEK on activated carbon with metal oxide were significanty decreased. For HA, it found that that the thermal desorption temperatures of activated carbon with ZnO were increased. Form the evaluation of LUB tests, the activated carbon with 0.1M NiO had the best LUB for the polar solvents(MEK and HA).

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Fritz, Susanne. "MD-Simulationen zur Adsorption von Additiven aus wässriger Lösung auf Calciumsulfat-Flächen." Doctoral thesis, 2014. https://tubaf.qucosa.de/id/qucosa%3A22995.

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Die Adsorption von Additiven an den Oberflächen eines Kristallisates wird als eine hauptsächliche Ursache für die Beeinflussung von Kristallwachstum und Morphologie angesehen und spielt bei vielen Kristallisationsprozessen eine entscheidende Rolle. Gerade für die Calciumsulfate, die im Millionen-Tonnen-Maßstab jährlich in Deutschland verarbeitet werden, stellt der Additiv-Einsatz einen Hauptkostenfaktor dar, während gleichzeitig die Additivwirkung mechanistisch nicht ausreichend gut verstanden und damit derzeit nicht vorhersagbar ist. Zur Erlangung eines besseren Verständnisses wurden mit Hilfe von molekulardynamischen Computersimulationen die Prozesse in den Grenzflächen zwischen festen Calciumsulfaten und wässriger Additivlösung auf atomarer Ebene analysiert. Wesentlicher Untersuchungsschwerpunkt war dabei die Rolle des polaren Lösungsmittels Wasser auf die Wechselwirkung zwischen verschiedenen ionischen Additivspezies und den Salzkristallen.:1. Einleitung und Zielsetzung 1 2. Literatur 6 2.1. Kristallstrukturen der Calciumsulfate 7 2.2. Kristallmorphologie und relevante Kristallﬂächen 10 2.2.1. Kristallwachstum und Morphologie der Calciumsulfate 10 2.2.2. Theoretische Methoden zur Morphologievorhersage 13 2.2.3. Morphologievorhersage für die Calciumsulfate 18 2.3. Struktur von Mineral-Wasser-Grenzﬂächen 20 2.3.1. Experimentelle Untersuchungen 20 2.3.2. Simulationen 25 2.4. Morphologiebeeinﬂussung der Calciumsulfate durch Additive 26 2.4.1. Additive für Calciumsulfate und deren Wirkungsweise 26 2.4.2. Beeinﬂussung der Gipsmorphologie durch Zitronensäure und Aminosäuren 28 2.5. Stand der Technik von Adsorptionssimulationen 31 2.5.1. Methodenüberblick 31 2.5.2. Molekulardynamische Adsorptionssimulationen 33 2.5.3. Modellierungen und Simulationen der Calciumsulfat-Additiv- Wechselwirkung 44 3. Methodik 47 3.1. Simulationsbasis 49 3.1.1. Randbedingungen und Annahmen 49 3.1.2. Simulationsmethoden und -parameter 51 3.1.3. Kraftfeld 55 3.1.4. Erstellen von Simulationsboxen 60 3.2. Simulationen zur Morphologievorhersage 65 3.2.1. Durchgeführte Simulationen 66 iiiInhaltsverzeichnis 3.2.2. Berechnung der Morphologie im Vakuum 68 3.2.3. Berechnung der Morphologie in Lösung 69 3.2.4. Zusammenfassung 72 3.3. Simulationen der CaSO 4 -Wasser-Grenzﬂäche 74 3.3.1. Durchgeführte Simulationen 74 3.3.2. Charakterisierung der Oberﬂächenstabilität 75 3.3.3. Strukturelle Charakterisierung der Hydratationsschichten 77 3.3.4. Kinetische Charakterisierung der Hydratationsschichten 82 3.3.5. Thermodynamische Charakterisierung der Hydratations- schichten 83 3.3.6. Zusammenfassung 87 3.4. Simulation der Adsorption 89 3.4.1. Durchgeführte Simulationen 89 3.4.2. Berechnung der Adsorptionsenergie 103 3.4.3. Berechnung der Freien Adsorptionsenergie 106 3.4.4. Zusammenfassung 112 4. Ergebnisse und Diskussion 114 4.1. Morphologievorhersage und Flächenauswahl 115 4.1.1. Die Morphologie im Vakuum 115 4.1.2. Die Morphologie in Lösung 123 4.1.3. Flächenauswahl 126 4.2. Die Mineral-Wasser-Grenzﬂäche 127 4.2.1. Oberﬂächenstabilität 127 4.2.2. Strukturelle Charakterisierung der Hydratationsschichten 133 4.2.3. Kinetische Charakterisierung der Hydratationsschichten 153 4.2.4. Thermodynamische Charakterisierung der Hydratations- schichten 162 4.2.5. Einﬂuss der Simulationsmethodik 166 4.3. Die Adsorption 167 4.3.1. Einﬂuss des Lösungsmittels 167 4.3.2. Einﬂuss des Additivs 176 4.3.3. Einﬂuss der Fläche 186 4.3.4. Einﬂuss der Simulationsmethodik 201 5. Zusammenfassung und Ausblick 211 ivInhaltsverzeichnis Abkürzungsverzeichnis V-1 Literaturverzeichnis V-6 Abbildungsverzeichnis V-34 Tabellenverzeichnis V-38 A. Methoden A-1 A.1. Erstellen von Simulationsboxen mit Kristallschichten A-2 A.1.1. Randbedingungen A-2 A.1.2. Erstellen der Elementarzelle A-3 A.1.3. Erstellen der Oberﬂächenelementarzelle A-3 A.2. Voruntersuchungen zur Adsorption A-8 A.2.1. Ausgangssituation A-8 A.2.2. Finden energetisch günstiger Konformationen A-11 A.2.3. Berechnung der Freien Adsorptionsenergie A-13 A.2.4. Berechnung der Adsorptionsenergie A-23 A.3. Clusteranalyse A-24 B. Tabellen B-1 C. Abbildungen C-1

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Huang, Fu-Chuan, and 黃福全. "Effect of Adsorption Characteristics for MEK and Acetic Acid on Activated Carbon with Metal Oxide Additive." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/98191061388601764865.

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碩士
淡江大學
水資源及環境工程學系
86
In this research, fourteen various various adsorbents (AC,AC-400℃,AC-0.1M Zn (No3)2,AC,0.5M Zn (NO3)2,AC-1.0M Zn(NO3)2,AC-0.1M ZnO,AC-0.5M ZnO,AC-1.0M ZnO, AC-0.1M Ni(NO3)2, AC-0.5 Ni (NO3)2, AC-1.0M Ni(NO3)2, AC-0.1M NiO, AC-0.5M NiO, AC-1.0M NiO) were prepared. The analysis results of specific surace area, micropore volume, and pore diameter among the fourteen adsordents were not verysignificant differences. The BET surface areas were 808-967m2/g, and the Langmuir surface areas were 1073-1300m2/g. Form the analysis results of the ICP, when AC was impregnated with various concentration solutions of Zn nitrate and Ni nitrate, Zn and Ni contents of activated carbons were increased very conspicuous. 　　For the adsorption tests of MEK vapor, the adsorption capacity on AC-0.1M NiO was the best among the fourteen adsorbents. It was increased more about 13% than that of AC, Comparison of the length of unused bed (LUB) and adsorption zone (Hz) of AC and AC-0.1M NiO showed a decrease of about 65% and 59％ for AC-0.1M NiO Moreover, the adsorption rate constants of AC and AC-0.1M NiO were 1500 min-1 and 3907 min-1, respectively. For the adsorption tests of Acetic Acid, Comparison of the length of unused bed (LUB) and adsorption zone (Hz) of AC and AC-0.1M NiO showed a decrease of about 39% and 26% for AC-0.1M NiO. Moreover, the adsorption rate constants of AC and AC-0.1M Nio were 842 min-1 and 3397 min-1, respectively. The higher Kv value of the adsorbent was, the narrower adsorption zone of the adsorbent was, and the higher the affinity of the adsorbent (AC-0.1M NiO) to adsorb MEK and Acetic Acid was.

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38

(8812424), Tejesh Charles Dube. "Experimental and Modeling Study of Gas Adsorption in Metal-Organic Framework Coated on 3D Printed Plastics." Thesis, 2020.

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Metal-organic frameworks (MOFs) are a class of compounds consisting of metal ions or clusters coordinated to organic ligands in porous structure forms. MOFs have been proposed in use for gas adsorption, purification, and separation applications. This work combines MOFs with 3D printing technologies, in which 3D printed plastics serve as a mechanical structural support for MOFs powder, in order to realize a component design for gas adsorption. The objective of the thesis is to understand the gas adsorption behavior of MIL-101 (Cr) MOF coated on 3D printed PETG, a glycol modified version of polyethylene terephthalate, through a combined experimental and modeling study. The specific goals are: (1) synthesis of MIL-101 (Cr) MOFs; (2) nitrogen gas adsorption measurements and microstructure and phase characterization of the MOFs; (3) design and 3D printing of porous PETG substrate structures; (4) deposition of MOFs coating on the PETG substrates; and (5) Monte Carlo (MC) modeling of sorption isotherms of nitrogen and carbon dioxide in the MOFs.

The results show that pure MIL-101 (Cr) MOFs were successfully synthesized, as confirmed by the scanning electron microscopy (SEM) images and X-ray diffrac- tion (XRD), which are consistent with literature data. The Brunauer-Emmett-Teller (BET) surface area measurement shows that the MOFs samples have a high cover- age of nitrogen. The specific surface area of a typical MIL-101 (Cr) MOFs sample is 2716.83 m2/g. MIL-101 (Cr) also shows good uptake at low pressures in experimental tests for nitrogen adsorption. For the PETG substrate, disk-shape plastic samples with a controlled pore morphology were designed and fabricated using the fused de-

position modeling (FDM) process. MOFs were coated on the PETG substrates using a layer-by-layer (LbL) assembly approach, up to 30 layers. The MOFs coating layer thicknesses increase with the number of deposition layers. The computational model illustrates that the MOFs show increased outputs in adsorption of nitrogen as pres- sure increases, similar to the trend observed in the adsorption experiment. The model also shows promising results for carbon dioxide uptake at low pressures, and hence the developed MOFs based components would serve as a viable candidate in gas adsorption applications.

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39

Chen, Yi-Chieh, and 陳逸傑. "The Study of Adsorption Characteristics for the Binary VOCs of MEK and Toluene on Activated Carbon and Activated Carbon with Metal Oxide Additive." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/28310203748943796247.

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碩士
長庚大學
化學工程研究所
87
In this research, adsorption breakthrough characteristics of binary vocs system with methyl-ethyl-ketone(MEK) and toluene (TOL) on activated carbon are investigated. At first the isothermal adsorption curves and adsorption kinetic parameters of MEK and TOL in the single component system are determined. Using single-component isotherm equations, IAST, and the parameters of the binary adsorption system, breakthrough curves of the binary adsorption can be calculated by the used Nader Vahdat model. The predictability of the model is tested with a set of adsorption data in the binary system. The result shows that the sum of adsorption capacity of MEK and TOL for binary system is also lower than the sum of adsorption capacity of MEK and TOL in the single-component system. For breakthrough curve prediction, the weak adsorbate, MEK, is breakthrough early. According to the competition adsorption effect, adsorbed MEK on the activated carbon will be replaced by stronger adsorbate, TOL. Adsorbed MEK will desorb from the activated carbon and goes into stream. Therefore, outlet concentration of MEK will increase. To determine the adsorption equilibrium time, the concentration of TOL is more important factor than that of MEK. The more inlet concentration of TOL, the faster adsorption equilibrium of the system arrives. The predictions of start time and the maximum concentrations of the breakthrough curves by the model are well for the adsorption binary system. But the predictions for the breakthrough curves are poor. The parameters, adsorption capacities and k of TOL , in the binary system need to be corrected for this model.

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Li, Huei-Yi, and 李慧儀. "Effect of Fiber Properties and Protein Additives on Adsorption and Hydrolysis by an Endoglucanase." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/71181565554995306569.

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碩士
國立臺灣大學
森林環境暨資源學研究所
100
In recent years, due to the rapid industrial development, a great deal of fossil energy is used. It is one of ways that ultimate biomass to generate energy for solving the problem of fossil energy dried up gradually. One of the main steps in bio-refining procedures for cellulose in biomass turns into fermentable sugars through the hydrolysis, then transfer to other chemicals such as alcohol by microbial. Due to a high degree of crystallinity of cellulose and closely packed accumulation of saccharification, hydrolysis becomes very difficult. Lignocellulose is the most abundant renewable resources on the Earth, this paper is to explore the relationship between the lignocellulosic enzyme adsorption and hydrolysis. Eucalypt pulps deal with sulfate process, and then sieving into different sizes, then proceeding low-temperature adsorption experiments and high-temperature hydrolysis. The cases of the experimental results, the fully bleached pulp achieve Fibercare maximum adsorption than unbleached pulp at low temperature (4oC); the unbleached pulp achieve maximum adsorption capacity at high temperature (40 oC) hydrolysis circumstances, whereas. In addition, comparison of protein adsorption and enzymatic hydrolysis yield of rice straw steam explosion pulp, R-100 gets larger protein adsorption values. Besides, molecular weight changes and reducing sugar released were monitored for digestibility of the samples. To explore the interaction of cellulase and pulp on different conditions among lignin contents and adding BSA and Lysozyme. We observed that irrelevant proteins preferentially adsorbed on pulp surface with higher lignin contents than cellulase, and the addition of BSA or Lysozyme strengthened the above trend. Studies have shown that surfactants such as BSA and Lysozyme preferentially adsorbed to the lignin of the pulp fiber. Hydrolyzed protein adsorb correctly in the target cellulose, thus increasing the efficiency of the hydrolytic enzymes, changing the hydrolysis mechanism.

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黃瀅華. "A study on the adsorption of sulfur dioxide with sugar mill mud and additives." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/22965857116446042962.

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Ching-Hong, Cheng, and 鄭慶弘. "A Study on the Enhancement of Adsorption of SO2 by MgCO3 Pellet with Additives." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/80438749159990065979.

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碩士
國立臺灣科技大學
化學工程研究所
83
The adsorption of SO2 by the pellet of MgCO3 and additives have been studied by a thermogravimeteric analyzer along with X-ray diffractometer , surface area meter and scanning electron microscope . The study was divided into two parts . The first part was on the effects of the different additives upon the sorption reactivity and final conversion . In the second part , MgCO3 was mixed with Fe2O3 . The effects of the following variables on the reactivity were studied : the amount of Fe2O3 , the grain size of Fe2O3 , calcination temperature and sulfation temperature . Results of the first part indicated that Fe2(SO4)3 , FeSO4 , K2SO4 , Cu(NO3)2 , KNO3 , K2CO3 , NaHCO3 , Na2CO3 , and Fe2O3 accelerated the adsorption while Li2 SO4 , Fe(NO3)3 , Al2O3 , TiO2 , SiO2 , SnCl2 , NaCl , KCl and CaCl2 inhibited the adsorption . Results of the second part showed that the reaction rate could be increased by increasing the amount of Fe2O3 , decreasing the grain size of Fe2O3 , increasing the sulfation temperature or decreasing the calcination temperature . The reason for the enhancement of adsorption of SO2 by MgCO3 with Fe2O3 is probably due to the catalytic effect of Fe2O3 on the oxidation of SO2 to form SO3 which is more easily captured than SO2 by MgO .

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Hwa, Hwang Ying, and 黃瀅華. "A Study on the Adsorption of Sulfur Dioxide with the Sugar Mill Mud and Additives." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/90387570711583500301.

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碩士
國立臺灣科技大學
化學工程研究所
81
The adsorption of sulfur dioxide by sugar mill mud with additives has been studied in a thermo- gravimeteric analyzer along with scanning electron microscope. The study was divided into two parts. The first was on the effect of the different additives upon the sorption reactivity. The second was on the experimental conditions upon the sorption reac- tivity. Results of the first part indicated that the clinker of the Hsiehho power plant was the best promoter,and all the wastes of the power plant(fly ash, boiler clinker , bottom ash , oil ash ) were good promoter,too. The other promoters having been found were: Ferric Sulfate,Ferric Oxide,Aluminum Oxide,Copper Nitrate, Potassium Nitrate,Ferrous Sulfate,Potassium hydrogen sulfate, Titanium dioxide Potassium Carbonate,Potassium Chloride,Sodium hydr -ogen and Silica. The additives inhibit the rea -ction were Calcium Chloride,Stannic Chloride,Sodium Chloride,Sodium Carbonate,Potassium sulfate,Lithium sulfate,Ferric Nitrate. The results of the second part show that the reaction rate could be increased by decreasing the weight of solid sample,increasing the concentration of SOand the sulfation temperature. The reaction rate was also increased by the gas flow rate. However ,the rate levelled off when the gas flow rate was hi- gher than a certainvalue. Rate equation regressed based on the data obtained by the experiments were found to be: dWad 0.3037 -0.1744 -------- = 0.33735 Cso2 W dts T Vg (-------------) (-------------) exp(-1.67E4ts) 1+1.533X10T 1+6.068X10Vg The equation is applicable in the following ranges : sulfation temperature 923-1223 K,gas flow rate 2.5E -6-1.33E-5cubic meter/ ses,weight of solid sample 2E-5- 1.1E-4 Kg,concentration of Sulfur dioxide 1000-5000ppm ,calcination time 1 hr and sulfation time 3hr.

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44

Chieh, Chou Ming, and 周明杰. "Adsorption and ozone oxidation of MEK vapor on activated carbon with TiO2 addition." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/43174588353815103546.

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碩士
長庚大學
化工與材料工程研究所
93
In this research, the activated carbon was impregnated with TiO2. The depositions of TiO2 catalytic nanoparticles can be achieved. The properties of specific surface area, and pore volume of the adsorbent were analyzed. An adsorption process in combination with an ozone oxidation process is studied for the control of MEK vpor. The adsorption apparatus and TGA instrument were used to measure the adsorption characteristics, such as adsorption capacity, adsorption rate, isotherm adsorption, and breakthrough curve, and kinetic data of adsorption and thermal desorption for MEK vapor. In addition, the extent to which TiO2 supported affects activated carbon for adsorption and thermal desorption was also evaluated. From the experimental results, the specific surface area of AC-TiO2 was decreased and micropore diameter was increased. But, the fractal dimensions were not changed significant. The reason was that when AC is impregnated with TiO2, the pores of activated carbon may be blocked and hinders the favorable geometrical arrangement of adsorbed molecules over the surface. The adsorption capacities of 300 ppm MEK vapor on AC-TiO2 were 0.054 -0.2631 g/g at 30 – 90 ℃ and were more than those of AC by 5-14%. The destructive efficiency of MEK vapor on AC or AC-TiO2 with 1000 ppmv O3 both are about 10-43%, even if the adsorption bed is exhausted. Thermal desorption tests revealed that the Tm of the activated carbon with TiO2 additive significantly decreased by about 10-30℃ in the thermal desorption process. The apparent activation energies of adsorbents for MEK in the thermal desorption process were 22 - 32 kJ/mole. The influences of TiO2 additive on the activated carbon were attributed to both increases of the apparent activation energy and the rate constant. But, the influences of O3 on the adsorption were attributed to both decreases of the apparent activation energy and the rate constant.

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45

Saravanan, L. "Surface Chemical Studies On Oxide And Carbide Suspensions In The Presence Of Polymeric Additives." Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1386.

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46

Maina, Paul. "Effects of hydrating additives on materials used in desulphurisation." 2011. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000898.

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M. Tech. Mechanical engineering.
Acid deposition is caused by the emission of acidic gases, for example, nitrogen oxides and sulfur dioxide. Nitrogen oxide emissions can be controlled by the proper selection of equipment and operating conditions. Sulfur dioxide on the other hand, can be cleaned by means of procombustion, combustion or post-combustion techniques; the latter being the most effective. The objective of this study is to find suitable additives which will augment the reactivity of lime towards FGD (flue gas desulfurization), while at the same time being easily available at a low price. Zeolite based sorbents yielded the highest reactivity, and all additives, except iron waste, had pozzolanic materials as their main reactive compounds.

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47

Hsiao, Ming-Chang, and 蕭明昌. "Influences of Ferric Hydroxide Prepared with addition of Citrate/Silicate on Adsorption of As(V)/Cd(II)." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/07665070797399656616.

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碩士
國立成功大學
化學系專班
96
This study is to discuss with the surface characteristics, crystalline identification and inner structural changes of the Ferric Hydroxide which are prepared with pure Fe(Ⅲ), citrate/Fe(Ⅲ) and silicate/Fe(Ⅲ) solutions at different molar ratios. This study is also to compared the adsorption capabilities of these Ferric Hydroxide serving as the adsorptive materials in containing As(V)/Cd(II) solutions through adsorption experiment.. By means of the XRD identification analysis, the synthetic iron oxides of pure Fe(Ⅲ) and silicate/Fe(Ⅲ) are non-crystal Ferric Hydroxide, but the synthetic iron oxide of citrate/Fe(Ⅲ) is crystal Ferric Hydroxide. The inner structural will be changed which prepared with citrate/Fe(Ⅲ) solutions It can not find change of functional groups by using FT-IR in the Cd(II) adsorption system. We can only refer to this system is not Specific adsorption. It can find change of functional groups by using FT-IR in the As(V) adsorption system. And it shows the similar trend with adsorption amount of arsenic. We can refer to this system is Specific adsorption.

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48

Cardoso, Liliana Farinha. "Remediação de solos contaminados com metais pesados - combinação de nanotecnologias e aditivos naturais." Master's thesis, 2020. http://hdl.handle.net/10316/90170.

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Dissertação de Mestrado Integrado em Engenharia do Ambiente apresentada à Faculdade de Ciências e Tecnologia
O aumento da degradação do planeta causado pelas atividades humanas é uma preocupação crescente a nível mundial. Nos últimos anos, devido ao crescimento populacional e à expansão contínua da produção industrial, das atividades agrícolas e da exploração mineira, houve um aumento de contaminações por compostos químicos perigosos em diversos locais do planeta.O objetivo do presente estudo é investigar a aplicação de nanopartículas (nanotubos de carbono de paredes múltiplas) e aditivos naturais mais sustentáveis, tais como a argila na remediação de solos contaminados com metais pesados. Os solos objeto de estudo são o saibro e argila e o solo mole do Baixo Mondego, contaminados artificialmente por metais pesados (níquel e zinco).Numa primeira fase, é testada a utilização de surfactantes (SDBS- Pluronic F-127) na dispersão de nanotubos de carbono de paredes múltiplas (MWCNTs) e estudada a capacidade destes últimos em imobilizar os metais pesados da mistura (saibro e argila) contaminados por metais pesados, realizando ensaios de adsorção em solo. Os resultados mostraram que a afinidade de adsorção era muito elevada, sendo os metais pesados adsorvidos quase na totalidade.Na segunda fase, é investigada a aplicação da mistura de solo e argila como materiais com capacidade para imobilizar os metais pesados no solo mole do Baixo Mondego contaminado, através de ensaio de adsorção em solo. Recorreu-se a dois métodos distintos de análise, como a introdução da mistura de solo e da argila como barreira reativa / filtro e/ou como aditivos naturais. Os resultados obtidos mostram que os dois métodos conseguem adsorver quase na totalidade os metais pesados, sendo que a argila apresenta os melhores valores. Todos os sistemas aplicados nesta dissertação constituem alternativas sustentáveis e promissoras para o tratamento de solos contaminados por metais pesados.
There is a growing worldwide concern related to the degradation of the planet caused by human activities. In recent years, due to population growth and the continuous expansion of industrial production, agricultural activities, and mining, there has been an increase in contamination by dangerous chemical compounds in various locations on the planet.The aim of the present study is to investigate the application of nanoparticles (multi-walled carbon nanotubes) and more sustainable natural additives (e.g. clay) in the remediation of soils contaminated with heavy metals. The soils used in this study are grit and clay and the soft soil of Baixo Mondego, artificially contaminated by heavy metals (nickel and zinc).In the first phase, the use of surfactants (SDBS-Pluronic F-127) in the dispersion of multi-walled carbon nanotubes (MWCNTs) is tested in the mixture (i.e. gravel and clay) to understand the heavy metals immobilization capacity using soil adsorption tests. The results showed that the adsorption affinity was very high. After the analysis, heavy metals were almost completely adsorbed. In the second phase, the application of the mixture of soil and clay as materials capable of immobilizing heavy metals is investigated in the contaminated low Mondego soft soil, through soil adsorption testing. Two different methods of analysis were used, such as the introduction of the mixture of soil and clay as a reactive barrier/filter and/or as natural additives.The results obtained show that both methods are able to adsorb almost all heavy metals, however, clay presented best values. All systems applied in this dissertation are sustainable and promising alternatives for the treatment of soils contaminated by heavy metals

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49

Recalde, Lummer Nils Michael [Verfasser]. "Adsorption behavior and effectiveness of AMPS-based cement fluid loss additives at high temperature and in combination with lignosulfonate and biogums / Nils Michael Recalde Lummer." 2011. http://d-nb.info/101110783X/34.

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Dissertations / Theses on the topic 'Additive adsorption'

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