Dissertations / Theses: 'Aluminum hydrolysis'

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Madem, Akhil. "Enhancing Reaction System for Hydrolysis on Aluminum." Thesis, KTH, Kemiteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-266447.

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A range extender in a battery electric vehicle supplements the existing drive system as an add-on module. Range extenders can comprise of any combination of conventional fuel, battery or fuel cell driven modules. The idea of a sub-system changes with the type of range extender. In this work, hydrogen generation is studied, a fuel is used to power the range extender via a fuel cell.The thesis presents the work in progress for development of the sub-system for a range extender based on on-board production of hydrogen for automobiles. Several aspects of chemistry play equally pivotal role in control, hassle-free operation and safety of the system. Aftertreatment of the fuel by-products is the notorious issue that limits the reusing the reactor effecting the range extender. Along with this, reducing the reaction time with minimal usage of fuel is investigated. Both of these pressing issues are resolved correspondingly to an extent with the addition of several chemicals. In addition, with the help of characterization techniques, a robust circular economy outlook of the range extender system has been initiated. En distansförlängare i ett eldrivet fordon kompletterar det befintliga drivsystemet som en tilläggsmodul. Distansförlängaren kan vara olika kombinationer av konventionella bränsle-, batteri- och bränslecelldrivna moduler. Utformningen av de övriga delarna av undersystemet beror på vilken distansförlängare som används. I detta arbete drivs distansförlängaren av en bränslecell, bränslet till bränslecellen genereras i distansförlängaren. Avhandlingen presenterar det pågående arbetet för utvecklingen av undersystemet hos en distansförlängare. Undersystemet baseras på ombordsproduktion av väte för bilar. Flera aspekter av kemi spelar en lika viktig roll i kontroll, problemfri drift och säkerhet. Efterbehandling av bränslets biprodukter är det ständiga problemet som begränsar reaktorns återanvändbarhet vilket påverkar distansförlängaren. Tillsammans med detta undersöks minskning av reaktionstiden med minimal användning av bränsle. Båda dessa pressande problem löses i en utsträckning med tillsatsen av flera kemikalier. Dessutom har en robust cirkulärekonomisk syn på distansförlängaren utvecklats med hjälp av olika karakteriseringstekniker.

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Saukkoriipi, J. (Jaakko). "Theoretical study of the hydrolysis of aluminum complexes." Doctoral thesis, University of Oulu, 2010. http://urn.fi/urn:isbn:9789514261831.

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Abstract This thesis focuses on the molecular-level chemistry of the solvation of aluminum salts. Fundamental aspects such as, structural characteristics of the aluminum molecules, hydrolysis, acidity, solvation structure, effect of counter ions, and chemical stability are discussed herein. Static computations augmented with the conductor-like screening model (COSMO) were used to investigate hundreds of planar and cyclic configurations of dimeric, trimeric, tetrameric, and pentameric aluminum complexes. Car–Parrinello molecular dynamics (CPMD) calculations were used to expand investigations to aqueous environments. This thesis consists of four articles and one additional article. The first paper focuses on the structural analysis of the hydrolysis products of AlCl3 · 6H2O. Dimeric, trimeric, and tetrameric aluminum (chloro)hydroxides were investigated in both gas and liquid phase. The liquid environment was modeled by using COSMO. The second and the additional paper concentrate on the chemistry of aluminum sulfate complexes. The second article focuses on identifying hydrolysis products of AlCl3 · 6H2O in the presence of sulfate (H2SO4). The additional paper focuses on the structural characteristics of the hydrolysis products of Al2 (SO4)3 · 18H2O. Structural information was deduced from the ESI MS results with the aid of computational methods. Detected cationic structures closely resembled the aluminum chlorohydrate analogues introduced in the first paper. The third and fourth articles are devoted to the hydrolysis, stability, and dynamics of dimeric and pentameric aluminum (chloro)hydroxides in aquatic environments. During the CPMD simulations, several spontaneous associative hydration reactions were detected in the primary hydration shell of the complexes. Dimeric aluminum chlorohydrates were detected to be stable in liquid conditions, whereas the pentameric aluminum complexes experienced significant topological changes during the simulations. Constrained simulations were used to reveal the role of chloride ions in the hydrolysis processes of dimeric complexes. The effect of the empirical van der Waals corrections to the dynamics of the simulations was also tested for the pentameric system. The results of this thesis showed unequivocally that computational chemistry provides effective tools for structural analysis of inorganic complexes such as, aluminum chlorohydrates and sulfates in both gas and liquid phase. In addition, calculations provided answers to the anomalies detected in the experiments. Hence, theoretical methods are highly recommended to be used alongside with conventional experimental methods in the interpretation of the aluminum species in aqueous solutions and to widen the overall chemical perspective of the hydrolysis of aluminum salts.

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White, George Norman. "Measurement of hydrolysis, polymerization and complexation in dilute aluminum solutions." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53664.

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The nature of chemical reactions taking place during the titration of dilute Al solutions in the presence of either chloride or sulfate were examined by refining the apparent Al hydrolysis products assuming the presence of solution species with n (OH/Al mole ratio) equal to 1, 2, 2.5, 3 and 4. The second and third hydrolysis products for Al were refined by comparison of calculated titration patterns to those observed for 10⁻³, 10⁻⁴ and 10⁻⁵ M Al in 1 M, 0.1 M and 0.01 M KCl. A large degree of polynuclear character of Al solutions was found even at Al concentrations as low as 10⁻⁵ M. The n value and size of the polynuclear complexes are affected by Al concentration. The concentration constant, pQ₁₃ is found to be at least 17.4-17.7. It is concluded that the mononuclear Al(OH)₂ species is never significant. Use of statistical analysis of the data and graphical methods did not result in consistent data for polymer size determinations. The lower pQ values for mononuclear Al hydrolysis are explained by the structural instability of the mononuclear complexes. The bond strengths required for the bonds in the second and third hydrolysis complexes are often larger than those allowed for octahedral coordination. For that reason, the pQ values would be lower than calculated by extrapolation between the stable first and fourth hydrolysis constants. A new polynuclear complexation mechanism for Al is proposed to account for the high concentration of high n value polynuclear species in the titration refinements. The proposed linear l double chain structure has a structure consistent with boehmite and diaspore. This structure differs from the linear single chain and ring based polynuclear structures by the presence of rows of three coordinated oxygens in the bond central chain and rows of two and one coordinated oxygens along the plane edges. A rearrangement of internal charge in this structure is proposed in which part of the charge is removed from the three coordinated oxygens to result in an uncharged hydroxyl with the charge shifted to the one coordinated site neutralizing the hydroxyl. This results in a general formula for the polynuclear structure of (Al(OH)₃)x(Al(OH)₂)₂²⁺. This structure results in a higher n value for a lower number of Al than does the other polynuclear complexation schemes and therefore explains the presence of high n value polymers in unaged Al solutions which would have required polymers of greater than a hundred Al cations. The observed presence of a second Al plateau on titration patterns with Al concentrations greater than 5 x10⁻⁵ M could not be the result of the onset of precipitation as earlier proposed. It is proposed that at a pH in the 6 to 7 range, a change of some of the one coordinated sites on the edge of the larger polynuclear and precipitant structures from water to hydroxyls results in a change in net edge charge from net positive to net negative which causes an increased rate of crystal growth due to the unlike charge between the edges and the smaller polynuclear and mononuclear complexes. The refinement of Al titration data in K₂SO₄, provide pQ values one to three pQ units lower than those obtained from equivalent KCl solutions. A catalytic mechanism is proposed in which Al polymerization is facilitated by the formation of mononuclear Al hydroxy sulfate complexes which combine together to form nonsulfate containing polynuclear complexes. The increased hydrolyzed concentration and lower ionic charge resulting from these complexes would increase the rate of polymerization in these systems. Evidence for the presence of mononuclear hydroxy sulfate complexes comes from the better fit for titration patterns in sulfate systems which would not have been observed for increased polymerization alone. Ph. D.

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Chen, Minyi Carleton University Dissertation Chemistry. "The structure binding relationship of aluminum hydrolysis species with hydrophilic gels." Ottawa, 1993.

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Abeysinghe, Samangi. "Keggin-type aluminum nanoclusters: synthesis, structural characterization and environmental implications." Thesis, University of Iowa, 2012. https://ir.uiowa.edu/etd/2430.

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Hydrolysis products of aluminum that exist in aqueous solutions play an important role in controlling the fate and transport of contaminants and are also used for coagulants to purification of wastewater streams. Adsorption of contaminants such as heavy metals and organics are widely recognized, but the molecular level understanding of the mechanism of action has not been clearly defined. In this research we present the crystallization, structural characterization and chemical characterization of three novel Keggin-type aluminum polycations including ((Al(IDA)H2O)2(Al30O8(OH)60(H2O)22)(2,6 NDS)4(SO4)2Cl4(H2O)40) (Al32-IDA),[(Cu(H2O)2(µ2-OH)2)2(Al2(µ4-O)8(Al28(µ2-OH)50(µ3-OH)6(H2O)26(2,6-NDS)9(H2O)52]-(CuAl30) and [(Zn(NTA)H2O)2(Al(NTA)(µ2-OH)2)2(Al30(µ2-OH)54(µ3-OH)6(µ4-O)8(H2O)20(2,6-NDS)5(H2O)64]-(ZnAl32) where IDA = iminodiacetic acid, NTA- Nitrilotriacetic acid, and 2,6 NDS = 2,6 napthalene disulfonate. These compounds are the first ever reported Keggin-type aluminum species that have been functionalized with organics and heavy metal cations. Structural characterization of these compounds was done by means of single crystal X-ray diffraction along with FTIR, TGA, SEM/EDS and PXRD techniques for chemical characterization. This study provides more insight into the coagulation process and can be employed in developing optimized coagulants for enhanced water purification.

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Li, Peng. "Innovative process solutions towards recycling of salt cake from secondary aluminum smelting." Doctoral thesis, KTH, Materialens processvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101074.

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To offer better solutions for the recycling of salt cake from secondary aluminum melting, several innovative investigations were carried out based on hydrometallurgical and pyrometallurgical views. Thermal diffusivity measurements as a function of temperature on salts-Al composites having various compositions (0, 2, 4, 6, 8, 10, 12wt pct metallic Al) were carried out. Its attempt to derive theoretical relationships between aluminium contents in the salt-Al composites and the thermal conductivities so that these would serve as calibration curves for industrial samples taken out from secondary aluminium re-melting at a later stage. The AlN hydrolysis behavior in NaCl solution was investigated by immersing pure AlN powder in deionized water, 0.3mol/l NaCl aq, 0.6mol/l NaCl aq and NaCl solution respectively with CO2 bubbling at 291K. The results showed that AlN powder underwent enhanced hydrolysis in NaCl aq than that in deionized water, while, the introduction of CO2 was found to hinder the hydrolysis even in the presence of NaCl. The characterization of the products after hydrolysis was carried out using XRD, SEM and TEM analyses. It was shown that the hydrolysis process included a slow-reaction period involving the dissolution of aluminum hydroxide layer around raw AlN particle, followed by the precipitation of aluminum hydroxide gel and the crystallization of boehmite, bayerite and gibbsite. The effects of sodium chloride concentration on the hydrolysis behavior are presented. The leaching process in CO2-saturated water showed that, at a solid to liquid ratio of 1:20 and 3h at 291K, the extraction of Na and K from the dross could be kept as high as 95.6% and 95.9%, respectively. At the same time, with continuous CO2 bubbling, the mass of generated NH3 during the leaching process decreased significantly, also the escaping NH3 gas decreased from 0.25mg in pure water down to <0.006mg. The above results showed that the introduction of CO2 causes hindrance to the hydrolysis of AlN, meanwhile, effective absorption of ammonia. The plausible mechanisms for the observed phenomena are discussed. The concept of the leaching of the salt cake by carbonated water and the consequent retention of AlN in the leach residue opens up a promising route towards an environment-friendly recycling process for the salt cake viz. recovery of the salts, utilization of CO2 and further processing of the dross residue, towards the synthesis of SiAlON from the leach residues. In alternative route to the processing of salt cake, the ammonia gas evolved by hydrolysis of AlN was collected by CO2-saturated water during water leaching at 373K. The products, i.e. ammonium carbonates which are free of chlorides, has application as a fertilizer, besides that, this method also has the advantage of fixing carbon from CO2, which is the subject of many investigations around the world. The oxidation behavior of composites SiMgAlON phases (β-SiAlON, MgAlON and 15R) synthesized from the residue during the leaching treatment of salt cake and corresponding synthetic samples was investigated in air by thermogravimetric measurements. The oxidation studies reveal the effects of impurities, namely, Fe2O3 and CaO present in the salt cake residue. From the view of kinetics, the addition of Fe2O3 brings a lower activation energy and more aggressive oxidation. The additive of CaO caused the shrinkage during the synthesis and liquid formation during the oxidation above 1673K, thus retard the oxidation rate. The impurities of CaO and Fe2O3 in the leaching residue can result in an aggressive oxidation at low temperature and a protective oxidation at temperatures above the eutectic point. From the view of phase evolution, with the progress of oxidation, the composition of the material being oxidized moved towards the Al2O3-rich corner of MgO-Al2O3-SiO2 or CaO-MgO-Al2O3-SiO2 phase diagrams relevant to SiMgAlON composite. At lower temperatures, the addition of Fe2O3 and CaO facilitated the formation of cordierite and anorthite, respectively. With the increasing of temperature, islands of silicate melt were formed dissolving these oxides, with the liquidus temperature getting lowered as a consequence. The liquid phase formed engulfed the adjacent solid phases providing strong mobility for the cations and enabling the crystal growth. As a result, intermediate products, i.e. cordierite, anorthite, spinel, which formed earlier during oxidation are found to get dissolved in the liquid phase. QC 20120912

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Masion, Armand. "Chimie moléculaire et colloïdale des complexes organiques de l'aluminium III partiellement hydrolysés." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL028N.

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Les acides organiques modifient considérablement le déroulement de l'hydrolyse de l'aluminium par blocage des oligomères intermédiaires entre le monomère et le tridecamère. Les précipités présentent une structure variable suivant l'échelle d'observation

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Sarpola, A. (Arja). "The hydrolysis of aluminium, a mass spectrometric study." Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514285578.

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Abstract This thesis is focused on the hydrolysis of aluminium, the polymerisation of the hydrolysis products, and how these can be monitored by mass spectrometric methods. The main aim of this research is to figure out how the aqueous speciation of aluminium changes as a function of pH (3.2–10), concentration (1–100 mM), reaction time (1s–14d), and counter anion (Cl-, SO42-, HCOO-). The method used was electrospray mass spectrometry. The results showed more variable speciation than those suggested earlier. The main species were Al2, Al3, and Al13, which were found in all of the conditions under scrutiny. The effect of pH was the most remarkable of all the parameters researched. The formation of large highly charged complexes was strongly dependent on it. Also the Al-concentration in the bulk solution had a clear effect on speciation: in dilute solutions there were more protonated ligands and less attached counter anions. This could mean that the species in more diluted bulk solutions had fewer different states of charge. Reaction time caused only minor changes to speciation in the initial pH: there was slightly more variation of a certain sized species in the aged solution. In elevated pH, the birth of important Al13 oligomers was time dependent. The effect of the counter anion was tremendous. In a chloride environment the speciation was rich and diversified. With sulphate the speciation was limited to solid- like compounds, and the variation of single-sized species was almost lacking. The formate as a counter anion caused most surprising results; the charge of aluminium in some studied complexes was lowered from the common 3+ to 1+. If this reaction also occurs in natural circumstances, the uses of aluminium formate would be wide. The results can be utilised in following the progress of dissolution, the mobilization and toxicity of aluminium in natural waters, as well as in water purification, and in reaching minimal chemical contamination levels in sludge as well as in aqueous waste.

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Santos, Camila Sanzovo Barbosa dos. "Aspectos de sustentabilidade em um processo de produção de hidrogênio com a reutilização do alumínio." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/3217.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Levando em consideração medidas para diminuir os efeitos das mudanças climáticas e tecnologias que auxiliam na segurança energética, esta dissertação tem como tema central o estudo da geração de gás hidrogênio como energia alternativa. O gás hidrogênio é um vetor energético com reduzidas emissões de poluentes na atmosfera se comparados com as fontes tradicionais existentes de energia. No entanto, estudos e pesquisas sobre suas potencialidades e viabilidades, tanto técnicas quanto socioeconômicas e ambientais, precisam ser desenvolvidas para amadurecimento tecnológico. O objetivo desta dissertação é analisar a produção de hidrogênio por hidrólise alcalina, com a reutilização de alumínio, correlacionando-a aos aspectos da sustentabilidade. Parte-se de um processo já conhecido e bem difundido no meio científico o qual será analisado e discutido suas possibilidades como tecnologia alternativa para produção de energia. O método empregado para a análise foi bibliográfico junto com o levantamento de dados primários em laboratório de um processo com requerimento de patente, dando caráter de pesquisa exploratória e descritiva. Os principais resultados técnicos foram: vazão média 77,53 ml.(min.g) -1 de H2, com pureza de 84,20%. Em seguida, realizou-se uma análise econômica, em moeda nacional, real R$/(m³.H2) e dólar norte-americano US$/kWh, comparando com outros estudos que determinaram o custo de produção em processos de geração deste tipo do gás. Estruturou-se uma matriz de aspectos e impactos que ilustram os potenciais efeitos na geração de energia. Concluiu-se que à geração de gás hidrogênio por hidrólise alcalina com a reutilização de alumínio secundário contribui para a visão direcionada para a sustentabilidade do planeta, podendo ser uma alternativa energética descentralizada. Taking into account measures to reduce the effects of climate change and technologies that help energy security, this dissertation focuses on the study of generation of hydrogen gas as alternative energy. Hydrogen gas is an energy vector with reduced emissions of pollutants into the atmosphere compared to existing traditional sources of energy. However, studies and research on their potentialities and viabilities, both technical and socioeconomic and environmental, need to be developed for technological maturation. The objective of this dissertation is to analyze the production of hydrogen by alkaline hydrolysis, with the reuse of aluminum, correlating it to the aspects of sustainability. It starts from a process already known and well diffused in the scientific environment which will be analyzed and discussed its possibilities as alternative technology for energy production. The method used for the analysis was bibliographic along with the collection of primary data in the laboratory of a process with patent application, giving character of exploratory and descriptive research. The main technical results were: average flow 77.53 ml (min.g) -1 .H2, with a purity of 84.20%. Then, an economic analysis was performed in national currency, real R $ / (m³.H2) and US$ / kWh, comparing with other studies that determined the cost of production in this type of generation processes. gas. A matrix of aspects and impacts was drawn up illustrating the potential effects on energy generation. It was concluded that the generation of hydrogen gas by alkaline hydrolysis with the reuse of secondary aluminum contributes to the vision aimed at the sustainability of the planet, and can be a decentralized energy alternative.

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Benyattou, Abdelkader. "Thermohydrolyse de solutions d'aluminium III, conditions d'apparition de phases solides : caractérisations physico-chimiques des précipités." Lyon 1, 1994. http://www.theses.fr/1994LYO10071.

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La thermohydrolyyse, obention d'une phase solide par ebullition prolongee d'une solution initialement homogene, peut etre une technique interessante. Elle assure une bonne reproductibilite et limite la dispersion des proprietes texturales des solides obtenus. Des hydroxysulfates appartenant a la famille des alunites peuvent se former par thermohydrolyse de solutions de sulfate d'aluminium. L'influence de la composition des solutions a ete etudiee. Il est clairement etabli que l'alunite se forme en presence des cations na#+ ou nh#4#+ mais non pas en presence de li#+. Le rendement de precipitation croit lorsque les rapports so#4#2#-/al#3#+ avec (na#+ -o) et na#+ (ounh#4#+)al#3#+ augmentent. Une diminution rapide du ph apparait en meme temps que la temperature augmente: a l'ebullition le ph se stabilise pendant toute la duree de l'hydrolyse. L'utilisation des constantes d'hydrolyse et de complexation generalement admises, l'exploitation des spectres de la rnn de #2#7 al qui montrent le role du complexe al(h#2o)#5so#4#+, ont conduit a proposer un mecanisme dans lequel se forme d'abord l'anion al#3(h#2o)#8(os)#6(so#4)#2#-. Ensuite il se deshydrate et precipite avec l'alcalin, si ce dernier est suffisamment volumineux. La composition des solides obtenus depend etroitement de celle de la solution mere, la variation des parametres cristallins peut etre directement lies a la concentration des ions sodium de la solution. Par pyrolyse a l'air a environ 900c, les alubates conduisent a l'oxyde d'aluminium, al#2o#3 pour la natroalunite et al#2o#3 pour l'ammonialunite. La precipitation simultanee des ions mg#2s+ et al#3#+ par cette technique conduit a ph 12, a l'hydroxyde double mg#4al#2(08)#1#4, 3h#2o. Les conditions de synthese tres dures entrainent la formation de phases parasites. La modification du rapport al#3/mgh#2#+ entre 0,5 et 0,8

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Soames, Mark. "Sol-gel routes to platinum, platinum-tin and platinum-potassium reforming catalysts." Thesis, Brunel University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311280.

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D’Oliveira, Elisabete Castro. "Origem da acidez da nascente do rio Campo Belo, maciço do Itatiaia - R.J." Niterói, 2017. https://app.uff.br/riuff/handle/1/5382.

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Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-12-18T14:58:25Z No. of bitstreams: 1 Dissertação realmente corrigida.pdf: 2600370 bytes, checksum: f6dfd5312d899b3cc7513282683ff5be (MD5) Made available in DSpace on 2017-12-18T14:58:25Z (GMT). No. of bitstreams: 1 Dissertação realmente corrigida.pdf: 2600370 bytes, checksum: f6dfd5312d899b3cc7513282683ff5be (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ Pode-se considerar a química das águas naturais dividida em duas categorias de reações mais comuns: as reações ácido-base e as de oxidação-redução. Os fenômenos ácidobase e de solubilidade controlam o pH e as concentrações de íons inorgânicos, resultando em composição química variada de acordo com as condições bioclimáticas. A origem da acidez de uma água natural pode estar relacionada à geoquímica e ao aporte de matéria orgânica e nutrientes, fenômeno frequente em ambientes que apresentam drenagem sob turfeira. As turfeiras são ambientes especiais para estudos relacionados com a dinâmica da matéria orgânica, elas contribuem para o sequestro global de carbono, além de funcionarem como reservatórios de água. Nesse contexto, o objetivo desse trabalho foi analisar a correlação da matéria orgânica e da interação água-rocha com a acidez observada na nascente do rio Campo Belo, situada à 2419 m de altitude, no Maciço do Itatiaia. Para isso, foram coletadas amostras de água e solo, submetidas à analise dos parâmetros físico-químicos in situ e análise dos íons maiores e elementos traço em laboratório. Os resultados encontrados foram utilizados para a realização da modelagem para especiação de íons em água e tratamento estatístico multivariado, que mostraram que a disponibilidade do alumínio no solo está correlacionada com as variações do pH ao longo do perfil. A liberação do alumínio aumenta a acidez do sistema através da hidrólise ácida da água, o que por sua vez, favorece o aumento da desmineralização e lixiviação de bases, favorecendo a concentração e retenção do alumínio no solo. Embora a matéria orgânica não seja responsável pela acidez, a presença da turfa é fator imprescindível para a manutenção da acidez, pois atua como sequestrador de bases ao formar complexos com as substâncias húmicas, além de exercer papel tamponante no sistema. The chemistry of natural waters can be divided in two more common reaction categories: acid-base reactions, and oxidation-reduction reactions. Acid-base and solubility phenomena control the pH and the inorganic ions concentrations, which result in diverse chemical composition, according to bioclimatic conditions. Acidity origin of natural waters can be related to its geochemistry and to organic matter and nutrient supplies, which are frequent phenomena in environments that present drainage underneath turf. Turfs are special environments for studies related to organic matter dynamic, they contribute to carbon global sequestration, besides functioning as water reservoirs. In that context, the aim of this work was to analyse the correlation between organic matter and water-rock interaction with the acidity observed at the Campo Belo river spring, located at 2419 m of altitude, at the Itatiaia massif. For that, water and soil samples were collected, and analised in terms of their physical-chemical parameters, in situ, and also analysis of the major ions and trace elements in laboratory. The observed results were used in an ion speciation modeling in water, and multivariate statistical analysis, that showed that the availability of aluminum in the soil is correlated to the pH variations along the soil profile. The liberation of aluminum increases the system acidity through acidic hydrolysis of water, which, in turn, promotes the increase of the demineralization and leaching of basis, favoring the concentration and retention of the aluminum of the soil. Despite the organic matter is not responsible for the acidity, the presence of turf is an indispensable factor for the maintenance of the acidity, since it acts as basis sequestrant as it forms complexes with humic substances, besides playing a role in buffering the system.

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Fournier, Agathe. "Interactions of pure aluminium hydrolytic species Keggin polyoxocations and hydroxide with biologically relevant molecules." Thesis, Nottingham Trent University, 2008. http://irep.ntu.ac.uk/id/eprint/99/.

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The general purpose of this thesis is concerned with the intricate interactions of pure aluminium species with biomolecules. Pure aluminium reference systems (aluminium monomers, Keggin aluminium polyoxocations - Al13 and Al30, and aluminium hydroxide suspensions) were used for systematic mechanistic studies of the sol-gel transformation of aqueous solutions of aluminium-ions into aluminium (oxy) hydroxides induced by the addition of a 'soft base' - Trizma-base, which does not ionize fully in an aqueous solution. The conversion proceeds via forced hydrolysis-condensation of aluminium-ions into molecular clusters, structural conversion of aluminium Keggin-like polynuclear clusters into nanoparticles of aluminium (oxy) hydroxide, aggregation of primary nuclei of aluminium (oxy) hydroxide into larger clusters and finally the 'arrested growth' of the aggregates with the formation of the three-dimensional gel network. The next part of the study concentrated on the development and the optimisation of a potentiometric method for the determination of the 'formal' hydrolysis ratio of aluminium-containing solutions. The method made it possible to establish the aluminium speciation of the selected systems. The interactions of aluminium species with three model biomolecules - lactic acid, hen egg lysozyme and porcine mucin - were investigated. Aluminium and lactic acid underwent a strong coordination in aqueous solutions, with increasing concentrations of lactic acid appearing to force all the aluminium species initially introduced to convert into monomers and dimers as a result of an acidic hydrolysis. Subsequently, the resulting hydrolysed products formed new aluminium-lactate chelates. The evolution of both the inorganic and biomolecular phases of the lysozyme-aluminium systems demonstrated that specific charge-stabilised bioinorganic assemblies involving aluminium species and lysozyme formed. The chemical and structural alterations of the protein on interaction with the inorganic species showed that the interactions occurred. The interactions of aluminium with mucin appeared predominantly electrostatically driven. The formation of the aluminium-mucin entities modified the native conformation of the protein: initially organised into b-sheet structure, mucin, within the complexes, acquired a more compact organisation involving intermolecular bonding. Furthermore, in the case of the aluminium hydroxide systems, the established complexes were ordered into sheet-like structures. Although the level of concentrations of aluminium and biomolecules exceeded those normally found in the human body and environmental media, we believe that the better understanding of aluminium species-biomolecule interactions would be of benefit to those working in the biomedical and environmental sciences.

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Allouche, Lionel. "Etude par RMN des mécanismes de formation par hydrolyse des polycations d'aluminium." Université Louis Pasteur (Strasbourg) (1971-2008), 2001. http://www.theses.fr/2001STR13222.

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Molis, Elisabeth. "Dissolution en suspension et en position d'intercalation des formes hydrolysées de l'aluminium en interaction avec des ligands organiques." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL123N.

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Les études concernant l'évolution chimique et structurale d'espèces d'aluminium en présence de salicylate ont été menées en combinant plusieurs méthodes d'analyses telles que l'électrophorèse, les spectroscopies infrarouges et RMN, les méthodes thermiques et de diffusion de rayonnement. Dans les cas étudiés, les agrégats d'Al13, la gibbsite et la montmorillonite intercalée par l'Al13, ces méthodes nous ont permis de mettre en évidence des changements structuraux important, du à la dissolution de l'aluminium en fonction de la concentration en ligand organique. L’interaction entre les espèces d'aluminium hydrolyse et le salicylate révèle deux phénomènes: la complexation et la dissolution. L’étude de la complexation nous a permis de mettre en évidence la nature et le type de complexation entre l'aluminium et le salicylate. Aux faibles concentrations en ligand, la complexation se fait sur les sites les plus réactifs, les sites charges Al-OH2+. Elle a pour effet de neutraliser le système et donc de condenser la structure des agrégats. Aux fortes concentrations en ligand, la complexation se poursuit sur les sites neutres, ce qui provoque la rupture des liaisons Al-O. La nature du complexe entre l'aluminium et le salicylate est un bidentate impliquant les oxygènes du groupement carboxyl. Ce complexe observé par IR est identique pour les agrégats et pour la gibbsite. La complexation entre le salicylate et l'aluminium a pour conséquence la dissolution des espèces étudiées. La caractéristique la plus marquante, observée pour les trois cas étudiés, est le fait que la dissolution ne commence que lorsque l'on apporte un excès de charge dans le système. La dissolution provoque des modifications structurales à plusieurs échelles sur les agrégats et la montmorillonite-Al13 mais pas sur la gibbsite: échelle locale, semi-locale et à grande distance. La cinétique de dissolution est quant à elle très différente selon la nature et l'environnement de l'aluminium

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16

Chamoun, Rita. "Elaboration de films catalytiques co-alumine par dépôt électrophorétique pour l'hydrolyse du NaBH4 : développement du procédé dans une perspective de valorisation d'argiles naturelles du Liban comme supports de catalyseurs." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10167.

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L’hydrolyse spontanée du NaBH4 en milieu aqueux est une réaction lente nécessitant l’emploi d’un catalyseur pour l’accélérer. Nous présentons ici l’élaboration de catalyseurs Co supporté sur αAl2O3 mis forme de films, plus appropriés pour des applications nécessitant un démarrage/arrêt à la demande de la génération d’H2. Les films sont déposés sur un substrat Cu par dépôt électrophorétique (DEP). Par ailleurs, des catalyseurs Co supporté sur différentes argiles naturelles (Kaolinite, Illite-A et Illite-B) en provenance du Liban ont été élaborés. Le Co a été déposé sur αAl2O3 par six voies différentes : 1. Imprégnation de Co sur film αAl2O3 ; 2. Précipitation de Co sur film αAl2O3; 3. Electrodéposition du Co sur film αAl2O3; 4. Codéposition du Co et de αAl2O3; 5. Codéposition de nanoparticules de Co et de αAl2O3 et 6. DEP de Co-αAl2O3. La voie 6 est la meilleure pour l’élaboration des films 1, 5, 10 et 15 mass.% Co-αAl2O3. Ces films (homogènes) et les catalyseurs Co-αAl2O3 ont été comparés pour leur réactivité et l’étude cinétique a donné des énergies apparentes d’activation identiques: 51.3 et 52.7 kJ mol-1, respectivement.Ensuite, des catalyseurs de 1, 5, 10 et 15 mass.% Co-argile ont été élaborés selon le même procédé que celui de Co-αAl2O3. Ces catalyseurs ont montré une réactivité pour l’hydrolyse du NaBH4, donnant notamment des énergies apparentes d’activation de 58.8, 51.5 et 58.1 kJ mol-1 pour 15 mass.% Co-Kaolinite, (Illite-A) et (Illite-B) respectivement. De plus, des films homogènes de 1, 5, 10 et 15 mass.% Co-Kaolinite ont été déposés avec succès sur Inox par DEP. Cette étude a montré le potentiel de ces argiles naturelles comme supports de catalyseur NaBH4 hydrolysis reaction is slow in aqueous medium. Therefore, it can be accelerated by addition of a catalyst. In this work, catalytic films of Co supported over αAl2O3 have been synthesized since they are more convenient for applications requiring generation of H2 on demand. Co-αAl2O3 films were deposited on Cu plates by electrophoretic deposition method (EPD). Furthermore, catalysts of Co supported over different types of natural clay (Kaolinite, Illite-A and Illite-B) provided from Lebanon were also synthesized.Co was deposited over αAl2O3 following six routes: 1. αAl2O3 film impregnation; 2. Co precipitation over αAl2O3 film; 3. Co electrodeposition over αAl2O3 film; 4. Coelectrodeposition of Co from CoCl2 and αAl2O3; 5. Coelectrodeposition of Co nanoparticles and αAl2O3 and 6. EPD of Co-αAl2O3. Route 6 was found to be the best one for the fabrication of homogeneous films of 1, 5, 10 and 15 wt.% Co-αAl2O3. A comparative study on the reactivity of Co-αAl2O3 films and powder catalysts was done and the kinetic study gave similar values of the apparent activation energies: 51.3 and 52.7 kJ mol-1, respectively. Moreover, Co was supported over clay with the same method used for Co-αAl2O3. 1, 5, 10 and 15 wt.% Co-clay catalysts were tested for the hydrolysis reaction and the apparent activation energies obtained were as follows: 58.8, 51.5 and 58.1 kJ mol-1 for 15 wt.% Co-Kaolinite, (Illite-A) and (Illite-B) respectively. Homogeneous films of 1, 5, 10 and 15 wt.% Co-Kaolinite were successfully deposited over Inox substrate by EPD. It was concluded from this work that natural clays can be used as potential supports for Co catalysts in the hydrolysis of NaBH4

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BERGAMASCHI, VANDERLEI S. "Preparação e caracterização de catalisadores de metais de transição suportados em zircônia. Uso na reforma a vapor do etanol para obtenção de hidrogênio." reponame:Repositório Institucional do IPEN, 2005. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11359.

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Made available in DSpace on 2014-10-09T12:51:04Z (GMT). No. of bitstreams: 0 Made available in DSpace on 2014-10-09T14:07:38Z (GMT). No. of bitstreams: 1 11129.pdf: 7996300 bytes, checksum: d14b1b217192ca316a3d971bede18997 (MD5) Tese (Doutoramento) IPEN/T Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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18

Piot, Jean-Marie. "Contribution à l'étude de la production et de la résolution d'un hydrolysat d'hémoglobine bovine : applications." Compiègne, 1989. http://www.theses.fr/1989COMPDE84.

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Ce travail, présenté sous la forme de publications, concerne, l'étude de la production et de la résolution d'un hydrolysat enzymatique d'hémoglobine bovine. La première partie décrit la préparation en batch d'un hydrolysat pepsique décoloré en utilisant soit de l'alumine, soit de la magnésie. Ensuite une production en continu, au stade pilote, d'un hydrolysat pepsique incolore et reproductible a été mise au point. L'hydrolyse enzymatique de l'hémoglobine est réalisée dans un réacteur à ultrafiltration équipé de membranes minérales. La reproductibilité de l'hydrolysat ainsi produit a été démontrée. La seconde partie du travail concerne l'étude analytique de l'hydrolysat peptidique. Des méthodes chromatographiques associant dans un premier temps la basse pression et la HPLC, puis, utilisant la HPLC seule, ont été mises en œuvre pour résoudre ces hydrolysats complexes. Ces méthodes ont permis d'obtenir des peptides purs. La spectrométrie de masse (FAB) et l'analyse d'amino-acides ont été ensuite utilisées pour caractériser et identifier n'importe quel peptide ainsi purifié. Enfin, un exemple d'application de l'hydrolysat, dans le domaine de la réalisation de milieux de culture pour la recherche, a été présenté This work, presented in publications form, concerns the study of production and resolution of an enzymatic hydrolysate from bovine haemoglobin. The first part describes the batch preparation of a peptic decolorized hydrolysate using either alumina or magnesia. Then a continuous production, at the pilot-plant scale, of a reproductible and decolorized peptic hydrolysate was perfected. Enzymatic hydrolysis of haemoglobin was performed in an ultrafiltration reactor equipped with mineral membranes. The reproductibility of the hydrolysate was demonstrated. The second part of this work concerns the analytical study of the peptidic hydrolysate. Chromatographic methods, first associating low pressure and HPLC, and then using HPLC alone, were performed in order to resolve these complex hydrolysates. These methods allowed us to obtain pure peptides. Mass spectrometry (FAB) and amino acid analysis were then performed in order to characterise and identify any purified peptide. Finally, an application of the hydrolysate, in the area of culture media for research, was presented

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19

Rupprecht, Christian. "Ganzheitliche Verfahrens- und Schichtoptimierung für das Hochgeschwindigkeitsdrahtflammspritzen." Doctoral thesis, Universitätsbibliothek Chemnitz, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200900553.

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Das Ziel der Dissertation ist die Charakterisierung und Optimierung der Prozessbedingungen beim Hochgeschwindigkeitsdrahtflammspritzen. Dazu werden diagnostische Methoden wie das LDA-Verfahren, die Bewertung von Schichten und numerische Betrachtungen herangezogen. Verschiedene Spritzzusatzwerkstoffe wie Massiv- und Fülldrähte sowie hoch- und niedrigschmelzende Materialien werden verarbeitet. Zur Bewertung der Gebrauchseigenschaften erfolgen Korrosions- und Verschleißtests. Aus den Untersuchungsergebnissen resultieren Hinweise und Konzepte zur Verbesserung der Brennertechnik. Die Entwicklung eines neuen HVCW-Systems wird vorgestellt, welches Spritzpartikelgeschwindigkeiten im Überschallbereich ermöglicht, die deutlich über denen klassischer Systeme liegen. In einem gesonderten Abschnitt der Dissertation wird ein neuartiges Verfahren zur Herstellung hydrolysefähigen Materials vorgestellt. Der hergestellte Al-Sn-Werkstoff zersetzt sich in Kontakt mit Wasser unter Abgabe großer Mengen Wasserstoff in kürzester Zeit vollständig.

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20

Ticu, Elena-Loredana. "Proteoliza enzimatică dirijată a proteinelor alimentare în scopul obţinerii de peptide cu proprietăţi funcţionale sau biologice." Lille 1, 2006. https://ori-nuxeo.univ-lille1.fr/nuxeo/site/esupversions/b766d7b6-81c6-4172-8f51-d1111ae35818.

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La pepsine de porc est immobilisée sur un nouveau support minéral: l'alumine acide fonctionnalisée par la phosphoéthanolamine afin de diminuer l'adsorption des peptides produits au cours de l'hydrolyse de l'hémoglobine bovine. Ce support modifié avec la pepsine insolubilisée permet d'obtenir des cinétiques d'hydrolyse de l'hémoglobine proche de l'hydrolyse réalisée en catalyse homogène, où la pepsine est libre en solution, et de réduire l'adsorption des peptides. Le support modifié avec la pepsine immobilisée a était utilisé pour la mise au point d'un réacteur ouvert biphasique de type solide/liquide (CSTR), couplé ultérieurement à un extracteur biphasique liquide/liquide afin de réaliser l'extraction sélective des deux hémorphines, la LVVh-7 et la VVh- 7. Le solvant d'extraction est le butan-2-ol. Cela a permit d'obtenir un rendement d'extraction de 11 % pour la LVVh-7 et de 18% pour la VVh-7. Ensuite, afin d'optimiser l'extraction sélective de ces deux peptides par le solvant organique à partir d'hydrolysats d'hémoglobine, des recherches sont menées sur l'extraction sélective des deux hémorphines assistée par la formation de paires d'ions hydrophobes. De cette fois-ci, le solvant d'extraction est représenté par l'octan-1-ol et comme agent formateur de paires d'ions est utilisé le décanesulfonate. Les essais ont était réalisées à partir à la fois des solutions pures de peptides et d'un hydrolysat d'hémoglobine à différents rapport molaire: peptides / agent surfactant, et à tout les trois domaines de pH. Les résultats montre que la présence de l'agent formateur de paires d'ions était indispensable à l'extraction des ces deux peptides par le solvant et ainsi que le pH acide favorise leur extraction.

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Rupprecht, Christian. "Ganzheitliche Verfahrens- und Schichtoptimierung für das Hochgeschwindigkeitsdrahtflammspritzen." Eigenverlag, 2008. https://monarch.qucosa.de/id/qucosa%3A19103.

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Das Ziel der Dissertation ist die Charakterisierung und Optimierung der Prozessbedingungen beim Hochgeschwindigkeitsdrahtflammspritzen. Dazu werden diagnostische Methoden wie das LDA-Verfahren, die Bewertung von Schichten und numerische Betrachtungen herangezogen. Verschiedene Spritzzusatzwerkstoffe wie Massiv- und Fülldrähte sowie hoch- und niedrigschmelzende Materialien werden verarbeitet. Zur Bewertung der Gebrauchseigenschaften erfolgen Korrosions- und Verschleißtests. Aus den Untersuchungsergebnissen resultieren Hinweise und Konzepte zur Verbesserung der Brennertechnik. Die Entwicklung eines neuen HVCW-Systems wird vorgestellt, welches Spritzpartikelgeschwindigkeiten im Überschallbereich ermöglicht, die deutlich über denen klassischer Systeme liegen. In einem gesonderten Abschnitt der Dissertation wird ein neuartiges Verfahren zur Herstellung hydrolysefähigen Materials vorgestellt. Der hergestellte Al-Sn-Werkstoff zersetzt sich in Kontakt mit Wasser unter Abgabe großer Mengen Wasserstoff in kürzester Zeit vollständig.

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22

Tsai, Yi-Chen, and 蔡億澄. "Rapid Hydrolysis of Aluminum Nitride by Microwave." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/61054897742381890130.

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碩士 國立高雄應用科技大學 化學工程與材料工程系碩士在職專班 103 Aluminum nitride (AlN) can be easily hydrolyzed. However, the product layer increases the diffusion resistance, resulting to the decrease of hydrolysis rate. In this study, the microwave-assisted hydrolysis method was proposed for the rapid hydrolysis of AlN due to the energy transfer of microwave via the molecule polarization, leading to the reduction of the energy loss in the heat conduction process. Moreover, the effects of experimental parameters, including reaction temperature (25, 45, 70, 90 ℃), reaction time (0-129 min), and applied power (0, 50, 150 W) on the hydrolysis efficiency, were also discussed. The heating methods for AlN (2 μm) hydrolysis process were by flat heater, and microwave energy applied at 150 W or 50 W. The results showed that in the induction period (reaction time = 8 min), due to the rapid heating by microwave at 150 W, the conversion of AIN reached 73.0%, much higher than that by microwave at 50 W or flat heater (AlN conversion was about 18.2-20.1%). When the temperature was at 90℃ with the reaction time = 129 min, the conversion of AIN was consistency for three kinds of heating methods. By XRD patterns, the product of microwave-assisted AlN hydrolysis was mainly AlOOH (boehmite), and was very different with by flat heater (Al(OH)3). SEM photos also showed that the morphology of product was mainly composed by a large amount of lamellas boehmite AlOOH.

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Yu-ChiaChang and 張裕佳. "Stabilization of secondary aluminum dross via hydrolysis treatment." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/47490507663776696872.

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碩士 國立成功大學 資源工程學系 103 Domestic Aluminum Production Industry produces about over than ten thousand tons of secondary aluminum dross (the raw material), including Al2O3 and AIN. The secondary aluminum dross can easily react to the air and gives out unbearable stanch—improper management of the raw material will damage the overall environment. Considering different reaction time, processing temperature, reacting solvent, and solid to liquid ratio, the experiment of this study applies hydrolysis treatment to find out the best parameters. The result of this study shows, when NaOH is used as the solvent, thirty-minute reaction time, 60 Celsius degree of reaction temperature, and solid to liquid ratio as 1:100, the material’s efficiency of denitrification can reach a rather good 91.8%.

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Huang, Yen-Yu, and 黃硯毓. "Rapid Hydrolysis of Aluminum Nitride by Ultrasonic Wave-Enhanced Process." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/75845914021229082340.

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碩士 國立高雄應用科技大學 化學工程與材料工程系博碩士班 101 Due to the high reactivity of aluminum nitride (AlN) powder with water, the product layer will be generated on the surface of powders, resulting in the elevation of diffusion resistance and the difficulty of complete hydrolysis of AlN particles. Therefore, in this study, the rapid hydrolysis of aluminum nitride via the ultrasonic wave-enhanced process by means of the cavitation erosion of ultrasonic wave to decrease the diffusion resistance of product layer has been proposed. The performance of AlN hydrolysis is compared between the traditional heating process (THP) and ultrasonic wave-enhanced process (UWP). Moreover, the effects of initial reaction temperature (25℃, 50℃, 70℃), reaction time (10-1440 min), and initial pH values (pH0 = 3, 6.6, 12) on the performance of AlN hydrolysis has also been discussed The results showed that at 25℃, the conversion of AlN (2 μm) was only 87.2% after hydrolyzing 1440 min, and reached only 92.3% at 70℃ after 360 min of hydrolysis by using the THP. However, by using UWP, AlN was completed after 180 min of hydrolysis at 50℃. The trends for the increase of pH value and the measured NH4 + concentration in solution at 25℃ were consistent with the conversion of AlN for THP and UWP. According to the XRD patterns, a weak and broad peak of amorphous AlOOH was found at a short hydrolysis time, especially for THP, while apparent Al(OH)3 (bayerite) with a middle intensity of AlOOH (boehmite) crystallization phase at a longer reaction time or at a higher hydrolysis temperature had been identified. However, the SEM pictures showed that the morphology of the hydrolyzed-AlN powders was mainly composed by a large amount of lamellas boehmite with little of the columnar of bayerite,indicated that the bayerite crystallize phase was formed mainly in the internal of the AlN powders. Finally, the influences of various starting pH values (pH0) in solution by UWP on the conversion of AlN powder showed that the hydrolysis rate is in the orders: deionized water (pH0 = 6.6) ~ NaOH(aq) (pH0 = 12) > HCl(aq) (pH0 = 3).

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Jyun-SianLi and 李俊賢. "A study on the improvement of anti-hydrolysis property of aluminum nitride." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/42310750150465452359.

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Wang, Shan-Li, and 王尚禮. "Studies on the hydrolysis of aqueous solutions of aluminum perchlorate and formation of gibbsite." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/83728481192954616561.

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碩士 國立臺灣大學 農業化學系 81 The ferron-colorimetric kinetics method, sulfate precipitates, transmission and scanning electronic mocroscopies, x-ray diffraction, Al-27 solution and solid state nuclear magnetic resonance analysis were employed to study the speciations in aluminum hydrolytic solutions. The Al polycations or polymers present in these solutions were characterized. These polymeric species precipitated by sulfate anion were present in the shapes of sphere, lath and irregular morphologies. The tetrahedron coordinated Al structure in the lath-shape particles was identified by Al-27 solid state NMR. The Al hydrolytic solutions were synthesized and aged at 25 C and 70 C. Distribution of the Al polymeric species in these solutions were shown the variation at different temperatures. Samples synthesized under higher temperature had lower degree of hydrolysis and had a longer induction period on formation of gibbsite. For the duration of aging at room temperature, formation of gibbsite was caused by the decomposition of the polymeric Al species to monomeric Al or low OH-Al polymers and conversion to gibbsite.

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Dissertations / Theses on the topic 'Aluminum hydrolysis'

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