Cette étude se situe au carrefour d'une problématique opérationnelle de gestion des sols de bassins d'infiltration d'eaux pluviales et d'une thématique plus théorique sur le transport colloïdal. En effet, malgré la mise en évidence du rôle parfois prédominant des colloïdes dans le transport de polluants, les mécanismes considérés prennent encore peu en compte cette forme de transport et les conditions sous lesquelles il prédomine restent mal définies. Dans ce cadre, l'objectif principal de ces travaux est la caractérisation du transport colloïdal d'un métal caractéristique des pollutions d'eaux pluviales urbaines, le zinc. Les colloïdes considérés sont des bactéries de l'espèce Pseudomonas putida qui sont présentes dans le milieu poreux sous forme de biofilm. Les essais ont été réalisés en colonnes de sable de Loire, non saturées en eau. Des expériences complémentaires en réacteurs fermés ont permis de mieux caractériser la réactivité des surfaces mises en jeu. Les résultats permettent d'apporter des éléments de réponse à trois grandes questions qui sont en fait les conditions nécessaires pour qu'il y ait transport colloïdal : réactivité des colloïdes pour les polluants, mouvement des colloïdes, et transport associé. Tout d'abord, les titrations de surface et les essais d'adsorption ont montré la grande réactivité des surfaces en particulier du biofilm. Ensuite la composition de la solution en contact avec le milieux poreux et sa force ionique influencent largement la stabilité du biofilm et donc la formation de colloïdes mobiles. Ainsi les conditions sont réunies pour observer le transport associé du zinc et des bactéries; celui-ci n'a pas été directement quantifié, mais observé par des méthodes indirectes. Il apparaît donc nécessaire aujourd'hui de tenir compte, sous certaines conditions, du transport facilité par les colloïdes bactériens dans les sols de bassins d'infiltration.

Bidentate ligands are a commonly used class of ligands in catalysis that generate highly-active and selective catalysts. Such bidentate ligands, however, often suffer from synthetic challenges, which can be alleviated by the use of simpler monodentate ligands that assemble through non-covalent interactions to mimic the structure of bidentate ligands at the metal center. To produce a strongly assembled catalyst complex, the Hamilton receptor motif was utilized. Hamilton receptors form six hydrogen bonds with complementary guests and have binding affinities for barbiturates of up to 104 M-1 in CDCl3. Complete bifurcation of the Hamilton scaffold produces a modular ligand structure that allows for modification of either end of the supramolecular ligand structure. Similarly, the barbiturate guest can be synthetically altered creating both chiral guests and guests with differing amounts of steric bulk. Both experimental titration data and density functional theory calculations show that steric bulk discourages binding of the guest while a pre-organized host encourages guest inclusion. Electronic effects on the bifurcated Hamilton system were studied by varying the electron donating or withdrawing ability of the benzamide moiety on the host molecule. Electron withdrawing moieties produce more acidic amide hydrogens on the host which are able to participate in stronger hydrogen bonds with the guest resulting in a stronger host-guest complex. The effects of substitutions on the barbiturate guest were examined as well, and increased steric bulk on the guest resulted in decreased affinities with the host. The bifurcated Hamilton receptor ligands were examined in the palladium-catalyzed Heck reaction of iodobenzene with butyl acrylate. Pd2(OAc)4 was used as a control and all reaction yields with the diphenylphosphine ligand-stabilized Pd were greater than or equal to those obtained with Pd2(OAc)4 alone. The reaction rates did not correlate with the determined binding constants, suggesting that phosphine substitution on the guest plays a larger role than affinity of the complex for the guest. Reaction temperatures were varied, and at lower temperatures the yields increased implying that the strength of the hydrogen bonds between the metal complex and the guest does play a secondary role in the catalysis. This dissertation includes previously published co-authored material.

Research Doctorate - Doctor of Philosophy (PhD) / This work presents the development and application of modern data acquisition and analysis techniques for the investigations of equilibrium and kinetic reactions. The analytical technique is known as second order global analysis and a background of this relatively novel approach has been given. The theory behind and characteristics of the computer programs developed analysis as part of this research are described in Chapter Two along with descriptions of the instrumentation and programs developed for the acquisition of both potentiometric and spectrophotometric data. Applications of the developed programs include a potentiometric and spectrophotometric study of the protonation and stability equilibria of a series of polydentate N-donor ligands, as detailed in Chapter Three. The combination of potentiometric and spectrophotometric analysis has been shown to be a powerful analytical tool. Spectrophotometric titrations were also combined with fast stop-flow experiments in order to elucidate the complex reaction mechanisms associated with helicating ligands. The helication of the ligand ‘PepdaH₂’ with copper(II) and nickel(II) is examined in Chapter Four, along with discussions concerning the ability to induce chirality in the helicates from the addition of a chiral counter ion. Investigations into chirality were further continued in Chapter Five where the stereoselectivity of a benzimidazole-based ligand was investigated with circular dichroism titrations. The synthesis and characterisation of the benzimidazole-based ligands are provided, including a study of the ability of the ligands to form higher order complexes as investigated using electrospray mass spectroscopy. Chapter Six provides an in-depth discussion concerning the use of combined glass hydrogen selective electrodes for the determination of equilibrium constants, as this was a major focus of this research. Different calibration techniques are discussed and a description of the internal calibration technique developed is provided along with examples of the advantages of performing internal calibration of the electrode.

A despeito dos avanços instrumentais, as titulações continuam sendo largamente aplicadas em laboratórios de química analítica. Seu amplo uso está relacionado com a boa exatidão em aplicações bem estabelecidas e freqüente indicação como método de referência (p. ex., farmacopéias), equipamentos simples, comuns e de custo reduzido, consumo moderado de tempo e de reagentes. Entre as técnicas de titulação, destacam-se as potenciométricas (TP), empregadas universalmente para a quantificação de um ou mais componentes ácidos ou básicos em soluções aquosas ou não aquosas, possibilitando ainda determinar as constantes de dissociação de ácidos e de protonação de bases. Na análise de dados de TP são, via de regra, empregados os métodos clássicos (derivadas), porém, para sistemas compreendendo componentes multiprotonáveis, as inflexões das curvas de titulação deixam ser nítidas, especialmente em baixas concentrações. Nestas condições desfavoráveis, ainda assim podem-se obter resultados satisfatórios recorrendo a métodos de linearização das curvas ou analisando os dados por regressão não linear (RNL), facilmente implementáveis em computadores, hoje disseminados nos laboratórios. Outra técnica clássica para acompanhamento de titulações é a condutimétrica (TC), menos utilizada que a TP nos dias atuais, salvo para ácidos ou bases muito fracas, servindo para prover dados complementares em estudos de formação de complexos ou na caracterização de amostras ambientais. Tipicamente os pontos estequiométricos coincidem com a intersecção de segmentos de reta. Para amostras muito diluídas, com sistemas multipróticos ou com elevada concentração de eletrólitos em relação às espécies tituladas, a interpretação gráfica fica dificultada e a precisão decai. Pesquisas recentes mostraram que é possível aproveitar informações obtidas por TP para alimentar modelos de regressão não linear de TC e, assim, obter informações mais completas das amostras estudadas. No presente trabalho, avançou-se nesta linha criando programas computacionais para a análise simultânea de dados obtidos por TC e TP, empregando o método de RNL e minimizando os desvios (ou o quadrado dos desvios) dos dois conjuntos completos de dados para prover caracterização mais completa das amostras e melhoria na precisão dos resultados. Um programa de simulação de dados de TC e TP das mais diversas combinações e concentrações de sistemas ácido-base, com recursos para acrescentar erros aleatórios às variáveis simuladas, foi também desenvolvido. Permitiu verificar a validade e potencialidade do método da TPC-RNL e aperfeiçoar o programa de análise simultânea de dados. O programa de TPC-RNL foi aplicado inicialmente à re-avaliação de dados de titulações de água de chuva anteriormente coletadas e analisadas por outro colaborador do grupo. Como exemplo de aplicação original a amostras reais difíceis tanto para a TC como a TP isoladamente, determinou-se, por TPC, baixas concentrações de ácidos orgânicos de baixo peso molecular em amostras obtidas do produto de oxidação acelerada do biodiesel. Os resultados se mostraram compatíveis com os obtidos por outro pesquisador que recorreu à eletroforese capilar, sendo que o pH, a condutividade e a força iônica das amostras também foi reproduzida pelo programa Peak Master alimentado com as concentrações ajustadas por RNL / Despite all the advances in instrumental techniques, titrations are still widely applied in analytical chemistry laboratories. Its widespread use is associated with good accuracy, well established applications, simple, readily available and low cost equipment, moderate consumption of time and reagents and frequent indication as a reference method (eg., Pharmacopoeias). Potentiometric titrations (PT) outstands among other techniques, being universally used for the quantification of one or more basic or acidic components in aqueous or non aqueous samples and enabling further determination of the dissociation constants of acids and bases. Data analysis of PT with the glass electrode is typically done by finding the inflections of the curves with help of simple derivatives. However, PT curves of systems with multiprotonable components, specially at very low concentrations, fail to show sharp inflections. Under such unfavorable conditions, satisfactory results can still be obtained by using curve linearization methods or nonlinear regression (NLR) methods, now at the reach of every laboratory computer. Another classic technique for following titrations is conductivity (CT), less used routinely than PT nowadays except for very weak acids or bases, but still valuable as a complementary technique in equilibrium studies of complex formation or for the characterization of environmental samples. The stoichiometric points of simple CTs are found at the intersection of line segments. For very dilute samples or for multiprotic systems or with high concentrations of electrolytes compared to the species to be titrated, the graphical interpretation becomes difficult and the accuracy declines. Recent research has shown that it is possible to harness information obtained by PT to render non-linear regression models of CT solvable, thus extracting more complete information of the samples. This dissertation is devoted to the development and evaluation of software for the simultaneous analysis of data from CT and PT gathered together in the laboratory or by simulation, using the method of NLR with minimization of the weighted deviations (or their squares) of the two full data sets to provide more complete characterization of the samples and to improve the precision of the results. A simulation program for generating CT and PT curves for freely combined acid-base systems over a wide concentration range, with features to add random errors to the simulated variables was also developed. The simulator was used to evaluate the validity and potentiality of the PCTNLR method and improve the software of simultaneous data analysis. The program of PCT-NLR was applied firstly to the re-evaluation of data from titrations of rainwater collected and analyzed previously by another contributor to the group. As an original application example to real samples that are difficult for CT or PT separately, low concentrations of organic acids of low molecular weight were determined by PCT-NLR in samples from accelerated biodiesel oxidation tests. The results were consistent with those obtained by another researcher who used the capillary electrophoresis. The pH, ionic strength and conductivity of the samples were also reproduced by the program Peak Master using concentrations adjusted by NLR

A despeito dos avanços instrumentais, as titulações continuam sendo largamente aplicadas em laboratórios de química analítica. Seu amplo uso está relacionado com a boa exatidão em aplicações bem estabelecidas e freqüente indicação como método de referência (p. ex., farmacopéias), equipamentos simples, comuns e de custo reduzido, consumo moderado de tempo e de reagentes. Entre as técnicas de titulação, destacam-se as potenciométricas (TP), empregadas universalmente para a quantificação de um ou mais componentes ácidos ou básicos em soluções aquosas ou não aquosas, possibilitando ainda determinar as constantes de dissociação de ácidos e de protonação de bases. Na análise de dados de TP são, via de regra, empregados os métodos clássicos (derivadas), porém, para sistemas compreendendo componentes multiprotonáveis, as inflexões das curvas de titulação deixam ser nítidas, especialmente em baixas concentrações. Nestas condições desfavoráveis, ainda assim podem-se obter resultados satisfatórios recorrendo a métodos de linearização das curvas ou analisando os dados por regressão não linear (RNL), facilmente implementáveis em computadores, hoje disseminados nos laboratórios. Outra técnica clássica para acompanhamento de titulações é a condutimétrica (TC), menos utilizada que a TP nos dias atuais, salvo para ácidos ou bases muito fracas, servindo para prover dados complementares em estudos de formação de complexos ou na caracterização de amostras ambientais. Tipicamente os pontos estequiométricos coincidem com a intersecção de segmentos de reta. Para amostras muito diluídas, com sistemas multipróticos ou com elevada concentração de eletrólitos em relação às espécies tituladas, a interpretação gráfica fica dificultada e a precisão decai. Pesquisas recentes mostraram que é possível aproveitar informações obtidas por TP para alimentar modelos de regressão não linear de TC e, assim, obter informações mais completas das amostras estudadas. No presente trabalho, avançou-se nesta linha criando programas computacionais para a análise simultânea de dados obtidos por TC e TP, empregando o método de RNL e minimizando os desvios (ou o quadrado dos desvios) dos dois conjuntos completos de dados para prover caracterização mais completa das amostras e melhoria na precisão dos resultados. Um programa de simulação de dados de TC e TP das mais diversas combinações e concentrações de sistemas ácido-base, com recursos para acrescentar erros aleatórios às variáveis simuladas, foi também desenvolvido. Permitiu verificar a validade e potencialidade do método da TPC-RNL e aperfeiçoar o programa de análise simultânea de dados. O programa de TPC-RNL foi aplicado inicialmente à re-avaliação de dados de titulações de água de chuva anteriormente coletadas e analisadas por outro colaborador do grupo. Como exemplo de aplicação original a amostras reais difíceis tanto para a TC como a TP isoladamente, determinou-se, por TPC, baixas concentrações de ácidos orgânicos de baixo peso molecular em amostras obtidas do produto de oxidação acelerada do biodiesel. Os resultados se mostraram compatíveis com os obtidos por outro pesquisador que recorreu à eletroforese capilar, sendo que o pH, a condutividade e a força iônica das amostras também foi reproduzida pelo programa Peak Master alimentado com as concentrações ajustadas por RNL / Despite all the advances in instrumental techniques, titrations are still widely applied in analytical chemistry laboratories. Its widespread use is associated with good accuracy, well established applications, simple, readily available and low cost equipment, moderate consumption of time and reagents and frequent indication as a reference method (eg., Pharmacopoeias). Potentiometric titrations (PT) outstands among other techniques, being universally used for the quantification of one or more basic or acidic components in aqueous or non aqueous samples and enabling further determination of the dissociation constants of acids and bases. Data analysis of PT with the glass electrode is typically done by finding the inflections of the curves with help of simple derivatives. However, PT curves of systems with multiprotonable components, specially at very low concentrations, fail to show sharp inflections. Under such unfavorable conditions, satisfactory results can still be obtained by using curve linearization methods or nonlinear regression (NLR) methods, now at the reach of every laboratory computer. Another classic technique for following titrations is conductivity (CT), less used routinely than PT nowadays except for very weak acids or bases, but still valuable as a complementary technique in equilibrium studies of complex formation or for the characterization of environmental samples. The stoichiometric points of simple CTs are found at the intersection of line segments. For very dilute samples or for multiprotic systems or with high concentrations of electrolytes compared to the species to be titrated, the graphical interpretation becomes difficult and the accuracy declines. Recent research has shown that it is possible to harness information obtained by PT to render non-linear regression models of CT solvable, thus extracting more complete information of the samples. This dissertation is devoted to the development and evaluation of software for the simultaneous analysis of data from CT and PT gathered together in the laboratory or by simulation, using the method of NLR with minimization of the weighted deviations (or their squares) of the two full data sets to provide more complete characterization of the samples and to improve the precision of the results. A simulation program for generating CT and PT curves for freely combined acid-base systems over a wide concentration range, with features to add random errors to the simulated variables was also developed. The simulator was used to evaluate the validity and potentiality of the PCTNLR method and improve the software of simultaneous data analysis. The program of PCT-NLR was applied firstly to the re-evaluation of data from titrations of rainwater collected and analyzed previously by another contributor to the group. As an original application example to real samples that are difficult for CT or PT separately, low concentrations of organic acids of low molecular weight were determined by PCT-NLR in samples from accelerated biodiesel oxidation tests. The results were consistent with those obtained by another researcher who used the capillary electrophoresis. The pH, ionic strength and conductivity of the samples were also reproduced by the program Peak Master using concentrations adjusted by NLR

Convergent and divergent strategies for the synthesis of viologen dendrimers with 1,3,5-tri-methylene branching units are presented. The synthesis of 3,5-bis(hydroxymethyl) benzyl bromide was optimized. The analysis of the crystal structure of 1-[3,5-bis(hydroxymethyl)benzyl]-4-(pyridin-4-yl) pyridinium hexafluorophosphate together with PM3 calculations opens an avenue to judge the structure and conformation of benzylic viologen dendrimers. In order to study chemical trigger induced conformational changes, viologen dendrimers were spin-labeled via a divergent approach. 1-(2,4-dinitrophenyl)-4-(pyridin-4-yl)pyridinium hexafluorophosphate was used as the end group to yield an activated dendrimer of the respective generation. The corresponding dendrimers were spin-labeled by reacting the active functionality with 4-amino TEMPO. The products were characterized by ESR (spin-label efficiency) and conventional cyclic voltammetry. Dynamic ESR studies are planned. New trimethylene-dipyridinium dendrimers were synthesized via a divergent approach using 4-tert-butylbenzyl group as the peripheral group. These dendrimers are well soluble in DMF or DMSO as PF6 salts and they act as a host for anthraquinone-2,6-disulfonate (AQDS). They can be stoichiometrically titrated with AQDS as shown by 1H-NMR, DOSY and cyclic voltammetry. Upon loading them with AQDS, the dendrimers undergo first a contraction, they reach a minimum hydrodynamic radius for complete charge compensation and they re-open when overcharging takes place. The contraction is supported by MM+ calculations. Upon stepwise loading of G2 (42 positive charges) with AQDS (2 negative charges), the first 3 molar equivalents (6 neg. charges) occupy the innermost dendrimer shell (consisting of 6 pos. charges), the next 6 equivalents (12 neg. charges) occupy the middle shell (12 pos. charges) and the last 12 equivalents AQDS (24 neg. charges) occupy the outermost shell of the dendrimer (24 pos. charges), as supported by 1H-NMR titrations yielding the magic equivalent numbers of 3, 9=3+6, and 21=3+6+12. Such stepwise radial complexations again in DMSO were further demonstrated using other molecular guests (mono-, di- and trianionic) as well as with on purpose synthesized viologen dendrimers. α,ω-dibromoalkanes were bifunctionalized in two steps to yield alkyl phosphonates with pyridinium, trimethylenedipyridinium, bipyridinium or a sulfonate at their ω end. These compounds were used as surface modifiers to build biomimetic membranes on the pore walls of mesoporous TiO2. Host-guest interaction studies with on purpose synthesized viologen compounds have been performed in collaboration.

Yes / The association constants for formation of 1 : 1 complexes between a H-bond donor, 1-naphthol, and a diverse range of charged and neutral H-bond acceptors have been measured using UV/vis absorption and fluorescence emission titrations. The performance of 1-naphthol as a dual colorimetric and fluorescent molecular recognition probe for determining the H-bond acceptor (HBA) parameters of charged and neutral solutes has been investigated in three solvents. The data were employed to establish self-consistent H-bond acceptor parameters (β) for benzoate, azide, chloride, thiocyanate anions, a series of phosphine oxides, phosphate ester, sulfoxide and a tertiary amide. The results demonstrate both the transferability of H-bond parameters between different solvents and the utility of the naphthol-based dual molecular recognition probe to exploit orthogonal spectroscopic techniques to determine the HBA properties of neutral and charged solutes. The benzoate anion is the strongest HBA studied with a β parameter of 15.4, and the neutral tertiary amide is the weakest H-bond acceptor investigated with a β parameter of 8.5. The H-bond acceptor strength of the azide anion is higher than that of chloride (12.8 and 12.2 respectively), and the thiocyanate anion has a β value of 10.8 and thus is a significantly weaker H-bond acceptor than both the azide and chloride anions. / Supported by the ESPRC.

Acid/base and metal ion adsorption properties have been investigated for a range of chemically modified bleached Kraft fibre materials (pulps). The studies were performed via potentiometric titrations, Flame Atomic Absorbtion (and Emission) Spectroscopy, Inductively Coupled Plasma Optical Emission Spectroscopy and Extended X-ray Absorbtion Fine Structure measurements. As a result of a chemical modification procedure, the total concentration of acidic carboxylate groups in the fibre materials ranged between 43 and 590 μmol/g. The preferable surface potential model for modelling the ionic strength dependent acid/base properties of fibre materials with low charge densities, i.e. unmodified fully bleached Kraft fibre materials, was found to be the Basic Stern Model. For fibre materials with high total charge, ≳100 μmol/g, this model resulted in poor fits to data, and for such materials a number of Constant Capacitance Models, one at each ionic strength, must be recommended. With respect to metal ion adsorption, the results have indicated that the unspecific Donnan theory could correctly model the simultaneous adsorption of several metal ions, i.e. K+, Na+, Mg2+, Ca2+ and Cu2+, provided that the salt concentration in the fibre suspension is low. In suspensions of high salt concentration it was, however, found that this very same model strongly underestimated the adsorption of Ca2+ and Cu2+. Here, the Donnan model had to be complemented by specific ion exchange equilibria. These results were corroborated by spectroscopic evidence of specific interactions between Cu2+-ions and fibres. The spectroscopic indication of a complex formed between two fibre surface carboxylate groups and one Cu2+-ion, agree with the specific ion exchange model. It was therefore concluded that specific metal ionfibre interactions cannot be neglected, especially at high salt concentrations. The interactions occurring between the polycation GaO4Al12(OH)24(H2O)127+ and fibre materials were studied by both adsorption and spectroscopic measurements. These indicate that GaO4Al12(OH)24(H2O)127+ is surprisingly stable in fibre suspensions and that intact GaO4Al12(OH)24(H2O)127+- ions are strongly adsorbed onto the fibres. Also for this ion, specific interactions has to be considered, since the strong adsorption registered was too strong to be explained by Donnan equilibria. In the thesis, the stochiometric composition and an equilibrium constant characterising these interactions is presented.

The Suwannee River natural organic matter (SRNOM) was fractionated by preparative size-exclusion chromatography (SEC) into seven molecular weight (MW) fractions. The SRNOM and its MW fractions were subsequently analyzed for their concentrations of acidic functional groups by direct titrations, average MWs and MW distributions by semi-analytical SEC, and charge-to-MW distributions by capillary electrophoresis. Carboxyl concentrations in the MW fractions were inversely proportional to their average MWs. Conversely, the phenolic concentrations, though smaller than the carboxyl concentrations, were proportional to average MWs. Hysteresisthe non-overlap between sequential forward and reverse titrationswas observed for the SRNOM and its MW fractions, where the reverse titrations predicted a greater concentration of carboxylic acid groups than the forward titration. Because hysteresis is thought to be caused by the base-catalyzed hydrolysis of esters, this suggests that ester groups in the SRNOM are distributed over all MWs. Data for direct titrations, MW distributions, and capillary electrophoresis were evaluated by a computational scheme that solves for the most probable distribution of acidic functional groups and charges on solutes in the SRNOM and the MW fractions as a function of pH. Depending on the MW ranges of the samples, solutes in the SRNOM and the MW fractions are predicted to have from one to a maximum of 25 carboxyl groups per solute. Most phenolic groups are predicted to be on solutes that have a minimum of two carboxyl groups. At low pH, all samples have high relative abundances of solutes with the lowest charges. The charges of solutes are predicted to increase with increasing pH due to the sequential ionization of acidic functional groups. Depending on the MW ranges of the samples, the maximum probable charges of solutes in the SRNOM and the fractions at high pH are -12 to -30. By knowing the most probable distribution of charge and abundances of acidic functional groups, researchers will make better estimates of thermodynamic parameters and models that describe equilibria between metals and natural organic matter in the environment.

The thesis is a summary and discussion of eight papers. During the last decades, precipitation has become increasingly acidic due to the extensive use of fossil fuels. In areas of poorly buffered bedrocks, e.g. Scandinavia, northeastern United States, this phenomenon has resulted in elevated amounts of Al(III) being leached into streams and lakes. Recent findings reveal that these elevated Al-concentrations could cause fish death and decreasing forest production. In the present thesis, the importance of taking naturally occurring substances into consideration when discussing Al(III) in natural waters, is emphasized. On the basis of a chemical characterization of relevant ligand classes in a natural water, the complex formation between Al^+, hydroxide ions and the inorganic ligand carbonic acid, the low-molecular weight organic ligand citric acid and the high-molecular weight model substances gallic acid, 1,2-dihydroxynaphtha-lene-4-sulfonate, 1,2-naphthoquinone-4-sulfonate, pyrocatechol and salicylic acid were investigated. The investigations were performed as series of Potentiometrie titrations and data were processed by means of the least-squares computer program LETAGROPVRID using a technique called pqr-analysis, permitting an unbiased search for complex model (and corresponding equilibrium constants) to be made. In most systems studied, the complexation at high ligand excesses can be described by a series of mononuclear complexes AIL-AIL^. Tentatively, the whole series consists of octahedrally coordinated (water and ligand oxygens) AI(III). At lower ligand excesses, the significance and in some cases even predominance of ternary mono- and polynuclear hydroxo complexes is demonstrated. In two of the systems, binary aluminium hydroxo species are evaluated. The potential importance of the substances with respect to Al-com-plexation in natural waters are indicated in a number of model calculations. The solubility of the clay mineral kaolinite is calculated as a function of -lg[H+] and ligand concentration. It is shown that citric acid, gallic acid, 1,2-dihydroxynaphthalene-4-sulfonate, pyrocatechol and salicylic acid contribute quite significant to the total solubilities, even at very low concentrations. As a complement and background to the equilibrium studies, the corrosion rate for one of the naturally occurring Al-bearing minerals, corundum, is reported. In this investigation, performed with a leach-ant solution of ground-water composition, an experimental technique was employed which made it possible to divide the corrosion into chemical and mechanical losses. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1983</p> / digitalisering@umu