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Chromo kompleksinių dažiklių sorbcija jonitais ir aktyvintosiomis anglimis / Sorption of chromium complex dyes onto ion exchangers and activated carbonsKirkutė, Jolita 24 September 2008 (has links)
Chromo kompleksinių dažiklių: rūgštinio rudojo (1:1 ir 1:2 chromo kompleksai) ir rūgštinio mėlynojo (1:2 chromo kompleksas) sorbcija aktyvintąja anglimi, neutraliu sorbentu, anijonitu bei chelatiniu jonitu atlikta statinėmis sąlygomis, keičiant pradinio tirpalo koncentracijas, pH, temperatūrą bei sorbcijos trukmę. Pusiausvirosios sorbcijos eksperimentinės vertės ir apskaičiuoti Langmiuro ir Froindlicho teorinių sorbcijos izotermų paramertrų didžiausios vertės liudija, kad sorbcijai palankiausia tirpalo rūgšti terpė. Gautos sorbcijos kinetinės kreivės ir ištirtos pagal tris kinetikos modelius: pseudo-pirmojo laipsnio reakcijos greičio lygtį, pseudo-antrojo laipsnio reakcijos greičio lygtį ir vidinės difuzijos modelį. Nustatyta, kad sorbcijos kinetika vyksta pagal pseudo-antrojo laipsnio reakcijos lygtį ir yra kontroliuojama vidinės difuzijos procesų. Nustatyti sorbcijos proceso termodinaminiai parametrai H0, S0 ir G0 liudija apie spontanišką, egzoterminę sorbcijos aktyvintąja anglimi, anijonitu bei chelatiniu jonitu prigimtį. / Sorption of two chromium complex dyes (1:1 and 1:2 chromium complex; 1:2 chromium comlex) and from model solutions onto an various types of sorbents was investigated in aqueous solution in a batch experiments with respect to initial solution concentration and pH, contact time, and temperature. The sorption capacity at equilibrium obtained experimental and estimated Langmuir and Freundlich isotherm parameters was demonstrate that acidic media was favourable for dye sorption. The pseudo-first-order, pseudo - second order kinetics models and the diffusion (intraparticle) model were used to describe the kinetics data, and the rate constants were evaluated. Kinetics of dye sorption is observed to confirm pseudo-second order rate expression. The activation energy, change of Gibbs free energy, enthalpy of sorption was also evaluated. The results indicate the sorption process onto activated carbon, anion exchanger and chelating sorbent was egzothermic, spontaneous.
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Selective Separation Of Wood Components In Internal Process Waters Originating From Mechanical PulpingZasadowski, Dariusz January 2014 (has links)
Dissolved and Colloidal substances (DSC) and metals are released from woodduring thermomechanical pulp (TMP) production. These components have atendency to accumulate in process waters, as the water circulation systems inintegrated paper mills are closed. Disturbances such as pitch depositions in thepaper machine (pitch problems), specks in the paper, decreased wet and drystrength, interference with cationic process chemicals, and impaired sheetbrightness and friction properties appear when DSC are present. Transition metalions such as manganese results in higher consumption of bleaching chemicals(hydrogen peroxide) and lowers the optical quality of the final product, andaddition of complexing agents, such as EDTA or DTPA, to prevent this is needed.The never ending trends to decrease water consumption and increase processefficiency in pulp and paper production emphasizes that it is very important bothto know the effects of wood substances on pulping and papermaking and to beable to remove them in an efficient way. From a biorefinery point of view, DSCcomponents can be promising renewable raw materials for biofuels, bio‐basedchemicals and materials.In this thesis, a new approach using induced air flotation (IAF) without a cationicpolyelectrolyte addition for the removal of pitch and metal ions from mechanicalpulp mill process waters is presented. The induced air flotation of different processwaters is facilitated by the addition of a chelating surfactant and different foamingagents. The influence of the pH value, temperature and foaming agentconcentration on the flotation efficiency has been investigated. The investigations presented show that the disturbing components can be removed from TMP presswater to a high extent. A 90% decrease in turbidity and a 91% removal of lipophilicextractives (i.e. resin and fatty acids, triglycerides, sterols and steryl esters) fromunbleached and bleached TMP process water can be obtained by addition of acationic surfactant as foaming agent during flotation. Lower amount of foamingagent is needed to purify efficiently bleached TMP process water, than unbleached.Additionally, fibres located in TMP press water are not removed with the foamfraction but purified. A retained concentration of hydrophilic extractives (i.e.hemicelluloses and lignans) in the process water indicates that the flotation isselective. Moreover, by introduction of a new recoverable surface activecomplexing agent, a chelating surfactant, manganese ions in the form of chelatescan be successfully removed from the pulp fibres and separated from the processwater in the same flotation process. Furthermore, from the purified unbleachedTMP process water a 90% recovery of dissolved hemicelluloses by anti‐solventprecipitation was obtained.The findings presented above indicate new possibilities for the internal watercleaning stage to decrease DSC emissions to recipient and for recovery of valuableraw materials from purified process water if flotation technology is applied in anintegrated mechanical pulp mill. / FORE
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Fundamental Characterization and Technical Aspects of a Chelating SurfactantSvanedal, Ida January 2014 (has links)
The purpose of this study was to investigate the fundamental characteristics of a chelating surfactant in terms of solution behaviour, chelation of divalent metal ions, and interaction in mixtures with different foaming agents and divalent metal ion, as well as examining its prospects in some practical applications. Chelating surfactants are functional molecules, with both surface active and chelating properties, which are water soluble and therefore suitable for chelation in many aqueous environments. The dual functionality offers the possibility to recover the chelating surfactant as well as the metals. The DTPA (diethylenetriaminepentaacetic acid)-based chelating surfactant 4-C12-DTPA (2-dodecyldiethylenetriaminepentaacetic acid) was synthesized at Mid Sweden University. In the absence of metal ions, all eight donor atoms in the headgroup of 4-C12-DTPA are titrating and the headgroup charge can be tuned from +3 to -5 by altering the pH. The solution properties, studied by surface tension measurements and NMR diffusometry, were consequently found strongly pH dependent. pH measurements of chelating surfactant solutions as a function of concentration was used to extract information regarding the interaction between surfactants in the aggregation process. Small differences in the conditional stability constants (log K) between coordination complexes of DTPA and 4-C12-DTPA, determined by competition measurements utilizing electrospray ionization mass spectrometry (ESI-MS), indicated that the hydrocarbon tail only affected the chelating ability of the headgroup to a limited extent. This was further confirmed in hydrogen peroxide bleaching of thermomechanical pulp (TMP) treated with 4-C12-DTPA. Interaction parameters for mixed systems of 4-C12-DTPA and different foaming agents were calculated following the approach of Rubingh’s regular solution theory. The mixtures were also examined with addition of divalent metal ions in equimolar ratio to the chelating surfactant. Strong correlation was found between the interaction parameter and the phase transfer efficiency of Ni2+ ions during flotations. Furthermore, a significant difference in log K between different metal complexes with 4-C12-DTPA enabled selective recovery of the metal ion with the highest log K. The findings in this study contribute to the understanding of the fundamental characteristics of chelating surfactants, which can be further utilized in practical applications.
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Efeito do cádmio sobre a enzima d-aminolevulinato desidratase de pulmão de ratos in vitro: interação com agentes quelantes e antioxidantes / Effects of cadmium on d-aminolevulinate dehydratase from rat lung in vitro: interaction with chelating and antioxidant agentsLuchese, Cristiane 01 June 2007 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The exposure of human populations to a variety of heavy metals has been a public health concern. Cadmium is a non-essential elements due to its immense usage in various industrial applications, is an environmental contaminant with food and tobacco smoking. This toxic metal is more efficiently absorbed through the lungs than through the gastrointestinal tract. Therefore, the use of lung as a target tissue of cadmium exposure is of great importance because this heavy metal can be absorbed on suspended particles, entering the lung through the respiration. Thus, a possible therapy for metal intoxication is to remove the toxic metals from the bound functional bioligands. The present study was designed to evaluate the effect of cadmium on d-minolevulinate dehydratase (d-ALA-D) activity from rat lung in vitro. d-ALA-D activity, a toxicological parameter, has been reported as a target of cadmium in different tissues. The protective effect of monotherapies with dithiol chelating (meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercaptopropane-1- sulfonic acid (DMPS)) or antioxidant agent (ascorbic acid, diphenyl diselenide, (PhSe)2, and Nacetylcysteine (NAC)) were also evaluated; as well as, the effect of a combined therapy (dithiol chelating x antioxidant agent) was studied. Moreover, to investigate the possible mechanism involved, we determined the effect of zinc chloride (ZnCl2) and dithiothreitol (DTT). The rat lung d-ALA-D activity was inhibited by low concentrations of cadmium, this inhibition occurred due the oxidation of SH groups of enzyme, and not by displacing zinc from the enzyme structure. The chelating agents were not effective in restoring enzyme activity inhibited by cadmium, and it presented an inhibitory effect per se. The possible mechanism involved in this inhibition was demonstrated. DTT restored the inhibition caused by both chelating agents, but ZnCl2 restored only the inhibitory effect of DMSA. This indicated that DMPS did not remove the zinc ions of the enzyme structure. This study also demonstrated that these chelating agents potentialized the d-ALA-D inhibition caused by cadmium. In this way, the study of possible mechanism verified that DTT restore the enzyme inhibition caused by cadmium/DMSA complex, but not by cadmium/DMPS complex. In contrast to DTT, ZnCl2 did not restore the enzyme activity inhibited by both complexes. In relation to antioxidants compounds, we can verify that none antioxidant utilized in this work was efficient in restoring the enzyme activity inhibited by cadmium. Some authors had demonstrated that the association of chelating and antioxidant agents is a good alternative in treatment of metal intoxication. In this way, we observed a combined effect of cadmium x DMPS x (PhSe)2 and cadmium x DMPS x NAC. However, this combined effect of cadmium x antioxidant x chelating did not observe when we utilized DMSA as chelating agent. In general, the results of this study indicate that cadmium inhibited the pulmonary d-ALA-D activity; and, the use oh chelating and antioxidant agents, alone or combined, 6 did not restore the enzyme activity, in some cases, potentialized the inhibition induced by cadmium. The principal mechanism involved in enzyme inhibition was the oxidation of SH groups. / A exposição das populações humanas a uma variedade de metais pesados é um problema de saúde pública. O cádmio é um elemento não essencial e devido ao seu imenso uso em diversas aplicações industriais, é um contaminante ambiental
através da comida e da fumaça do cigarro. Este metal tóxico é mais eficientemente absorvido através dos pulmões do que do trato gastrointestinal. Portanto, o uso dos pulmões como um tecido alvo do cádmio é de grande importância porque este metal pesado pode ser absorvido, entrando nos pulmões através da respiração. Uma terapia possível para a intoxicação por metais é remover os metais tóxicos ligados a
bioligantes funcionais. O presente estudo foi delineado para avaliar o efeito in vitro do cádmio na atividade da d-aminolevulinato desidratase (d-ALA-D) em pulmão de
rato. A atividade da d-ALA-D, um parâmetro toxicológico, tem sido reportada como alvo do cádmio em diferentes tecidos. Foram avaliados também o possível efeito protetor dos agentes quelantes ditiólicos (ácido 2,3-dimercapto-1-propanosulfônico (DMPS) e o ácido meso 2,3- dimercaptosuccínico (DMSA)) ou agentes antioxidantes
(ácido ascórbico, N-acetilcisteína (NAC) e o disseleneto de difenila (PhSe)2) isolados ou em combinação (agentes quelantes x antioxidantes). Além disso, para investigar
o possível mecanismo envolvido, nós determinamos o efeito restaurador do cloreto de zinco (ZnCl2) e do ditiotreitol (DTT) na d-ALA-D. A atividade da d-ALA-D de pulmão de rato foi inibida por baixas concentrações de cádmio, e esta inibição
ocorreu devido a oxidação dos grupos -SH da enzima, e não por remover os íons zinco da estrutura enzimática. Os agentes quelantes não foram efetivos em proteger a atividade da enzima inibida por cádmio, e apresentaram um efeito inibitório per se. O possível mecanismo envolvido nesta inibição foi demonstrado. O DTT restaurou a inibição causada por ambos agentes quelantes, mas o ZnCl2 restaurou somente o efeito inibitório do DMSA. Isto indica que o DMPS não remove os íons zinco da estrutura da enzima. Este estudo demonstrou também que estes agentes quelantes potencializam a inibição da d-ALA-D causada por cádmio. Neste sentido, o estudo do possível mecanismo verificou que o DTT restaura a inibição da enzima causada pelo complexo cádmio/DMSA, mas não pelo complexo cádmio/DMPS. Ao contrário do DTT, o ZnCl2 não restaura a atividade da enzima inibida por ambos complexos. Em relação aos compostos antioxidantes, nós podemos verificar que nenhum antioxidante utilizado neste trabalho foi eficiente em restaurar a atividade da enzima inibida por cádmio. Alguns autores têm demonstrado que a associação de agentes quelantes e antioxidantes é uma boa alternativa no tratamento das intoxicações por metais. Neste sentido, observou-se um efeito combinado de cádmio x DMPS x (PhSe)2 e cádmio x DMPS x NAC. Porém esse efeito combinado de cádmio x
antioxidantes x quelantes não foi observado quando se utilizou o DMSA como 4 agente quelante. De uma maneira geral, os resultados deste estudo indicam que o cádmio inibiu a atividade da d-ALA-D do tecido pulmonar; e ainda, o uso de agentes quelantes e antioxidantes, sozinhos ou combinados, não restauraram a atividade da enzima, sendo que em alguns casos, potencializaram a inibição induzida por cádmio. O mecanismo principal envolvido na inibição da enzima foi à oxidação dos grupos sulfidrílicos.
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Cuprúria em pais de pacientes com doença de Wilson antes e depois da administração oral de d-penicilamina / Cupriuresis in parents of patients with Wilson disease before and after oral intake of d-penicillamineJakeliny Vieira 31 May 2007 (has links)
A doença de Wilson (DW) é distúrbio da excreção biliar de cobre, de herança autossômica recessiva, devido a mutações no gene ATP7B. O cobre que não se liga à apoceruloplasmina circula no organismo ligado a aminoácidos, deposita-se principalmente no fígado e no cérebro e é excretado pelos rins. A cuprúria maior que 100ug/24h pode auxiliar no diagnóstico, embora cerca 20% dos pacientes com DW apresentem níveis anormais de cuprúria basal. A administração da d-penicilamina (DPA) pode promover, em crianças, valores maiores que 1.600ug/24h. A fim de se conhecer os níveis de cuprúria de possíveis indivíduos heterozigotos adultos, foram avaliados 25 pais e 25 mães de pacientes (média 61 anos em homens; 57 anos em mulheres) com diagnóstico de DW. Foram obtidos os níveis séricos de enzimas hepáticas, cobre e ceruloplasmina, e quantificada a cuprúria de 24h. A seguir, os indivíduos receberam DPA 1,0g por via oral dividido em duas tomadas, durante nova coleta de urina para dosagem de cuprúria de 24h. Esta análise foi realizada pelo método de espectrometria de absorção atômica eletrotérmica. Os níveis de enzimas hepáticas foram semelhantes nos dois grupos, exceto o nível médio de fosfatase alcalina que foi maior nas mulheres (H= 68,72 UI/L; M=81,68 UI/L). Os níveis de ceruloplasmina (H=21,72mg/dL; M=27,78mg/dL) e de cobre sérico (H=71,38 ?g/dl; M=88,0 ug/dl) foram maiores em mulheres do que em homens (p<0,001). Os níveis de cuprúria basal foram 22,43ug/24h (média) e 21,40ug/24h (mediana); e, após a DPA, de 523,54 ug/24h (média) e 511,5 ug/24h (mediana). A cuprúria média basal masculina foi de 26,19. ug/24h, enquanto a feminina foi de 18,28. ug/24h (p=0,005). Com o presente estudo, ficou definida possível faixa de variação da cuprúria antes e depois da administração de dpenicilamina em pais de portadores com doença de Wilson; que os pais apresentaram cupremia e níveis de ceruloplasmina menores e cuprúria basal maior do que as mães; que as faixas de variação de normalidade para os parâmetros ceruloplasmina, cobre sérico e urinário deveriam ser diferenciadas de acordo com o sexo. / Wilson disease is a biliary copper excretion disturbance, of recessive autossomic heritage, due to ATP7B gene mutations. The copper not bound to apoceruloplasmin circulates in the organism bound to amino acids and accumulates mainly in the liver and brain being excreted by the kidneys. Urinary copper higher than 100ug/24h can be useful in the diagnosis, but only about 20% of Wilson disease patients have abnormal basal levels. In this case, d-penicillamine (DPA) administration can lead, in children, to levels higher than 1.600ug/24h. Twenty five fathers and twenty five mothers of wilson disease patients (mean 61 years for male, and 57 years for female) were assessed in order to obtain urinary copper levels of probable heterozygote adults. Fasting liver enzymes, copper and ceruloplasmin serum levels were obtained along with 24h urinary copper excretion. After, patients got DPA 1.0g by oral route, twice a day, while collecting urine for 24h urinary copper excretion dosage. These analyses were performed by elethrotermic atomic absortion spectrometry method. Liver enzyme levels were similar in men and women but those of alkaline phosphatase were higher in women (M= 68.72 UI/L; F=81.68 UI/L). Serum ceruloplasmin (F=21.72mg/dl; F=27.78mg/dl) and copper (M=71.38 ug/dl; F=88.0 ug/dl) levels were higher in women than in men (p<0.001). Urinary copper levels before DPA were, 43ug/24h (mean) and 21.40 ug/24h (median); and, after DPA, 523.54 ug/24h (mean) and 511.5 ug/24h (median). Basal urinary copper levels in men were 26.9 ug/24h, and in women were 18.67 ug/24h (p=0.005). With the results of this study, we defined a possible range for urinary copper before and after oral intake of DPA in parents of Wilson disease patients. Furthermore, fathers had lower levels of serum copper and of ceruloplasmin, and greater levels of baseline cupriuresis than mothers; and finally the normal range for serum copper and ceruloplasmin, and urinary copper should be differentiated according to the gender.
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Mecanismo de ação da microplusina, um peptídeo quelante de cobre com atividade antimicrobiana. / Action mechanism of microplusin, a copper chelating peptide with antimicrobial activity.Fernanda Dias da Silva 21 October 2008 (has links)
Peptídeos antimicrobianos (PAMs) fazem parte de um dos mecanismos da imunidade inata contra infecções. A microplusina é um PAM de 10.204 Da, isolado da hemolinfa livre de células e dos ovos do carrapato Rhipicephalus (Boophilus) microplus. É um PAM aniônico em pH fisiológico, possui seis resíduos de cisteína, com formação de três pontes dissulfeto, além de sete resíduos de histidina concentrados principalmente na sua porção C-terminal. O presente trabalho teve como objetivo investigar o mecanismo de ação antimicrobiana da microplusina. A microplusina recombinante é ativa contra várias bactérias Gram-positivas e fungos, porém não apresenta atividade contra bactérias Gram-negativas. Para avaliar o seu mecanismo de ação, foram utilizados dois modelos: a bactéria Micrococcus luteus e o fungo Cryptococcus neoformans. A microplusina é bacteriostática contra M. luteus e apresenta localização intracelular na bactéria. Além disso, observamos que a microplusina liga cobre e que a adição deste metal ao meio de cultivo reduz sua atividade antibacteriana. Bactérias M. luteus pré-incubadas com microplusina retomam o seu crescimento quando cobre é adicionado ao meio. Estes dados indicam que a atividade da microplusina está relacionada à sua habilidade de depletar cobre do meio extra ou intracelular, sugerindo um efeito nutricional para o peptídeo. A microplusina apresenta estrutura terciária com cinco a-hélices e sua ligação ao cobre não induz mudanças conformacionais. Observou-se que as histidinas 1, 2 e 74 da microplusina podem estar envolvidas na formação de um sítio de ligação ao cobre. Quanto à C. neoformans, verificou-se que a microplusina inibe a melanização do fungo, um fator de virulência catalisado pela lacase, uma enzima cobre-dependente. Entretanto, a microplusina não afeta a atividade da lacase, nem sua expressão gênica. O peptídeo também não inibe a auto-polimerização de substratos fenólicos que levam à melanização. Sendo assim, mais estudos são necessários a fim de avaliar o mecanismo pelo qual a microplusina inibe a melanização. Adicionalmente, a microplusina afeta a viabilidade do fungo e reduz o tamanho de sua cápsula, outro importante fator de virulência. As atividades da microplusina sobre C. neoformans sugerem o seu potencial terapêutico. Experimentos in vivo com modelo murino, mostraram que a microplusina reduz o processo inflamatório e a viabilidade de C. neoformans nos pulmões, indicando que em condições otimizadas, o peptídeo pode atuar no controle de infecções. / Antimicrobial peptides (AMPs) take part of innate immune mechanisms against infections. Microplusin is a 10,204 Da AMP, isolated from cell-free hemolymph and eggs of the tick Rhipicephalus (Boophilus) microplus. It is an anionic AMP at physiological pH, with six cysteine residues forming three disulfide bridges and seven histidine residues clustered mainly at the carboxy end portion. The goal of the present work was investigate the antimicrobial action mechanism of microplusin. Recombinant microplusin is active against Gram-positive bacteria and fungi, however, no activity is detected for Gram-negative bacteria. Two models were used to evaluate the action mechanism of microplusin: the bacteria Micrococcus luteus and the yeast Cryptococcus neoformans. Microplusin is bacteriostatic against M. luteus and its localization is intracellular for these bacteria. Moreover, microplusin binds copper and the addition of this metal into the medium reduces its antibacterial activity. M. luteus bacteria pre-treated with microplusin recover its growth when copper is added. These data indicate that microplusin activity is related to its ability to deplete copper present in the extracellular or intracellular environment, suggesting a nutritional effect. Microplusin presents a tertiary structure with five a-helix and the copper binding does not induce conformation changes. In addition, it was observed that histidines 1, 2 and 74 from microplusin may be involved in the formation of a copper binding site. About C. neoformans, it was verified microplusin inhibits its melanization, a virulence factor catalyzed by laccase, a copper dependent enzyme. However, microplusin does affect neither laccase activity nor its gene expression. The melanization caused by auto-polymerazation of phenolic substrates, is also not inhibited by microplusin. Hence, additional studies are required to evaluate the mechanism by which microplusin inhibits melanization. In addition, microplusin also affects the fungi viability and reduces the capsule size, another important virulence factor.The microplusin activities against C. neoformans suggest its therapeutic potential. In vivo experiments with murine model showed that microplusin reduces the inflammation and the viability of C. neoformans in the lungs, indicating that, in optimized conditions, the peptide may act in the infection control.
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Approche macromoléculaire pour la décorporation d’actinides / Toward a macromolecular approach for the actinides decorporationLahrouch, Florian 14 December 2017 (has links)
Depuis le développement de l'industrie nucléaire, les risques de contamination humaine avec des actinides subsistent et doivent être pris en considération. Le développement des arsenaux nucléaires, les accidents industriels liés à la filière nucléaire civile (Tchernobyl, Fukushima) ou l’utilisation d’armement à l’uranium appauvri dans les conflits armés (Guerre du Golfe, Kosovo) font des contre-mesures visant à décorporer les actinides chez l'homme un enjeu stratégique majeur. Les actinides sont des éléments radiotoxiques et chimiotoxiques (dont la dangerosité dépend de l'isotopie) qui, en cas d’absorption, peuvent provoquer des dommages (cancers, nécroses, etc.) aux tissus et aux organes qu’ils ciblent (foie, reins, squelette). Actuellement l’efficacité de décorporation du chélatant moléculaire de référence, le DTPA (acide diéthylènetriamine pentaacétique), est limitée par sa faible distribution aux organes touchés par la rétention des actinides. Ce projet de thèse constitue une première étape dans l’exploration d’une stratégie de fonctionnalisation macromoléculaire pour vectoriser les agents chélatants vers ces organes cibles de la rétention des actinides dans le but d’augmenter leur excrétion. Pour initier cette problématique, nous avons choisi de nous intéresser aux capacités de complexation de l’uranyle (U(VI)), du plutonium et du thorium (Pu(IV) et Th(IV)) par deux polyéthylèneimines (PEI) fonctionnalisés avec des groupements carboxylate et phosphonate. L’élaboration des courbes de charge associées à la formation des complexes polymériques d’actinides combinées à des études de spectroscopie EXAFS et IR en milieu pseudo-biologique ont permis de définir les capacités de charge maximale de chaque polymère et de caractériser les sites de complexation. Ces données permettent de mieux comprendre les mécanismes d'affinité des polyéthylèneimines fonctionnalisés pour les actinides considérés et donc de progresser dans le design de décorporants. / Since the development of the nuclear industry, the risks of human contamination with actinides are not to be neglected and should be taken in account. Development of the nuclear weapon programs, nuclear plant accidents from civil use (Chernobyl, Fukushima) or use of depleted uranium ammunitions in war zones (Gulf War, Kosovo) have made countermeasures to decorporate actinides in humans an important strategic issue. Actinides are radiotoxic and chemotoxic elements (the relative dangerousness of which depends on their isotopy) which, if absorbed, can cause damages to the tissues and organs they target (bone, liver cancers or necrosis, etc.). To date the efficiency of the molecular decorporation agent of reference, DTPA (diethyleneiminetriamine pentaacetic acid), is limited by its weak distribution rate to the target organs (bone, liver, kidneys). This project explores the possibility to enhance the actinide body excretion using a targeting strategy of the decorporation agent towards the target organs. To initiate this question, we have chosen to focus on the complexing capacities of uranyl (U (VI)), plutonium and thorium (Pu (IV) and Th (IV)) by two polyethyleneimines (PEI) functionalized with carboxylate and phosphonate groups. The measurement of the uptake curves associated with the formation of the actinide polymer complexes combined with EXAFS and IR spectroscopic studies in a pseudo-biological medium made it possible to define the maximum loading capacities of each polymer and to characterize the complexation sites. These data allow to better understand the mechanisms of affinity of the functionalized polyethyleneimines for the above actinides and thus to progress in the design of new decorporation agents.
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Извлечение тяжелых цветных металлов из шламов нейтрализации отработанных электролитов : магистерская диссертация / Recovery of heavy non-ferrous metals from sludges of spent electrolytes neutralizationНапольских, Ю. А., Napol’skikh, Y. A. January 2018 (has links)
В данной работе проведено исследование переработки мышьяксодержащих шламов нейтрализации отработанных электролитов с целью селективного извлечения ценных металлов (медь, никель). Для определения химического и фазового анализа техногенного многокомпонентного сырья применены методы спектрофотометрии (AAС) и рентгенофазовой дифрактоскопии. Предложен выщелачивающий комплексообразующий реагент Трилон Б и обоснован его выбор. Проведены литературный обзор современных методов переработки, лабораторные исследования. Исследованы и оптимизированы процессы выщелачивания шламов водным раствором Трилона Б, очистки полученного трилонатного раствора от металлов-примесей, регенерации растворителя. Так же в диссертации выбрана оптимальная схема переработки гидроксидных шламов и отражено эколого-экономическое обоснование выбранной технологии переработки. / In this paper, research arsenic-containing slimes of neutralization of waste electrolytes was carried out to selectively extract valuable metals (copper, nickel). The method of Atomic Absorption Spectroscopy (AAS), X-ray Diffraction (XRD) was applied. The chemical and phase analysis of multicomponent manmade waster was carried out, the leaching chelating reagent Trilon B was offered and its choice is reasonable. A review of modern methods of processing and laboratory studies were carried out. The processes of leaching of slimes by aqueous solution of Trilon B, purification of the obtained trilonate solution from metal-impurities and solvent regeneration were studied and optimized. Also, in the thesis the optimal scheme of processing of hydroxide sludges was chosen and the ecological and economic justification of the chosen technology of processing was represented.
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Carbon dioxide sequestration: Chemical and physical activation of aqueous carbonation of Mg-bearing minerals and pH swing processPark, Ah-Hyung Alissa 24 August 2005 (has links)
No description available.
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Bifunkční chelatanty pro selektivní komplexaci mědi / Bifunctional chelators for selective copper(II) bindingPaúrová, Monika January 2012 (has links)
Title: Bifunctional chelators for selective copper(II) binding Autor: Bc. Monika Paúrová Department: Department of Inorganic Chemistry, Faculty of Science Supervisor: doc. RNDr. Jan Kotek, Ph.D. Supervisor's e-mail: modrej@natur.cuni.cz Abstract: In this Master thesis, cyclam bifunctional derivatives bearing pendant phosphinate groups (4-methyl-11-p-aminobenzyl-1,4,8,11-tetraazacyclotetradecane-1,8- bis(methylenephosphinic acid)) and phosphonate groups (4-methyl-11-p-aminobenzyl- 1,4,8,11-tetraazacyclotetradecane-1,8-bis(methylenephosphonic acid)), were prepared and studied as potential ligands for complexation of divalent copper. These ligands are suitable for binding to a macromolecular carrier. Keywords: radiomedicine, copper, cyclam, chelating agent, phosphinate, phosphonate, kinetic inertness, kinetic lability, thermodynamic stability
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