Made available in DSpace on 2015-03-26T13:53:29Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2270439 bytes, checksum: f1f5ac7a173bd54b51ef49f193fb1448 (MD5) Previous issue date: 2013-03-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Lanthanum is one of the 17 chemical elements known as rare earths. The increasing use of these metals by industries and impacts of mining have contributed to their mobility in the environment, creating possible environmental hazards and health effects. In this study, we evaluated the La removal from aqueous solution through the synthesis of iron and aluminum colloids via precipitation and the retention of this contaminant in the solid phases formed. Solutions of ferrous sulfate, aluminum sulfate and lanthanum sulfate were mixed in different proportions, in polyethylene containers, so as to obtain ten Fe: Al: La molar ratios(500:125:0, 500:125:1, 500: 125:5, 500:125:25, 500:125:125, 500:250:0, 500:250:1, 500:250:5, 500:250:25 and 500:250:125). The experimental period was 90 days. Supernatant aliquots were collected to determine lanthanum concentration weekly. The precipitated material was characterized by color determination by the Munsell system, X-ray diffraction (XRD), scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS). Potential remobilization of lanthanum in the solid phases formed was evaluated by comparing the amounts extractable by acetic acid 0.11 mol L-1 with the total contents, both determined by ICP OES. High efficiencies in lanthanum removal from aqueous phase were obtained. The precipitate colors tended to redden with the increments in lanthanum amount. The XRD detected the formation of Al-goethite in most treatments and other phases such as Al-lepidocrocite and Al-magnetite, in specific cases. Microanalysis revealed the lanthanum association to iron and aluminum colloids in the solid phase and the occurrence of segregation where the element was more abundant. The extractions with acetic acid showed high potential remobilization of lanthanum to most treatments. The method is suitable for removing the contaminant from water, but further studies are necessary to optimize retention in the solid phase. / O Lantânio é um dos 17 elementos químicos conhecidos como terras raras. A intensificação do uso desses metais pelas indústrias e impactos decorrentes da mineração têm contribuído para uma maior mobilidade desses elementos no ambiente, gerando riscos ecológicos e à saúde humana. Neste trabalho, avaliou-se a remoção de La de solução aquosa por meio da síntese de coloides de ferro e alumínio via precipitação e a retenção do contaminante nas fases sólidas formadas. Soluções de sulfato ferroso, sulfato de alumínio e sulfato de lantânio foram misturadas em diferentes proporções, em recipientes de polietileno, de modo a obter dez relações molares Fe:Al:La (500:125:0, 500:125:1, 500:125:5, 500:125:25, 500:125:125, 500:250:0, 500:250:1, 500:250:5, 500:250:25 e 500:250:125). O período experimental foi de 90 dias. Semanalmente foram coletadas alíquotas do sobrenadante para determinação da concentração de lantânio. O material precipitado foi caracterizado por meio de determinação de cor pelo sistema Munsell, difratometria de raios X (DRX), microscopia eletrônica de varredura e espectroscopia de energia dispersiva (MEV/EDS). O potencial de remobilização de lantânio nas fases sólidas formadas foi avaliado por comparação dos teores extraíveis por ácido acético 0,11 mol L-1 com os teores totais, ambos determinados em ICP OES. Elevadas eficiências na remoção de lantânio da fase aquosa foram obtidas. A coloração dos precipitados tendeu a avermelhar-se com os incrementos na quantidade de lantânio. A DRX detectou a formação de Al-goethita na maioria dos tratamentos e outras fases, como Al-lepidocrocita e Al-magnetita, em casos específicos. A microanálise evidenciou a associação do lantânio aos coloides de ferro e alumínio nas fases sólidas e a ocorrência de segregação onde o elemento era mais abundante. As extrações com ácido acético revelaram alto potencial de remobilização de lantânio para a maioria dos tratamentos. O método seria adequado para a remoção do contaminante da solução aquosa, porém ainda são necessários estudos para otimizar a retenção na fase sólida.

Nós estudamos o controle estrutural dos veios de pegmatitos graníticos (tipo F-ETR-Li) associados à fácies albita granito (AEG) do granito Madeira (~1.83Ga). Esta fácies corresponde ao depósito, de classe mundial, de Sn-Nb-Ta-F (criolita) da mina de Pitinga. Atualmente, esses pegmatitos ricos em ETR (xenotima e gagarinita) são explorados junto com o minério disseminado, porém possuem potencial para exploração por lavra seletiva. Todos os pegmatitos possuem arranjo geométrico e mineralogia similares, o que sugere mesma fonte. Também possuem mineralogia igual à da encaixante e seu alojamento ocorreu na própria rocha parental. O arranjo geométrico dos pegmatitos foi controlado por estruturas contracionais frágeis (falhas inversas, leques de imbricação e cavalos). Os planos de falhas inversas (N320/60SW) serviram como condutos para o fluido que se alojou preferencialmente em fraturas horizontais distensivas. O arranjo geométrico bem definido dessas estruturas e o fato de que também há planos de falhas inversas sem pegmatitos demonstram que as fraturas que hospedam os pegmatitos não foram formadas pela pressão do fluido. A orientação das estruturas contracionais no AEG indica que ocorreu um transporte de SW para NE. Como este corpo possui pequena dimensão, resfriou-se rapidamente. Contudo, sua localização na crosta superior fria e a baixa temperatura solidus permitiram a formação dos pegmatitos. No nível estrutural em que se encontram os pegmatitos estudados, quando esses veios se alojaram, o AEG estava cristalizado e posicionado acima da profundidade crustal crítica, onde o estresse normal mínimo é vertical. / We study the structural control of pegmatites (F-REE-Li vein-type granite pegmatite) associated to the albite-enriched granite facies (AEG) of the Madeira A-type granite (~1.83 Ga). This facies corresponds to the Madeira world-class Sn-Nb-Ta-F (cryolite) deposit at the Pitinga mine. These REE-rich pegmatites (xenotime and gagarinite), presently exploited together with the disseminated ore, have potential to explotation by selective mining. They have a common geometric arrangement and share a same mineralogy, therefore they all originate from the same source. They have the same mineralogical composition of the host rock and their emplacement occurred in the parental rock itself. The geometric arrangement of the pegmatites is settled by contractional brittle structures (reverse faults, imbrication fans and horses). The reverse fault planes (~N320/60SW) were essentially the conduits for the fluid. The preferential sites for the pegmatites bodies were the horizontal tensile fractures. The well-marked geometric arrangement of the tectonic structures and the fact that there are also reverse faults planes without pegmatites show that the fractures that host the pegmatites were not formed by the fluid pressure. The orientation of the contractional structures in the AEG indicates a transport from SW to NE. With reduced surface dimensions, the AEG cooled fast, however its location in the cold upper crust and the low solidus temperature allowed pegmatites formation. At the structural level of the studied pegmatites, when these veins positioned, the AEG was crystallized in a position above the critical crustal depth, where minimum normal stress is vertical.

À l’origine, les Terres Rares (TR) sont utilisées pour tracer les processus géochimiquesnaturels. Depuis quelques années, elles sont de plus en plus utilisées par l'industrie, la médecine etl'agriculture. Cette utilisation croissante entraîne de nouveaux risques et nous amène à considérerles TR comme des polluants émergents. Dans ce contexte, ce travail de thèse propose une étude dela mobilité et de la répartition des TR dans le système sol-plante, ainsi que leur effet sur lavégétation. La première partie de ce document présente l'approche de terrain employée, soit le choixde sites non pollués avec des contextes géologiques différents (calcaire, granitique et carbonatique),afin de comparer les transferts et la répartition des TR en milieu naturel. La deuxième partie de cemanuscrit est orientée vers une approche en milieu contrôlé, permettant d'étudier l'effet des TR surla germination et la croissance des plantes.Les résultats indiquent que les concentrations en TR ne reflètent pas directement lesconcentrations de la roche, dans la mesure où elles apparaissent dépendantes des processuspédologiques et des teneurs en phases minérales riches en TR. Les sols présentent tous unenrichissement en TR lourdes lié aux complexes formés à partir des TR lourdes et des oxydes defer. La végétation, quant à elle, présente systématiquement un enrichissement en TR légères,résultant en partie de cette liaison entre TR lourdes et oxydes de fer. Les TR montrent un fort lienavec le fer dans le continuum sol- végétation, indiquant que les processus pédologiques etphysiologiques à l’origine de l'absorption des TR, sont étroitement liés à ceux du Fe. Le transfertdes TR dans la plante entraîne leur accumulation dans le système racinaire, où elles seront bloquéespar la bande de Caspary. Ce phénomène limite alors le transfert vers les organes aériens via le fluxnutritif. Les concentrations en macro-éléments de ce flux nutritif pourraient être influencées par laprésence de fortes concentrations de TR dans les racines. L'application de fortes concentrations enTR influencent également la germination et la croissance racinaire des végétaux. / Background and aims Rare Earth Elements (REE) are widely used to trace naturalgeochemical processes. They are also increasingly used by man (electronics industry, medicine,agriculture) and therefore considered as emerging pollutants. The present documents studies REEmobility in non-polluted natural soil-plant systems in order to characterize their environmentalavailability for future anthropogenic pollution. The first part of this thesis is based on a fieldapproach in non-polluted natural sites with contrasting geological environments (limestone, granite,and carbonatite) and highly variable REE contents. The second part consist in an experimentalapproach under controlled conditions, in order to study REE’s effect on vegetation.REE concentrations in soils do not directly reflect bedrock concentrations, but dependlargely on pedogenetic processes and on the mineralogy of bedrock and soil. The soils of all sitesare with respect to bedrock enriched in heavy REE. The REE uptake by plants is not primarilycontrolled by the plant itself, but depends on the concentration and the speciation in the soil and theadsorbed soil water pool. REE uptake by plant roots are linked with those of Fe. Roots absorbpreferentially the light REE. Before translocation, REE are retained by the Casparian strip leadingto much lower concentrations in the aerial parts. The transport of the REE within the xylem isassociated with the general nutrient flux. This nutrient flux could be affected by the addition of highREE concentrations. Thus, the presence of high REE concentrations in the environment has anegative effect on the germination and the roots growth.

Nós estudamos o controle estrutural dos veios de pegmatitos graníticos (tipo F-ETR-Li) associados à fácies albita granito (AEG) do granito Madeira (~1.83Ga). Esta fácies corresponde ao depósito, de classe mundial, de Sn-Nb-Ta-F (criolita) da mina de Pitinga. Atualmente, esses pegmatitos ricos em ETR (xenotima e gagarinita) são explorados junto com o minério disseminado, porém possuem potencial para exploração por lavra seletiva. Todos os pegmatitos possuem arranjo geométrico e mineralogia similares, o que sugere mesma fonte. Também possuem mineralogia igual à da encaixante e seu alojamento ocorreu na própria rocha parental. O arranjo geométrico dos pegmatitos foi controlado por estruturas contracionais frágeis (falhas inversas, leques de imbricação e cavalos). Os planos de falhas inversas (N320/60SW) serviram como condutos para o fluido que se alojou preferencialmente em fraturas horizontais distensivas. O arranjo geométrico bem definido dessas estruturas e o fato de que também há planos de falhas inversas sem pegmatitos demonstram que as fraturas que hospedam os pegmatitos não foram formadas pela pressão do fluido. A orientação das estruturas contracionais no AEG indica que ocorreu um transporte de SW para NE. Como este corpo possui pequena dimensão, resfriou-se rapidamente. Contudo, sua localização na crosta superior fria e a baixa temperatura solidus permitiram a formação dos pegmatitos. No nível estrutural em que se encontram os pegmatitos estudados, quando esses veios se alojaram, o AEG estava cristalizado e posicionado acima da profundidade crustal crítica, onde o estresse normal mínimo é vertical. / We study the structural control of pegmatites (F-REE-Li vein-type granite pegmatite) associated to the albite-enriched granite facies (AEG) of the Madeira A-type granite (~1.83 Ga). This facies corresponds to the Madeira world-class Sn-Nb-Ta-F (cryolite) deposit at the Pitinga mine. These REE-rich pegmatites (xenotime and gagarinite), presently exploited together with the disseminated ore, have potential to explotation by selective mining. They have a common geometric arrangement and share a same mineralogy, therefore they all originate from the same source. They have the same mineralogical composition of the host rock and their emplacement occurred in the parental rock itself. The geometric arrangement of the pegmatites is settled by contractional brittle structures (reverse faults, imbrication fans and horses). The reverse fault planes (~N320/60SW) were essentially the conduits for the fluid. The preferential sites for the pegmatites bodies were the horizontal tensile fractures. The well-marked geometric arrangement of the tectonic structures and the fact that there are also reverse faults planes without pegmatites show that the fractures that host the pegmatites were not formed by the fluid pressure. The orientation of the contractional structures in the AEG indicates a transport from SW to NE. With reduced surface dimensions, the AEG cooled fast, however its location in the cold upper crust and the low solidus temperature allowed pegmatites formation. At the structural level of the studied pegmatites, when these veins positioned, the AEG was crystallized in a position above the critical crustal depth, where minimum normal stress is vertical.

Rare earth elements (REEs) are critical materials in many electronics and green technology products. Though the demand for REEs is growing rapidly, China controls over 90% of the REEs supply and the US currently is not producing any REEs. As most of the REEs occurred together in the mineral ores with low concentrations and they have similar chemical and physical properties, the extraction and purification processes are challenging. Conventional methods for producing REEs require large amounts of toxic chemicals and generate large amounts of hazardous wastes. Therefore, it is important to develop alternative REE sources as well as efficient and environmentally friendly processes to produce REEs domestically. In this dissertation, coal fly ash, a major coal combustion byproduct, was explored as a potential source for REEs. Novel separation and purification methods were developed for producing high purity REEs from class F coal fly ash.<div><br></div><div>First, a sequential separation process was developed to recover and concentrate REEs from class F coal fly ash. The ash was first digested using a NaOH solution and subsequently dissolved in an acid to extract REEs as well as other chemicals. About 74% of REEs, 92 % of SiO2, 74% of Al2O3, 24% of Fe2O3, and 65% of CaO were extracted. Most (>99%) of the extracted REEs and cations (Al+3, Fe+3, Ca+2) were captured in a cation exchange column. Negatively charged Si species were eluted by water. The captured REEs were separated from the other cations in the column. A solution of NaCl was used to elute the cations and most of the REEs, which were strongly adsorbed in the column, were eluted using a solution of diethylenetriaminepentaacetic acid (DTPA). In this separation process, high purity SiO2 (>99%), Al(OH)3 (>99%), and Fe(OH)3 (>95%) were produced. The eluted DTPA-REEs solution was then loaded in a cation exchange column. The REEs accumulated in the column could be further separated into pure REE fractions using a ligand-assisted displacement chromatography method (LAD), instead of the conventional liquid-liquid extraction method.<br></div><div><br></div><div>Detailed rate model simulations were developed for LAD and verified with experimental and literature data. The dynamic column profiles in simulations showed that a prestaurant which has a higher ligand affinity and a lower sorbent affinity than REEs is required to develop an isotachic train in LAD. When a constant-pattern isotachic train is developed, high concentration bands with high purity and high yield can be achieved. Further increase in column length is not needed. Thus, if purity, yield, sorbent, and ligand are fixed, the constant-pattern state gives the highest sorbent productivity and the highest ligand efficiency. It is critical to develop a method to find the general conditions required for developing constant-pattern states. Key dimensionless parameters affecting the constant-pattern states were formulated first based on the h-transformation theory for an ideal system and the shock layer theory for a nonideal system. Strategetic combinations of the key dimensionless groups were developed to express a dimensionless mininum column length as a function of the combined dimensionless groups. Rate model simulations were used to find various minimum column lengths for developing constant-pattern states from transient states. The simulation results were used to generate a correlation curve in a two-dimensional plot or map where the curve divided the map into two regions, the transient region, and the constant-pattern region. The map can be used to find the minimum required conditions for developing a constant-pattern state for a general LAD system at any scale.<br></div><div><br></div><div>A constant-pattern design method for both ideal and non-ideal (with significant mass transfer effects) LAD systems was developed based on the general correlation equation for the map. In addition, an equation for the yield of a target component as a function of the key dimensionless groups was derived based on the constant-pattern mass transfer zone lengths. The column length and operating velocity solved from the two equations ensured the yields and the constant–pattern state for the target components. A selectivity weighted composition factor was developed to allow the design method to specify a minimum target yield for one or multiple components. The design method is robust and scalable because it provides the optimal operating conditions to meet the minimum target yield and purity of one or multiple components for LAD systems at any scale. The design method was verified using simulations and experiments for different target yields, ligand concentrations, and feed compositions for ternary mixtures. The minimum target yields were achieved or exceeded in all cases tested. The results showed that high ligand concentration, long column length, and high effective sorbent selectivity can increase sorbent productivity. The minimum column length required to achieve a constant-pattern state and the productivity of LAD are limited by the lowest selectivity or by a minority component with a low concentration in the feed, even when it does not have the lowest selectivity. If both minor and major REE components in a mixture need to be recovered in the same LAD process, the overall productivity could be significantly limited. Thus, separating major components first and recycling/separating the minor components in a separate LAD process could increase the total productivity significantly. The productivities achieved using this design method are two orders of magnitude higher than the literature results with similar REE yields and purities.<br></div>

Die Wasserverschmutzung durch Seltenen Erden (REEs) und Schwermetallen verursacht viele Probleme für die Umwelt und die menschliche Gesundheit. Daher ist der Nachweis solcher Elemente von hoher Priorität. Derzeit verwendete Methoden haben einige Nachteile, wie hohe Messkosten, beschränke Selektivität, komplexe Handhabung oder der Bedarf von hochqualifiziertem Personal für die Probenanalyse. Die Kombination von biologischen Komponenten und Nanomaterialien zur Sensorentwicklung bietet eine Möglichkeit diese Nachteile ausgleichen. Mikroorganismen haben evolutionäre Strategien entwickelt, um sich vor toxischen Schwermetallen zu schützen, z.B durch Binden der Metallionen an ihrer Zelloberfläche mit speziellen Oberflächenproteinen (S-Layer). Diese bestehen aus einer Monolage identischer (Glyco-) Proteine, die sich selbst assemblieren und eine hochgeordnete kristalline Struktur unterschiedlicher Symmetrie bilden können. Studien haben die Bindung von Metallionen (einschließlich REEs) durch S-Layer-Proteine gezeigt. In dieser Dissertation wurden drei Nanomaterialien (Goldnanopartikel (AuNPs), planare Goldoberflächen und Nanodiamanten (NDs)) mit acht verschiedene S-Layer-Proteinen beschichtet. Ziel war die Entwicklung von Biohybrid-Sensor-Systemen für die Detektion von bis zu 12 Metallionen in Wasser. Ein kolorimetrisches Sensorsystem mit biofunktionalisierten AuNPs zur Detektion von REEs und Schwermetallen, einschließlich der aktuell vermehrt auftretenden Schadstoffe Lanthan und Gadolinium, wurde etabliert. Die Nachweisgrenzen lagen im Bereich vergleichbarer AuNPs-Systeme zum Nachweis von Schwermetallen, während die Slayer-AuNP-Biohybride ein breiteres Spektrum von Metallionen detektieren konnten. Das Screening aller acht S-Layer-AuNP-Biohybride mit 12 Metallsalzlösungen ergab charakteristische Wechselwirkungsmuster für jede der Kombinationen und ermöglichte den spezifischen Nachweis einer einzelnen Metallionenspezies in unbekannten Lösungen. Eine Kosten- und Ressourcenoptimierung ist über die Lagerung bis zu drei Monate und Wiederverwendbarkeit gegeben. Auf planaren Goldoberflächen ermöglichten die SPR-Spektroskopie die Messung der Adsorption von S-Layer-Proteinen, sowie die anschließende Detektion von CuSO4, NiCl2 und YCl3. Die Detektionslimits lagen dabei unter den kolorimetrischen Biohybridsystemen. Die SPR-Chips wurden erfolgreich regeneriert und für mehrere Funktionalisierungen mit S-Layer-Proteinen wiederverwendet. Das S-Layer-Protein SslA von S. ureae ATCC 13881 wurde erstmals an NDs adsorbiert. Die NDs/SslA-Biohybride wurden zur Detektion von CuCl2 und NiCl 2 verwendet, indem die Agglomeration und das Fluoreszenzquenching gemessen wurden. Es hat sich gezeigt, dass die vorgestellten Systeme viele der Nachteile ausgleichen, die mit derzeit verwendeten Systemen verbunden sind. Sie detektieren eine Vielzahl von Metallionen und minimieren so den Bedarf für mehrere Methoden. Die Nachweisgrenzen waren vergleichbar mit aktuellen kolorimetrischen und chemischen Kit-Systemen. Die S-layer-AuNPs und NDs/S-layer-Biohybride waren schnell und einfach zu handhaben, wodurch der Bedarf an hochqualifiziertem Messpersonal minimiert werden kann. Darüber hinaus führt die Verwendung von kostengünstigen Materialien wie NDs und die Wiederverwendbarkeit der Biohybride zu einem ressourceneffizienten und kostengünstigen Nachweissystem. Diese Dissertation hat das enorme Potenzial von S-Layer-Proteinen für den Nachweis von REEs und Schwermetallen in Wasser unter Verwendung verschiedener Nachweissysteme wie kolorimetrischer AuNPs-Assays, SPR-Spektroskopie und NDs gezeigt. / The pollution of aqueous systems with rare earth elements (REEs) and heavy metals causes serious problems for environmental and human health. Therefore, the detection of such elements is of uttermost importance. Currently used methods have some disadvantages, such as high measurement costs, limited selectivity, complex sample handling, or the need for highly qualified personnel for sample analysis. The combination of biological components and nanomaterials for sensor development offers a way to offset these disadvantages. Microorganisms have developed strategies to protect themselves from heavy metal toxicity, e.g. by binding the metal ions on their cell surface with special Surface layer (S-layer) proteins. They consist of a monolayer of identical (glyco-) proteins, which can self-assemble and form a highly ordered crystalline structure of varying symmetry. Studies on the heavy metal binding of S-layer proteins have demonstrated their affinity for metal ions, including REE. The combination of nanomaterials with S-layer proteins enables the development of new sensors for these elements. Within this dissertation several nanomaterials in combination with S-layer proteins were investigated to obtain sensors for REEs and heavy metals. Eight different S-layer proteins were used to functionalize AuNPs, flat gold surfaces and nanodiamonds (NDs) for the detection of up to 12 metal ions in water. Colorimetric sensor systems with biofunctionalized AuNPs for the detection of REE and heavy metals, including the newly emerging pollutants lanthanum and gadolinium, were established. The detection limits of reference measurements and spiked tapwater samples were in the range of comparable AuNPs systems for the detection of heavy metals, while offering a broader range of metal ions to detect. The screening of all eight S-layer-AuNP biohybrids with 12 metal ions revealed specific interaction patterns for each of the combinations. The optimization cost and resource is achieved by storage up to three months and reusability of the S-layer-AuNP biohybrids. Surface plasmon resonance (SPR) spectroscopy enabled the measurement of S-layer proteins binding to flat gold surfaces, resulting in a stable protein layer used for the subsequent detection of CuSO4, NiCl2 and YCl3. The SPR chips were succesfully regenerated and reused for multiple functionalizations with S-layer proteins. The S-layer protein SslA from S. ureae ATCC 13881 was successfully adsorbed to the pristine NDs by physical conjugation. The NDs/SslA conjugates were used for the detection of CuCl2 and NiCl2, by measuring the agglomeration of the NDs and fluorescence quenching. The presented systems compensate many of the disadvantages associated with currently used techniques. They detect a broad variety of metal ions, minimizing the need for multiple methods. The detection limits were comparable to current colorimetric and chemical kit systems. The S-layer-AuNPs and NDs/S-layer biohybrids were quick and easy to handle, minimizing the need for highly qualitified personnel. In addition, the use of cost-effective materials such as NDs and the reusability of the biohybrids results in resource-efficient and cost-effective sensor systems. This project has shown the tremendous potential of S-layer proteins for the detection of REE and metal ions in water, by utilizing different detection systems like colorimetric AuNPs assays, SPR spectroscopy and NDs.

No description available.

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Sällsynta jordartsmetaller är en kritisk råvara som står inför viktiga utmaningar gällande utbud och efterfrågan. För att överkomma dessa utmaningar behövs det effektiva separationsmetoder. Den här rapporten studerar separationen av sällsynta jordartsmetaller med extraktionskromatografi. Tre olika extrakt-modifierade HPLC kolonner användes för att separera en samling av åtta sällsynta jordartsmetaller; lantan, cerium, praseodym, neodym, samarium, gadolinium, dysprosium och yttrium. Den första kolonnen innehöll ren HDEHP som extraktant, den andra ren HEHEHP som extraktant. Den tredje kolonnen innehöll en blandning av de två extrakanterna. Blandningen bestod av 15–30% HDEHP. Eluering genomfördes med salpetersyra i olika koncentrationer och applicering. Forskningsfrågan som rapporten bygger på gäller hurvida blandningen av extraktanterna kan förbättra separationen gentemot att endast använda de rena extraktanterna. Jämförelsen kolonnerna emellan baserades huvudsakligen på två parameterar, salpetersyraförbrukning och upplösning av toppar.  Resultaten visar att kolonnen med endast HEHEHP hade minst salpetersyraförbrukning men gav sämst upplösning. Kolonnen med endast HDEDP hade högst salpetersyraförbrukning men gav bäst upplösning, speciellt för de fyra tyngsta ämnena; samarium, gadolinium, dysprosium och yttrium. Kolonnen med extraktantblandningen gav god upplösning för alla ämnen, speciellt för de fyra lättaste ämnena; lantan, cerium, praseodym och neodym. Eftersom denna kolonn dessutom hade relativt låg salpetersyraförbrukning är den preliminära slutsatsen att denna presterade bäst generellt. Slutsatsen är därmed att extraktantblandningen kan förbättra separationen. / Rare earth elements are a crucial resource facing challenges concerning supply and demand. To meet these challenges, efficient separation methods are needed. This report investigates the separation of rare earth elements using extraction chromatography. Three different extractant modified HPLC columns was used to separate a collection of eight rare earth elements: lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, dysprosium, and yttrium. One column contained pure HDEHP as extractant, another pure HEHEHP as extractant. The third column contained mixture of the two extractants. The mixture contained 15-30% HDEHP. Elution was achieved using nitric acid as eluent in different concentrations and modes of elution. The research question guiding the work was to investigate if using a mixture of extractants could improve the separation as opposed to using only the pure extractants. The comparison was made based on two main performance parameters, nitric acid consumption and peak resolution.  The results show that the column with pure HEHEHP had the lowest nitric acid consumption but yielded the worst resolution. The column with pure HDEHP had the highest nitric acid consumption but the best resolution, particularly for the four heaviest analytes, samarium, gadolinium, dysprosium, and yttrium. The column with the extractant mixture yielded good resolution for all analytes and especially for the four lightest analytes: lanthanum, cerium, praseodymium, and neodymium. Since this column also had relatively low nitric acid consumption the tentative conclusion is that it performed the best overall. The conclusion is therefor that the extractant mixture can improve the separation.

Nous avons développé une méthode pour analyse isotopique de Yb et Er, deux terres rares aux propriétés chimiques identiques et aux températures de condensation différentes, avec comme objectifs (1) de déterminer la variabilité isotopique de ces éléments dans les processus pétrologiques terrestres, et (2) de comparer leurs compositions isotopiques dans les chondrites, la Terre et la Lune afin de déterminer le rôle potentiel de la condensation à haute température à partir de vapeurs qui a suivi l’impact géant à l’origine de la formation de la Lune. Les résultats obtenus montrent une plus grande variabilité des fractionnements isotopiques de Yb par rapport à ceux d’Er. Deux effets contribuent à cette différence : un effet oxydo-réducteur et un effet de température. La corrélation positive obtenue entre la composition isotopique en Yb, et le rapport La/Yb dans les échantillons terrestres, peut être interprétée par la présence d’une faible fraction d’ Yb(2+), Yb étant majoritairement présent sous la forme Yb(3+). La kimberlite (liquide magmatique formé par un faible taux de fusion partielle) est enrichie en isotopes lourds et les grenats, résidus de fusion partielle, sont isotopiquement légers, tandis que les basaltes de ride ou d’îles ont des compositions isotopiques intermédiaires.La composition isotopique en Yb de la Lune est enrichie en isotopes légers par rapport à celle de la Terre et des chondrites. Dans le disque proto-lunaire, les frictions entre les phases fondues et gazeuses favorisent la migration des premiers condensats très réfractaires et enrichis en isotopes lourds vers la Terre, et celle de la vapeur enrichie en isotopes légers, vers l’extérieur, au-delà de la limite de Roche à partir de laquelle la Lune s’accrète. Ceci est un nouvel argument en faveur de la condensation de la Lune à partir de vapeur générée par un impact géant. La mesure de la composition isotopique d’Er dans les échantillons lunaires reflète pour la première fois la capture par 167Er des neutrons produits par interaction du rayonnement cosmique galactique avec la surface lunaire. L’apport de Er aux systèmes communément utilisés pour déterminer le spectre d’énergie des neutrons d’un matériau peut permettre de couvrir une gamme énergétique plus large et de disposer ainsi d’un proxy plus complet pour l’étude des histoires des irradiations des matériaux planétaires. / Er and Yb are two refractory rare-earth elements that have overall similar crystallochemical properties but differ in their temperatures of condensation from the nebular gas. We developed an analytical protocol for the measurement of Er and Yb isotope compositions 1) to establish their isotopic variability in terrestrial magmatic processes 2) to compare their isotopic composition in chondrites, Earth and Moon in order to study fractionation during the high temperature condensation of vapor formed by the giant impact that generated the Moon. The range of mass-dependent isotope fractionation obtained is larger for Yb than Er isotopes. Two effects contribute to the difference between Er and Yb : a redox effect and a temperature effect.First, for terrestrial rocks, the presence of a small fraction of Yb(2+) together with the most common Yb(3+) is inferred from the positive corre- lation between δYb and the La/Yb ratio. Yb(3+) fractionates favorably into tighter bonds and, at the same time, is much more compatible than Yb(2+). Small-degree melts (kimberlite) tend to be enriched in the heavy Yb isotopes, whereas the opposite is true for residual garnets. Second, the stronger volatility of Yb with respect to Er is demonstrated by the apparent deficit of heavy Yb isotopes in the Moon with respect to the Earth, chondrites, and eucrites. Separation of vapor from melt and of heavy from light isotopes is first expected during the adiabatic expansion of the initial vapor plume. Subsequently, friction between melt and gas tends to further enrich the Moon feeding zone in silicate vapor to compensate the inward migration of melt out of the pre-lunar disk. The lighter isotope composition of Yb in lunar samples provides new evidence that the Moon formed by condensation of silicate vapor in the aftermath of the giant lunar impact.Erbium isotope ratios in lunar samples reflect for the first time the capture by 167Er of secondary neutrons produced by interactions of galactic cosmic rays with the lunar surface. The cross section of 167Er for neutron capture being particularly strong and its first resonance standing out at energies poorly covered by other nuclides, 167Er anomalies may help refine the knowledge of the neutron energy spectrum on the Moon and other planetary bodies.