The field of analytical chemistry is very important to today's society as more and more regulations and legislations emerge regarding trace elements in food, consumer products, medicines, and the environment. Like many areas of science, the current goals of trace elemental measurements and speciation are to increase knowledge on the subject and to improve upon current techniques by enhancing the figures of merit, such as accuracy and reproducibility, meanwhile balancing with the cost and time of analysis. The topics covered in this work were investigated primarily through the use of inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The phenomenon of compound-dependent responses in plasma spectrometry is discussed, seeking possible causes of it and offering some advice on how to prevent it. A new method was developed for the speciation of selenium in dietary supplements using anion-exchange chromatography ICP-MS. A novel method for the determination of total mercury at trace concentrations in rice was developed for use with conventional ICP-MS. Inductively coupled plasma mass spectrometry was also used for fingerprinting the rare earth elements in Maya archaeological pottery for provenance studies.

The rapid development of advanced technologies has led to an increase in demand for critical elements that are essential in the manufacturing of high-tech products. Among these critical elements, manganese (Mn), cobalt (Co), and nickel (Ni) are used in the production of batteries, electronics, and other advanced applications. The demand for these elements has been growing exponentially in recent years, driven by the rise of electric vehicles, renewable energy, and other emerging technologies. However, the United States is heavily dependent on foreign sources of critical minerals and on foreign supply chains, resulting in the potential for strategic vulnerabilities to both economy and military. To address this problem and reduce the Nation's vulnerability to disruptions in the supply of critical minerals, it is important to develop critical minerals recycling technologies. A systematic study was conducted to develop a process for producing high-purity Mn, Co, and Ni products from an acid mine drainage (AMD). As major contaminants, Fe and Al in the solution were sequentially precipitated and eliminated by elevating the pH. After that, a pre-concentrated slurry containing Mn, Co, Ni, and Zn was obtained by collecting the precipitates formed in the pH range of 6.50 to 10.00. The pre-concentrated slurry was redissolved for further purification. Sodium sulfide was added into the redissolved solution to precipitate Co, Ni, and Zn selectively while retaining Mn in the solution. Almost 100% of Co, Ni, and Zn but only around 15% of Mn were precipitated using a sulfur-to-metal molar ratio of 1 at pH 4.00. The sulfide precipitate was calcined and then completely dissolved. The critical elements existing in the dissolved solution were efficiently separated using a two-stage solvent extraction process. Ultimately, Co and Ni products with almost 94% and 100% purity were obtained by sulfide and alkaline precipitation, respectively. AMD also contains rare earth elements (REEs), which can be recovered through selective chemical precipitation. REE removal improved at pH 4.0 after converting ferrous to ferric ions with H2O2. Aluminum species in the solution hindered REE adsorption on ferric precipitates, and ferrous ions reduced REE adsorption on aluminum precipitates at lower pH, but at higher pH, REE removal increased due to ferrous ion precipitation. Various tests and analyses were conducted to understand the partitioning mechanisms of REE during the precipitation process of AMD. Sulfide precipitation is crucial to separate Mn from other elements, but the presence of contaminants like Fe and Al can affect sulfide precipitation efficiency. The effects of Al3+ iii and Fe2+ on the precipitation characteristics of four valuable metals, including Mn2+, Ni2+, Co2+, and Zn2+, were investigated by conducting solution chemistry calculations, sulfide precipitation tests, and mineralogy characterizations. It was found that the ability of the valuable metals to form sulfide precipitates followed an order of Zn2+ > Ni2+ > Co2+ > Mn2+. The sulfide precipitate of Zn2+ was the most stable and did not re-dissolve under the acidic condition (pH 4.00 ± 0.05). In addition, the sulfide precipitation of Zn2+ was barely affected by the contaminant metal ions. However, in the presence of Al3+, the precipitation recoveries of Mn2+, Ni2+, and Co2+ in a solution containing all the valuable metals were noticeably reduced due to simultaneous hydrolysis and competitive adsorption. The precipitation recoveries of Ni2+ and Co2+ in solutions containing individual valuable metals also reduced when Fe2+ was present, primarily due to competitive precipitation. However, the recovery of Mn2+ was enhanced due to the formation of ferrous sulfide precipitate, providing abundant active adsorption sites for Mn species. In the solution containing all the valuable metals, Fe2+ promoted the recoveries of the valuable metals due to the higher concentration of Na2S and the formation of ferrous sulfide precipitate. / Doctor of Philosophy / The rapid development of advanced technologies has increased the demand for critical elements essential in manufacturing high-tech products. In this study, a process was developed for producing high-purity Mn, Co, and Ni products from an acid mine drainage (AMD). A product with around 30 wt.% Mn was produced. Co and Ni products with 94% and 100% purity were also obtained. However, when developing the process, it was found that a portion of the REEs is often lost to the precipitates of the dominant metal contaminant ions (Fe and Al) in the staged precipitation. It was found that the REE removal increase was realized through adsorption onto the surfaces of the ferric precipitates. In sulfide precipitation, the presence of Fe and Al in the solution can significantly influence the separation efficiency of the critical elements. The effect of Al3+ on the sulfide precipitation is due to the simultaneous hydrolysis of aluminum and sulfur ions. The reduction of the recovery of valuable metals caused by the Fe2+ is due to the form of iron sulfides.

No description available.

Many grasslands in arid and semi-arid regions are undergoing rapid changes in vegetation, including encroachment of woody plants and invasive grasses, which can alter the rates and patterns of fire and sediment transport in these landscapes. We investigated the spatial distribution of sediments at the scale of vegetated microsites for three years following a prescribed fire using a multiple rare earth element (REE) tracer-based approach in a shrub-grass transition zone in the northern Chihuahuan desert (New Mexico, USA). To this end, we applied REE tracers – holmium, europium, and ytterbium on shrub, grass, and bare microsites, respectively in March 2016. Soil samples were collected from both burned and control (not burned) sites before (March) and after (June) the annual windy season, from 2016 through 2018. Results indicate that although the horizontal mass flux (HMF) of wind-borne sediment increased approximately threefold in the first windy season following the fire, and the HMF of both plots were not significantly different after three windy seasons. Comparing REE concentrations in sediments from both plots over the three years and three annual windy seasons, we observed a post-fire shift in source and sink dynamics of sediments. The tracer analysis of wind-borne sediments indicated that the source of the HMF in the burned site was mostly derived from shrub microsites following the fire, whereas the bare microsites were the major contributors for aeolian sediment in control areas. The shift in sources and sinks, and the spatial homogenization of REEs indicate that the removal of shrub vegetation resulted in sediment redistribution to the bare microsites even three years after the prescribed fire. The findings of this study will improve our understanding of post-fire geomorphic processes at a microsite scale in a grassland ecosystem undergoing land degradation induced by shrub encroachment. / Geology

Sediment is a major source of water quality impairment in streams, rivers and lakes in the US. However, sediment fate and transport in small streams is poorly understood. Previous attempts to characterize sediment transport often insufficiently represented the physical and chemical sediment properties and lacked spatial and/or temporal resolution. Therefore, there is a need to develop better sediment tracers, for which rare earth element (REE)-labeled sediment is examined as an alternative. The objectives of this study were to: 1) assess the adsorption of REEs to natural soils and ensure their reliability as a tracer in a fluvial environment; and 2) evaluate the efficacy of utilizing REE-labeled sediment to quantify fate and transport in a second-order stream during a series of storm events. Two natural stream bank soils from Stroubles Creek in Virginia were labeled with the REEs lanthanum and ytterbium. The REEs adsorbed equally to both soils and had minimal desorption after several washes with stream water. This suggests that REEs form a dependable natural sediment tracer and sufficiently label natural soils for use in a sediment tracing study. During two storm events, two unique REE tracers were injected into Stroubles Creek. These tracers were detected at varying discharges and sediment loads in bed and suspended sediment samples up to 875 m downstream. REE tracers proved to be an ideal tracer for detecting sediment fate and transport in a small stream during a series of storm events and hold great potential for evaluating best management practices and sediment transport models. / Master of Science

Many literatures have been published recently regarding the recovery of REEs from coal-related materials, such as coal waste, acid mine drainage, and coal combustion ash. The recovery of REEs from coal waste has been investigated by the author in recent years, and it was found that after calcination at 600 ℃ for 2 h, a significant improvement in REE recovery can be achieved. In order to reveal the mechanisms of the enhanced REE recovery after calcination, coal waste samples from two different seams, i.e., Western Kentucky No. 13 and Fire Clay, were selected to investigate the modes of occurrence of REEs. Scanning electron microscopy- and transmission electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS and TEM-EDS) analyses were conducted to investigate the mineralogy of REEs in two coal waste samples. Totally, 49 and 50 REE-bearing particles were found from the SEM specimens of Western Kentucky No. 13 and Fire Clay coal waste samples, respectively. Based on the elemental composition analyses and TEM-EDS characterization, it was found that apatite, monazite, and crandallite-group minerals were the major light REE (LREE) carriers, while the heavy REEs (HREE) primarily occurred in zircon and xenotime in these two coal waste samples. Further analyzing the REE content and number of REE-bearing particles, it was confirmed that monazite, xenotime, and crandallite-group minerals were the dominant contributors to the total REE (TREE) contents in both materials. In addition to the mineralogy of REEs, the morphology of REE-bearing particles was also investigated. The SEM images suggested that the particle size of most REE-bearing particles was less than 5 μm. Moreover, not only completely liberated particles, but particles encapsulated by the host minerals present in the two coal waste samples. To identify the changes of mineralogy of REEs after recovery, the leaching solid residues of the raw and calcined coal waste samples were also characterized by SEM-EDS analysis. After REE recovery, the same REE mineralogical results were observed from the leaching residues of the raw coal waste samples. However, as for the calcined samples, the crandallite-group minerals disappeared. These results suggested that the crandallite-group minerals were decomposed into easy-to-leach forms after calcination at 600 ℃, thus leading to the improved REE recovery. Moreover, the number of REE-bearing particles (N) found from per area of the calcined leaching residue was confirmed to be larger compared to that of the raw ones. A combination analysis of these results indicated that two mechanisms of the enhanced REE recovery after calcination can be confirmed: (1) decomposing the crandallite-group minerals into more soluble species; and (2) promoting the liberation of the REE-bearing particles encapsulated in the host minerals. The thermal decomposition of crandallite-group minerals was mainly responsible for the enhanced REE recovery from coal waste. However, as a result of the complex isomorphic substitutions and association characteristics, it is difficult to collect a pure endmember of crandallite-group mineral for characterization. Therefore, florencite-(Ce) was synthesized in this study. X-ray diffraction (XRD), SEM-EDS, TEM, thermogravimetric and differential thermal analyses (TGA-DTA), and acid leaching tests were conducted on the synthesized product. The results showed that the variation in Ce leaching recovery corresponded to the phase transformation of florencite. The gradual transformation of florencite from a crystalline mineral into an amorphous phase resulted in the increases in the solubility of Ce. In addition, the thermal transformation of florencite was an independent reaction, which was not interfered by the host materials, such as kaolinite and coal waste. / Doctor of Philosophy / Coal waste has been identified as a promising alternative source of rare earth elements (REEs). This study showed that calcination can significantly improve the REE recovery from coal waste materials. Scanning electron microscopy- and transmission electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS and TEM-EDS) analyses were conducted to investigate the mineralogy of REEs in two coal waste samples. The results indicated that the REEs mainly present as apatite, zircon, monazite, xenotime, and crandallite-group minerals in the coal waste samples. However, after REE recovery, the crandallite-group minerals disappeared from the calcined coal waste samples. Therefore, it can be confirmed that the calcination treatment resulted in the solubility improvement of crandallite-group minerals in coal waste samples. In order to further investigate the crandallite-group minerals, florencite was synthesized and subjected to a series of characterizations. The results suggested that the thermal phase transformation of florencite from crystalline into amorphous state resulted in the solubility improvement.

Master of Science / Department of Geology / Matthew Totten / Oil production in Kansas has a long history with plays being found on all sides of the state. The source of Kansas’s hydrocarbons has been traditionally thought to be outside the state due to low thermal maturity and the shallow burial of potential source rocks within Kansas. This research addresses the question regarding the source of the oil in Kansas, at least within a small geographic area of roughly 146mi[superscript]2. The Spivey-Grabs-Basil Field has been one of the more successful fields within the state of Kansas since the 1960’s. This field is compartmentalized and offers a natural laboratory in which to conduct the field’s first formal oil-source rock correlation since oils are locked into place. While the main focus of this research relies heavily on pyrolysis and GCMS for biomarker analysis, it also investigates the possibility of using rare earth element (REE) concentrations as a possible fingerprint of organic matter within a source bed. TOC values of the Chattanooga shale samples from the Spivey-Grabs-Basil filed range from 0.75 and 3.95 wt. %, well within productive capacity. Pyrograms show both the potential for additional production, and the likely previous expulsion of hydrocarbons. Biomarker concentration percentages between C[subscript]27, C[subscript]28, and C[subscript]29 steranes, as well as pentacyclic terpane ratios compared between crude oil from the Spivey-Grabs-Basil and the Chattanooga shale show a definite genetic relationship. REE values of the organic fraction of the Chattanooga inversely correlate with those of the crude oils, suggesting fractionation during oil generation. After comparison of results with the Woodford shale in Oklahoma, the conclusion of this study is that the Chattanooga shale which underlies the Spivey-Grabs-Basil oil field of southern Kansas is the probable source rock which generated the oil now being produced.

Master of Science / Geology / Matthew W. Totten / The most common practice of typing crude oils utilizes biomarkers to gain insight on the history of the oil. This practice only considers the organic chemistry of the oil, and does not consider the trace element concentrations within the oil. Rare earth element and other trace element concentrations in crude oil might provide further insight into the oil’s source and origin. This study analyzed REE and other trace metal concentrations of crude oil in the Spivey-Grabs field of south-central Kansas through analysis by ICP-MS and ICP-AES that, coupled with visual physical characteristics of oil and FT-IR analysis, could explain the reported “compartmentalization” of the field and provide insight on the origin of the oils. Analysis of physical characteristics of the crude oils suggested the presence of two types of oil, of differing viscosities, in the field. FT-IR confirmed the presence of these two oil types based on functional groups present in the oils. The existence of a high viscosity oil could potentially explain the compartmentalization behavior in the field. PAAS-normalized REE distribution patterns showed a general LREE enrichment, a positive cerium and negative europium anomaly, and a MREE and HREE depletion, but higher viscosity oils showed additional MREE and HREE enrichment. K/Rb values ranged from 2,864 to 44,118, with oils from mixed-viscosity wells having lower ratios overall. K/Rb values of Spivey-Grabs crude oils more closely resembled those of the Lansing-Kansas City formation than the K/Rb values of the Woodford shale and Mississippian formation of the Anadarko basin. Comparing the rare earth element distribution patterns and K/Rb values from this study to those of the Woodford shale suggests the Spivey-Grabs oil originated from a local source and not from the Woodford shale.

Rare earth elements consist of 15 lanthanides, Y and Sc. They are currently very important materials in many industrial branches (metalurgy, pollishing). One of these options is the usage as the compound of phosphors in electronic devices (television and computer displays. Because of their manufacturing cost, options of recovery from waste electrical and electronic equipment (WEEE) are investigated. This thesis deals with compoud elements of phosphors from displays of type CRT (cathode ray tube) and plasma TV. The 37 samples of phosphors from different displays were taken and processed for study of the compoud elements. Phosphors were separated to 4 subgroups in accordance with the corresponding type of displays: black-and-white CRT television displays (CRT_CB), color CRT television displays (TV_B), color PC displays (PC_B) and monochromatic PC displays (PC_M). The study was carry out by multiple features analysis that combined the inductively coupled plasma mass spectrometry (ICP-MS), the inductively coupled plasma optical emission spectrometry (ICP-OES), the resistance furnace with infrared detector (RF-IF) and the atomic absorption spectrometry (AAS). Based on the results of this analysis, main elements and potentionally hazardous elements of phosphors subgroup were defined. Concentration of rare...

Ces travaux de thèse portent sur la synthèse de nouveaux polymères hydrosolubles fonctionnalisés à des fins de complexation des lanthanides et/ou des actinides contenus dans des solutions de dissolution de minerai ou de recyclage.La synthèse d'un nouveau monomère fonctionnalisé par un motif carbamoylméthylphosphonate (cmp) nommé CPAAm6C a été réalisée. L'homopolymérisation par voie radicalaire conventionnelle de ce monomère a ensuite conduit à un matériau à la fois thermosensible et complexant. La présence d'une basse température critique de solution (ou LCST, généralement approximée avec la température de point de trouble) pourrait être valorisée dans le développement d'un procédé de séparation consistant dans un premier temps à complexer les cations en solution aqueuse (température inférieure à la LCST) puis à séparer les complexes polymères/cations formés à l'aide d'une étape de microfiltration (température supérieure à la LCST).Par hydrolyse de la fonction cmp, des polymères porteurs de fonctions acide carbamoylméthylphosphonique ont par ailleurs été préparés et caractérisés : le mhP(CPAAm6C) (monoacide) et hPCPAAm6C (diacide). L'étude de la sorption du gadolinium (lanthanide cible) sur les polymères fonctionnalisés P(CPAAm6C) et hP(CPAAm6C) en fonction de différentes conditions opératoires (concentration de gadolinium ou de polymère, pH, force ionique, température, composition des solutions) a permis de montrer que la sorption impliquait des mécanismes de coordination et/ou d'échange d'ions. Le caractère sélectif des polymères vis-à-vis du gadolinium, du thorium ou de l'uranium a également été mis en évidence. / The work reported in this manuscript deals with the synthesis of new functionalized water-soluble polymers with complexing properties towards lanthanides and/or actinides found in solutions of dissolution or recycling processes.The synthesis of a new functionalized monomer with a carbamoylmethylphosphonate (cmp) moiety, namely the CPAAm6C, was reported. Then, radical homopolymerisation of CPAAm6C was carried out, leading to material combining both thermosensitive and complexing properties. The presence of a lower critical solution temperature (LCST, generally approximated with the cloud point temperature) could be valorized in the development of a separation process in two steps consisting in first complexing the cations in aqueous solution (at a temperature below the cloud point) and then, in a second step, in separating the polymer/cations complexes using microfiltration (at a temperature above the cloud point).Hydrolysis of the cmp group was also considered and led to polymers bearing carbamoylmethylphosphonic acid groups: mhPCAAm6C(CPAAm6C) (monoacid) and hPCPAAm6C (diacid).The study of the sorption of gadolinium (targeted lanthanide) on P(CPAAm6C) and hP(CPAAm6C) functionalized polymers as a function of different operating conditions (concentration of lanthanide or polymer, pH, ionic strength, temperature, composition of the solution) allowed to provide information on the sorption mechanisms (coordination and ion exchange). Selectivity of the polymers toward gadolinium, thorium or uranium was also investigated.