Characterization and assessment of potential environmental risk of tailings stored in seven impoundments in the Aries river basin, Western Romania

BACKGROUND: The objective of this study was to examine the potential environmental risk of tailings resulted after precious and base metal ores processing, stored in seven impoundments located in the Aries river basin, Romania. The tailings were characterized by mineralogical and elemental composition, contamination indices, acid rock drainage generation potential and water leachability of hazardous/priority hazardous metals and ions. Multivariate statistical methods were used for data interpretation. RESULTS: Tailings were found to be highly contaminated with several hazardous/priority hazardous metals (As, Cu, Cd, Pb), and pose potential contamination risk for soil, sediments, surface and groundwater. Two out of the seven studied impoundments does not satisfy the criteria required for inert wastes, shows acid rock drainage potential and thus can contaminate the surface and groundwater. Three impoundments were found to be highly contaminated with As, Pb and Cd, two with As and other two with Cu. The tailings impoundments were grouped based on the enrichment factor, geoaccumulation index, contamination factor and contamination degree of 7 hazardous/priority hazardous metals (As, Cd, Cr, Cu, Ni, Pb, Zn) considered typical for the studied tailings. Principal component analysis showed that 47% of the elemental variability was attributable to alkaline silicate rocks, 31% to acidic S-containing minerals, 12% to carbonate minerals and 5% to biogenic elements. Leachability of metals and ions was ascribed in proportion of 61% to silicates, 11% to acidic minerals and 6% to the organic matter. A variability of 18% was attributed to leachability of biogenic elements (Na, K, Cl(-), NO(3)(-)) with no potential environmental risk. Pattern recognition by agglomerative hierarchical clustering emphasized the grouping of impoundments in agreement with their contamination degree and acid rock drainage generation potential. CONCLUSIONS: Tailings stored in the studied impoundments were found to be contaminated with some hazardous/ priority hazardous metals, fluoride and sulphate and thus presents different contamination risk for the environment. A long term monitoring program of these tailings impoundments and the expansion of the ecologization measures in the area is required

Influence of the Structure on Magnetic Properties of Calcium-Phosphate Systems Doped with Iron and Vanadium Ions

The aim of this study was to prepare and characterize the glasses made of x(Fe$_{2}$O$_{3}$∙V$_{2}$O$_{5}$)∙(100 − x)[P$_{2}$O$_{5}$∙CaO] with x ranging of 0–50%. The contribution of Fe$_{2}$O$_{3}$ and V$_{2}$O$_{5}$ amount on the structure of P$_{2}$O$_{5}$·CaO matrix was investigated. The vitreous materials were characterized by XRD (X-ray diffraction analysis), EPR (Electron Paramagnetic Resonance) spectroscopy, and magnetic susceptibility measurements. A hyperfine structure typical for isolated V4+ ions was noticed to all spectra containing low amount of V$_{2}$O$_{5}$. The XRD spectra show the amorphous nature of samples, apart x = 50%. An overlap of the EPR spectrum of a broad line without the hyperfine structure characteristic of clustered ions was observed with increasing V2O5 content. The results of magnetic susceptibility measurements explain the antiferromagnetic or ferromagnetic interactions expressed between the iron and vanadium ions in the investigated glass

Copper-releasing, borate-based glasses with antibacterial properties: synthesis and in vitro characterization

In this study, glasses within the system (60-x) B2O3⋅x ZnO⋅34CaO⋅1CuO, with x=5, 10, 15, 20, 25 mol% and with B2O3/ZnO ratios 11; 5; 3; 2; 1.4 have been synthesized and characterized in vitro. After being immersed in simulated body fluid (SBF) and saline solution, weight loss reduction and pH measurments, followed by inductively coupled plasma optical emission spectometry (ICP-OES), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were performed, in order to evaluate the changes in glass morphology. In vitro biodegradation and surface reaction were observed in all of the glasses, especially in the x=10, 15, 20 samples. SEM and XRD results revealed the presence of a hydrotalcite-like structure (double layered hydroxid) at the aqueous solution-glass surface interface, while Cu, Zn, Ca and B ions, with proangiogenic properties, were detected in the immersion fluid

Obtaining and Characterizing Alginate/k-Carrageenan Hydrogel Cross-Linked with Adipic Dihydrazide

The aim of this paper is obtaining and characterizing hydrogels based on different ratios of oxidized alginate (oA) and k-carrageenan (C), chemically cross-linked with adipic dihydrazide (adh). The alginate (A) was first oxidized with sodium metaperiodate in order to transform it into the dialdehyde derivative, a more reactive compound than alginate. A known procedure for oxidation of alginate with sodium metaperiodate in ethanol-water in order to improve alginate reactivity by transforming the hydroxyl end-groups into dialdehyde was used, preceded by a partially cleavage of the alginate chains. In the second stage, the mixture of dialdehydic derivative of oxidized alginate, k-carrageenan and glycerol subjected to reaction with adipic dihydrazide leads to a Semi-Interpenetrated Network covalently cross-linked alginate/k-carrageenan hydrogel (oACadh), based on the dihydrazone compound which is responsible for the chemical cross-linking. Pure alginate, k-carrageenan, oxidized alginate, adipic dihydrazide and the cross-linked hydrogel were characterized by: FTIR, XRD, and SEM

On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

Der erste Teil der Aktivitäten dieser Arbeit bestand in der Entwicklung einer modernen Ionenspeicher Apparatur zur Untersuchung chemischer Prozesse mit atomarem Wasserstoff. Die Integration eines differentiell gepumpten Radikalenstrahls in eine vorhandene temperaturvariable 22-Pol Speicherapparatur erforderte größere Änderungen an dieser. Da astrophysikalische Fragestellungen im Vordergrund standen, führt die Einleitung zunächst in das Gebiet der Astrophysik und -chemie ein. Die Grundlagen der Ionenspeicherung in temperaturvariablen Hf-Speichern sind ausführlich in der Literatur dokumentiert. Daher ist die Beschreibung der Apparatur (Kapitel 2) relativ kurz gehalten. Viel Mühe wurde in die Entwicklung einer intensiven und stabilen Quelle für Wasserstoffatome aufgewandt, deren kinetische Energie variiert werden kann. Das Kapitel 3 beschreibt dieses Modul in vielen Details, wobei der Einsatz von magnetischen Hexapolen zum Führen der Atome und die chemische Behandlung der Oberflächen zur Reduzierung der H-H Rekombination einen wesentlichen Platz einnimmt. Durch die außergewöhnliche Empfindlichkeit der Speichertechnik kann das neue Instrument zur Untersuchung von vielen Reaktionen eingesetzt werden, die von astrochemischer und fundamentaler Bedeutung sind. Die Ergebnisse dieser Arbeit sind im Kapitel 4 zusammengestellt, einige Reprints und Entwürfe von Publikationen findet man im Anhang. Die Reaktionen von CO2+ mit Wasserstoffatomen und -molekülen erwiesen sich als sehr geeignet, um in situ H and H2 Dichten über den gesamten Temperaturbereich der Apparatur zu bestimmen (10 K - 300 K). Zum ersten mal wurden Reaktionen von H- and D-Atomen mit den Kohlenwasserstoffionen CH+, CH2+, and CH4+ bei Temperaturen des interstellaren Raums untersucht. Ein sehr interessantes, noch nicht ganz verstandenes Stoßsystem ist die Wechselwirkung von protoniertem Methan mit H-Atomen. Im Ausblick der Arbeit werden einige Ideen aufgezeigt, wie man das Instrument verbessern kann, und es werden einige Reaktionen erwähnt, die man als nächste untersuchen könnte. Diese Dissertation ist einen Beitrag zum Projekt 5 der Forschergruppe Laboratory Astrophysics: Structure, Dynamics and Properties of Molecules and Grains in Space, die von der DFG im Zeitraum von 2000 bis 2006 unterstützt wurde.The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22-pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4, some reprints and drafts are reproduced in the appendix. Reactions of CO2+ with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H2 densities over the full temperature range of the apparatus (10 K - 300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH+, CH2+, and CH4+ have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. This thesis is a contribution to the project 5 of the research unit Laboratory Astrophysics: Structure, Dynamics and Properties of Molecules and Grains in Space which has been supported by the DFG from 2000 to 2006

On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

Der erste Teil der Aktivitäten dieser Arbeit bestand in der Entwicklung einer modernen Ionenspeicher Apparatur zur Untersuchung chemischer Prozesse mit atomarem Wasserstoff. Die Integration eines differentiell gepumpten Radikalenstrahls in eine vorhandene temperaturvariable 22-Pol Speicherapparatur erforderte größere Änderungen an dieser. Da astrophysikalische Fragestellungen im Vordergrund standen, führt die Einleitung zunächst in das Gebiet der Astrophysik und -chemie ein. Die Grundlagen der Ionenspeicherung in temperaturvariablen Hf-Speichern sind ausführlich in der Literatur dokumentiert. Daher ist die Beschreibung der Apparatur (Kapitel 2) relativ kurz gehalten. Viel Mühe wurde in die Entwicklung einer intensiven und stabilen Quelle für Wasserstoffatome aufgewandt, deren kinetische Energie variiert werden kann. Das Kapitel 3 beschreibt dieses Modul in vielen Details, wobei der Einsatz von magnetischen Hexapolen zum Führen der Atome und die chemische Behandlung der Oberflächen zur Reduzierung der H-H Rekombination einen wesentlichen Platz einnimmt. Durch die außergewöhnliche Empfindlichkeit der Speichertechnik kann das neue Instrument zur Untersuchung von vielen Reaktionen eingesetzt werden, die von astrochemischer und fundamentaler Bedeutung sind. Die Ergebnisse dieser Arbeit sind im Kapitel 4 zusammengestellt, einige Reprints und Entwürfe von Publikationen findet man im Anhang. Die Reaktionen von CO2+ mit Wasserstoffatomen und -molekülen erwiesen sich als sehr geeignet, um in situ H and H2 Dichten über den gesamten Temperaturbereich der Apparatur zu bestimmen (10 K - 300 K). Zum ersten mal wurden Reaktionen von H- and D-Atomen mit den Kohlenwasserstoffionen CH+, CH2+, and CH4+ bei Temperaturen des interstellaren Raums untersucht. Ein sehr interessantes, noch nicht ganz verstandenes Stoßsystem ist die Wechselwirkung von protoniertem Methan mit H-Atomen. Im Ausblick der Arbeit werden einige Ideen aufgezeigt, wie man das Instrument verbessern kann, und es werden einige Reaktionen erwähnt, die man als nächste untersuchen könnte. Diese Dissertation ist einen Beitrag zum Projekt 5 der Forschergruppe Laboratory Astrophysics: Structure, Dynamics and Properties of Molecules and Grains in Space, die von der DFG im Zeitraum von 2000 bis 2006 unterstützt wurde.The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22-pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4, some reprints and drafts are reproduced in the appendix. Reactions of CO2+ with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H2 densities over the full temperature range of the apparatus (10 K - 300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH+, CH2+, and CH4+ have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. This thesis is a contribution to the project 5 of the research unit Laboratory Astrophysics: Structure, Dynamics and Properties of Molecules and Grains in Space which has been supported by the DFG from 2000 to 2006

Exploring the Polymorphism of Drostanolone Propionate

2α-Methyl-4,5α-dihydrotestosterone 17β-propionate, known as drostanolone propionate or masteron, is a synthetic anabolic-androgenic steroid derived from dihydrotestosterone. The crystal structures of two polymorphs of drostanolone propionate have been determined by single crystal X-ray diffraction and both crystallizes in the monoclinic crystal system. One is belonging to the P21 space group, Z = 2, and has one molecule in the asymmetric unit while the second belongs to the I2 space group, Z = 4, and contains two molecules in the asymmetric unit. Another polymorph has been investigated by an X-ray powder diffraction method and solved by Parallel tempering/Monte Carlo technique and refined with the Rietveld method. This polymorph crystallizes in the orthorhombic P212121 space group, Z = 4 having one molecule in the asymmetric unit. The structural configuration analysis shows that the A, B, and C steroid rings exist as chair geometry, while ring D adopts a C13 distorted envelope configuration in all structures. For all polymorphs, the lattice energy has been computed by CLP (Coulomb-London-Pauli), and tight-binding density functional theory methods. Local electron correlation methods were used to estimate the role of electron correlation in the magnitude of the dimer energies. The nature of the intermolecular interactions has been analyzed by the SAPT0 energy decomposition methods as well as by Hirshfeld surfaces

N-Butyl-4-butylimino-2-methylpentan-2-aminium (E)-quercetinate

The title salt, C14H31N2+·C15H9O7−, was obtained in the reaction of quercetin with n-butylamine in a mixture of acetone and hexane. The crystal structure determination shows that the quercetin donates one of its phenol H atoms to the N-butyl-4-butylimino-2-methylpentan-2-amine molecule. The crystal structure of the salt is stabilized by intramolecular (N—H...N for the cation and O—H...O for the anion) and intermolecular hydrogen bonding (N—H...O between cation–anion pairs and O—H...O between anions). Quercetin molecules form dimers connected into a two-dimensional network. The dihedral angle between the quercetin ring systems is 19.61 (8)°

Structural Insights and Intermolecular Energy for Some Medium and Long-Chain Testosterone Esters

Testosterone (17β-Hydroxyandrost-4-en-3-one) is the primary male anabolic-androgenic steroid. The crystal structures of two medium and two long esterified forms of testosterone, including enanthate, cypionate, decanoate and undecanoate, were determined by X-ray single crystal diffraction. The samples were also characterized by powder X-ray diffraction, FT-IR spectroscopy and thermal analysis (DTA, TG). Crystal packings and supramolecular features were described. The analysis of structural features was accomplished by computational methods in terms of the type of intermolecular interactions, crystal energies and Hirshfeld surfaces analysis. From a pharmaceutical point of view, the solubility of compounds was investigated