Tesi sul tema "Arsenic and Antimony"
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1
Perry, Meghan Rose. "Arsenic, antimony and visceral leishmaniasis". Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/14edf50b-4943-4ec8-8556-8aaecf3a9f49.
Abstract (sommario):
In Bihar state, India, the cure rate of antimonial compounds in the treatment of visceral leishmaniasis (VL) has declined from over 85% to less than 50%. This has been attributed to prolonged, widespread misuse of antimonials within the Indian private healthcare system. An alternative resistance hypothesis is that exposure to arsenic in drinking water in this region has resulted in antimony-resistant Leishmania parasites. Leishmania donovani were serially passaged in mice exposed to environmentally-relevant levels of arsenic in drinking water. Arsenic accumulation in organs of these mice was proportional to exposure. After five passages, isolated parasites were refractory to SbV in drug sensitivity assays. Treatment of infected mice with SbV confirmed that these parasites retained resistance in vivo, supporting this hypothesis. A retrospective field study on a cohort of antimony treated VL patients was performed in an arsenic contaminated area of Bihar to evaluate the presence of an increased risk of treatment failure and death in those exposed to arsenic. It demonstrated a significant increased risk of death from VL in arsenic exposed patients but did not indicate a significant relationship between arsenic exposure and antimonial treatment failure. Collectively these data suggest that it is biochemically possible that arsenic contamination may have contributed to the development of antimonial resistance in Bihar although issues of underpower and the retrospective nature of our epidemiological study made it difficult to conclusively demonstrate this. Further research in to the relationships between arsenic exposure and antimonial treatment failure and death in the leishmaniases is warranted.
2
Andrewes, Paul. "Arsenic and antimony biomethylation by Scopulariopsis brevicaulis". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0009/NQ56494.pdf.
3
Koch, Iris. "Arsenic and antimony species in the terrestrial environment". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ34566.pdf.
4
Shaikh, Taimur A. "NEW DEVELOPMENTS IN CYCLIZED ARSENIC AND ANTIMONY THIOLATES". UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/494.
Abstract (sommario):
There is a continued interest in the properties of arsenic thiolate compounds for both industrial and biological uses. Recent discoveries in the medicinal properties of such compounds have resulted in a sustained need for the synthesis of new dithiarsolane compounds for research as anti-leukemic compounds. Close analogues of the 2-halo arsenic dithiolates, namely those with an arsenic-carbon bond instead of an arsenic-halide bond, have recently been shown to have some efficacy towards leukemia cells. Based on the hydrolytic character and the active role of glutathione with arsenic in vivo, the compounds reported here may also have such activity. Arsenic compounds have demonstrated biological activity in the literature, thus the hypothesis of this thesis is cyclized arsenic thiolates can be synthesized with the appropriate characteristics as to be potentially useful medicinal agents as well as provide new structural and reaction information. A series of arsenic and antimony di- and trithiolates has been synthesized and characterized. Those compounds include 2-chloro-1,3,2-dithiarsolane, 2-bromo- 1,3,2-dithiarsolane, 2-iodo-1,3,2-dithiarsolane, 2-chloro-1,3,2-dithiarsenane, 2-bromo- 1,3,2-dithiarsenane, 2-iodo-1,3,2-dithiarsenane, 3-chloro-4H,7H-5,6-benz-1,3,2- dithiarsepine, 2-chloro-benzo-1,3,2-dithiarsole, 1,2-bis-dithiarsolan-2-ylmercapto-ethane, tris-(pentafluorophenylthio)-arsen, bis(2-(1,3,2-benzodithiarsol-2ylsulfanyl)- benzenesulfide), 2-chloro-benzo-1,3,2-dithiastibole, and bis(2-(1,3,2-benzodithistibol)- 1,2-benzenedithiol. Elucidation of the pH characteristics of arsenic dithiolates within the human toxicity reaction pathway is an area of interest. It has been shown that the aqueous arsenic dithiolate stability depends on the size of the ring. 2-Chloro-1,3,2-dithiarsolane has been shown to be somewhat stable at both low and high pH as well as neutral pH. 1,2-bis- Dithiarsolan-2-ylmercapto-ethane is completely stable in a neutral aqueous solution. Glutathione does not permanently bind to arsenic even in overwhelming excess. In particular, these fully characterized compounds determine how reactive the AsS and AsCl linkages are under environmental and biological conditions, and provide a source of new reagents to examine in medical applications. Future applications may include the incorporation of the reported compounds in filtration and remediation technologies with further modification.
5
Collins, Helen. "Halide transfer reactions of arsenic, antimony and bismuth". Thesis, University of Warwick, 1991. http://wrap.warwick.ac.uk/108064/.
Abstract (sommario):
The study of Group 15 (As, Sb, Bi) halide exchange reactions. The Lewis acidity of SbCls was displayed using various metal halides. Treatment of the metal halides MCln (n=2, M=Mg, Sn; n=3, M=Sc, Y, La, Ti, In; n=4, M=Ti, Sn) with SbCls in MeCN provided antimonate(V) salts of the type [MCln-lL7-n][SbCl6] characterised by ^lgb nmr, electronic and infra-red spectroscopy and accompanying microanalytical data. Depending upon the stoichiometry of the reactants used the antimonate salts have been formulated as [MCln-xL6-(n-x)]x+[SbCl6]x‘ (where n=2, 3, 4; x=l, 2, 3). The formation of mono-, di- and tricationic metal species has been effected by single and multiple halide abstraction, the resultant formation of 1:1. 1:2 and 1:3 electrolytes in MeCN has been confirmed by conductivity studies. The Lewis acidity and basicity of BiCl3 was illustrated by treatment of MCln (n=2, M=Mg; n=5, M=Sb respectively) with BiCl3 in MeCN. Reaction with n=2, M=Mg gave bismuthate(III) salts of the type [Mg(MeCN)6)mlBi4Cli2+2m]2m'- "1=2, 3, depending upon the stoichiometry of the reactants used. The crystal structure of the product m=2 in MeCN resulted in the hexa-coordinated magnesium [Mg(MeCN)$J2+ dication and the novel tetranuclear bismuth(III) chloro anion [Bi4Cll6l4". which contains three different types of chlorine atoms; ten terminal, four an(j two Where m=3 gave a tetranuclear anion [18- Further variation of the stoichiometry of the MgCl2/BiCl3 system did not give any other products. Conductivity measurements confirm the products as 2:1 and 3:1 electrolytes in DMF. However reaction of BiCl3 with n=3, m=Ti, V, Cr, Fe; n=4, M=Ti, Sn led to the neutral [MCI3L3] and [MCI4L2] adducts. The limited Lewis acidity of SbCl3 towards MCln was displayed by reaction of MCln (n=3, M=Ti, Fc, In, Bi; n=4, M=Ti, Sn) with SbCl3 in MeCN which gave the neutral MCInLx (L=MeCN, x=2, 3) adducts. Reaction with n=5, M=Sb provided SbCl3-SbCl5.4MeCN. The oxidation of As(III) to As(V) using chlorine and reaction with MCln (n=4, M=Ti, Sn, n=2, M=Zn) gave the MClnLx adducts. Reaction with n=2, M=Mg and MC4NCI gave [Mg(MeCN)6][AsCl6] and [Me4Nl[AsCl6l- [TiCl3(MeCN)3HSbCl6) and [TiCl2(MeCN)4][SbCl6)2 have been shown to behave as reactive centres for ligand and/or chloride exchange reactions with neutral, L' and anionic, L" ligands (L'=PPh3; L"=C1‘, Br*). Reaction with L’=PPh3 gave [TiCl3(PPh3)][SbCl6l and with L'=C|- gave TiCl4L2- Reaction of T1CI4 with MgCl2 in MeCN gave the ternary complex MgCl2.TiCl4.6MeCN.
6
Junk, Margrit. "Material properties of copper alloys containing arsenic, antimony, and bismuth". Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2009. http://nbn-resolving.de/urn:nbn:de:swb:105-1299566.
Abstract (sommario):
This work deals with Early Bronze Age ingot torques, their composition, and material properties. The aim was to decide whether and how a choice of materials by composition or properties was possible during the Early Bronze Age. Early Bronze Age ingot torques were analysed and artefacts from several hoard finds and working stages were investigated metallographically. On the basis of these data the production technology was reconstructed. For the determination of mechanical and technological properties, reference alloys were produced and investigated. The production process was simulated by forging experiments. The investigations revealed that ingot torques were produced by a standardised technology, independent of their composition. The results of the material testing show that it is possible to distinguish the composition of the Early Bronze Age alloys by their mechanical and technological properties.
7
Francis, M. D. "Studies of low co-ordinate phosphorus, arsenic and antimony compounds". Thesis, Swansea University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637005.
Abstract (sommario):
The work described in this thesis revolves around one main theme: the chemistry of the group 15 elements phosphorus, arsenic and antimony in low co-ordinate states. The work is divided into seven chapters. Chapter one is a general introduction and briefly reviews the basic properties of the group 15 elements. It also introduces the double bond rule, the concept of low co-ordination and how low co-ordinate main group species can be stabilised using bulky substituents and/or delocalisation of electrons. Chapter two describes the synthesis and characterisation of a group 15 substituted cyclopentadienyl system, namely the 1,4,2-diphosphastibolyl anion [1,4,2-P2SbC2But2]- which contains two di-co-ordinate phosphorus centres and a two co-ordinate antimony centre. Chapter three describes the preparation and characterisation of a range of transition metal complexes derived from the diphosphastibolyl ring anion in which it exhibits η5:η1 co-ordination behaviour. The theme of Chapter four is the synthesis and characterisation of main group compounds derived from the diphosphastibolyl anion including a polyhetero-plumbocene and-stannocene. Chapter 5 moves away from the area of substituted cyclopentadienyl systems and into the field of group 15 heteroalkynes. The first part describes the synthesis and characterisation of a compound formulated as a rare example of a σ-phosphaalkyne complex in which the phosphaalkyne bonds to a ruthenium (0) centre via its lone pair of electrons. The second part discusses the coupling reaction of phosphaalkynes with an alkyne at a dirhodium centre. The co-ordination properties of the coupled products are investigated. The latter part of Chapter 5 describes the synthesis and characterisation of compounds derived from the metal mediated coupling reactions of the arsaalkyne, As≈CMes*. These compounds are only the second and third reported to be derived from the direct reaction of an arsaalkyne. Chapter 6 discusses the 1,2-addition reactions of phenylselenyl halides to phosphaalkynes. The factors influencing the regio- and stereochemistry of the resulting selenophosphaalkenes are considered and a possible mechanism for the process is proposed. The final chapter contains some concluding remarks on the work.
8
GaÌl, Judit M. "Biogeochemistry of arsenic and antimony : risk assessment in mining areas". Thesis, University of the West of Scotland, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430897.
9
Rouwane, Asmaa. "Mobilité de l'Arsenic (As) et l'antimoine (Sb) d'origine géogénique dans un sol hydromorphe d'une zone humide agricole". Thesis, Limoges, 2016. http://www.theses.fr/2016LIMO0103.
Abstract (sommario):
Nous avons identifié le rôle de la distribution solide et l’implication de facteurs (potentiel d’oxydoréduction, anions compétiteurs, activité biologique, matière organique (MO)) dans la mobilité de l’arsenic (As) et l’antimoine (Sb) dans un sol de zone humide (ZH) agricole. Pour cela, nous avons effectué i) un suivi de la physico–chimie de l’eau interstitielle de la ZH et ii) des incubations en batch du sol de surface de la ZH (0–20/30 cm). En parallèle, nous avons déterminé la distribution solide de As et Sb sur le sol de la ZH à différentes profondeurs (0–130 cm). Nous avons démontré que As est accumulé à la surface du sol avec une association préférentielle avec les oxyhydroxydes de Fe/Mn « amorphes » (59% de As total) en présence de taux élevés de MO. En conditions réductrices, As est fortement solubilisé (jusqu’à 20% de la teneur en As total) contrairement aux conditions oxydantes ce qui est associé i) à la dissolution des oxyhydroxydes de Fe/Mn catalysée par l’activité microbienne et ii) au changement de la spéciation inorganique de As sous forme de As(III) (espèce plus mobile que As(V)). Pour ce qui est de Sb, il est accumulé à la surface du sol avec i) une distribution plus étendues avec les phases solides (27% et 15% dans les oxyhydroxydes de Fe/Mn « amorphes » et « cristallins », 21% dans la MO et 32% dans la fraction résiduelle) et ii) une affinité directe pour la MO contrairement à As. La mobilisation de Sb est favorisée en conditions oxydantes (jusqu'à 5 μg.L–1) en présence de MO dissoute dans l’eau interstitielle et est limitée en conditions réductrices (<3%) (0,2 μg.L–1 dans l’eau interstitielle et 1,5 μg.L–1 dans les batch). Cette mobilité en conditions réductrices est attribuée i) à la dissolution réductrice des oxyhydroxydes de Fe/ Mn catalysée par l’activité microbienne réductrice du sol et ii) au possible changement d’état d’oxydation de Sb sous forme de Sb(III) (espèce moins mobile que Sb(V)). En conditions réductrices, l’apport de 50 mg.L–1 de nitrates et de 20 mg.L–1 de phosphates au sol a engendré une mobilisation plus importante de As et Sb (d’un facteur 2,3 et 1,6, respectivement) qui est attribuée à une possible amplification de la respiration microbienne du sol causant une production plus importante en ions hydrogénocarbonates qui en plus des ions phosphates favoriserait la mobilisation de As et Sb par des effets de compétitionIn this study, we evaluated the effect of i) solid-phase distribution and ii) biophysico–chemical factors (redox potential (Eh), competing anions, microbial activity, organic matter (OM)) on the mobility of arsenic (As) and antimony (Sb) in an agricultural wetland soil. For that, we first performed a physico–chemical monitoring of wetland porewater (field scale) then we conducted controlled batch incubations of the wetland soil (0–20/30 cm) (batch scale). The solid–phase distribution of As and Sb in wetland soil was also performed at different soil depths (0–130 cm). We showed that the highest As content was found in the upper soil layers (0–40 cm) with a preferential association to “amorphous” oxyhydroxydes (59% of total As) in presence of high levels of OM. Under reducing conditions, As was highly solubilized at both field and batch scale (up to 20% of the total As content) which was induced by i) the dissolution of Fe/Mn oxyhydroxides enhanced by soil microbial activity and ii) As(V) reduction into As(III) (very mobile specie). On the other hand, Sb mobilization was enhanced under oxidizing conditions at field scale (up to 5 μg.L–1) with the concomitant occurrence of dissolved OM (up to 93 mg.L–1) and was rather limited under reducing conditions (<3% of the total Sb content; 0.2 μg.L–1 at field scale and up to 1.5 μg.L–1 at batch scale). The mobility behavior of Sb was attributed to i) the dissolution of Fe/Mn oxyhydroxides catalyzed by microbial activity, ii) the possible occurrence of Sb in its less mobile form (Sb(III)) under reducing conditions and iii) probable DOM–induced mobilization under oxidizing conditions. Under reducing conditions, the addition of nitrate (50 mg.L–1) and phosphate (20 mg.L–1) to wetland soil, enhanced As and Sb mobilization by factors of 2.3 and 1.6 which was suggested to be caused by the combined competing effect of phosphate and hydrogenocarbonate ions; the latter one resulting from a possible enhanced microbial activity
10
Akagi, Susumu 1954. "Thermochemical nature of arsenic, antimony and bismuth in copper smelting matte". Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276743.
Abstract (sommario):
The equilibrium distribution measurements of As, Sb and Bi between molten copper and white metal and molten copper and matte were conducted to evaluate the activity coefficients of these impurity elements in copper smelting matte. The experimental results were analyzed through comparison and reconciliation with data in the literature. The following equations, based on a liquid standard state, were obtained for ᵞAs, ᵞSb and ᵞBi in white metal coexisting with copper phase at 1,150-1,200°C. Ln ᵞAs = -2.49 + 0.186 NAs; Ln ᵞSb = -1.23 + 23.5 NSb; Ln ᵞBi = 3.01 + 14.0 NBi where Ni represents the mole fraction of the element Bi in white metal. Analysis of the data demonstrated that a major factor in removing As, Sb and Bi in matte during smelting involves careful control of the sulfur pressure, ie. matte's sulfur content, the optimum matte composition's being those that approach the Cu₂S-FeS pseudo binary.
11
Cangelosi, Virginia May 1982. "Supramolecular coordination chemistry of phosphorus, arsenic, antimony, and bismuth with organothiolates". Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/11301.
Abstract (sommario):
xxiv, 203 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.The ever-expanding field of supramolecular chemistry has recently incorporated use of the main group ions. This dissertation presents a supramolecular approach to the coordination chemistry of the Group 15 elements, with a special emphasis on arsenic (As). Arsenic is ubiquitous in our environment, contaminates the drinking water of large human populations, and is a worldwide health concern. Arsenic's legendary toxicity is thought to be due to its thiophilicity and the stability of arsenic-thiolate bonds within proteins. Chapter I is a review of the current literature on the kinetics, thermodynamics, and supramolecular chemistry of the As(III)-thiolate bond and reveals that the stability and lability of the bond make it well-suited for supramolecular chemistry. The remainder of the dissertation explains our supramolecular design strategies for the As(III) ion with thiolate ligands, then expands the approach to the Group 15 elements phosphorus, antimony, and bismuth. Chapter II presents an approach to controlling diastereoselectivity in the self-assembly of supramolecular As 2 L 2 Cl 2 macrocycles using intramolecular steric interactions. Chapter III expands upon this approach by using intermolecular steric interactions to control diastereoselectivity and dimer formation of As 2 L 2 Cl 2 macrocycles. Chapter IV gives insight into the self-assembly of these As 2 L 2 Cl 2 macrocycles by identifying several reaction intermediates and kinetic mistakes that form during the course of the reaction. In Chapter V the application of our design strategy to the heavier Group 15 elements of antimony and bismuth is shown through the presentation of E 2 L 3 cryptands (E = As, Sb, Bi). Additionally, a Group 15 "transmetallation" reaction is explained which allows, for the first time, the preparation of the elusive P 2 L 3 cryptand. Chapter VI further examines the transmetallation reaction, the solution isomerism of the E 2 L 3 cryptands, and presents three heterometallic EE'L 3 cryptands. Finally, Chapter VII briefly concludes this dissertation and provides some potential future directions for the project. This dissertation includes co-authored material and previously published results.
Committee in charge: James Hutchison, Chairperson, Chemistry; Darren Johnson, Member, Chemistry; Catherine Page, Member, Chemistry; Michael Haley, Member, Chemistry; Scott Bridgham, Outside Member, Biology
12
Yersel, Müşerref Eroğlu Ahmet E. thesis advisor. "Separation of trace antimony and arsenic prior to hydride generation atomic absortion spectrometric determination/". [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/kimya/T000392.pdf.
13
Campbell, Andrew Thomas. "Some aspects of the aquatic and analytical chemistry of antimony and arsenic". Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357182.
14
Flynn, H. C. "Biosensor assessment of arsenic and antimony bioavailability in mining soils and sediments". Thesis, University of Aberdeen, 2003. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU180551.
Abstract (sommario):
Mining and smelting activities are a major source of arsenic and antimony contamination in the environment. These contaminants have been neglected when such sites are investigated, hence there is a need for their environmental impacts to be assessed. An understanding of bioavailability underpins any such assessment. This measure can only be inferred from traditional chemical techniques and the use of novel bioavailability surrogate measures. This study used a suite of three lux-marked bacterial biosensors as complimentary tools to assess metalloid bioavailability and toxicity in soils contaminated by mining and smelting. This included two constitutively marked metabolic sensors which exhibit inhibition responses to toxicity, and an ars inducible biosensor which reports on metalloid bioavailability. The biosensor responses were first characterised using standard solutions, confirming that they exhibit dose dependent responses which indicate the speciation of bioavailable forms and account for contaminant interactions. The techniques were then applied to assessing a range of environmental samples from sites around the UK, and in Chile, contaminated by either historic or contemporary mining and smelting activities. The results indicated that the metabolic biosensors are powerful tools for assessing the toxicity of bioavailable contaminants while the ars inducible biosensor reports on arsenite bioavailability. The speciation of antimony in the environmental samples resulted in low bioavailable levels, and therefore it played no significant role in determining the biosensor responses. Metal co-contaminants tended to mask the effect of arsenic on the biosensor responses and cation exchange treatment proved a successful technique to mitigate this problem. This work also highlighted the impact of extraction methodology on the chemical composition of soil water and therefore the results obtained.
15
Martinez, Marino Juan. "Evaluation of gallium arsenic(x) antimony(1-x)/indium(y) aluminum(1-y) arsenicp-channel HIGFETs for complementary technologies". Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186496.
Abstract (sommario):
This work shows the viability of p-channel GaAsₓSb₁₋ₓ/In(y)Al(1-y)As HIGFETs for III-V compound-based complementary technologies to compete with silicon CMOS for specialized applications. Monte Carlo simulation was used to establish that even for the most extreme cases of alloy scattering GaAsₓSb₁₋ₓ on InP has a higher bulk hole mobility than GaAs. Process development demonstrated that H₂O:H₂O₂:H₃PO₄:L-tartaric acid-based etchant solutions provide a reliable etchant with a selectivity of approximately 2:1 of GaAsₓSb₁₋ₓ over In(y)Al(1-y)As. Process development also showed that Ti/Au was the most reliable gate metal for contact to In(y)Al(1-y)As and that care must be taken to avoid letting some common chemical solutions come into contact with GaAsₓSb₁₋ₓ. Experimental devices established that lattice-matched GaAsₓSb₁₋ₓ channel layers had low gate leakage currents, but had otherwise poor performance. However, experimental devices with strained GaSb-rich GaAsₓSb₁₋ₓ channels had the lowest recorded gate leakage current for a heterostructure FET yielding a gate turn-on voltage of -3 V and also had transconductance and current drive comparable to the best p-channel HIGFETs of any material systems to date. Finally, SPICE simulations showed that if integrated with n-channel HIGFETs with comparable gate leakage and moderate performance, modestly improved p-channel devices make possible technology with approximately half the delay time of similar CMOS circuits. Although silicon CMOS has enormous advantages over complementary HFETs in terms of robustness and yield which allow very high densities of integration, this work clearly establishes that this infant technology has the capability to challenge the more established CMOS on the basis of speed and power consumption.
16
Cai, Jie. "Identification and characterization of a chromosomal arsenic/antimony inducible operon in gram-negative bacteria". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/NQ44376.pdf.
17
Chalmers, Brian Alexander. "A synthetic, spectroscopic and structural examination of phosphorus, arsenic and antimony peri-substituted acenaphthenes". Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7061.
Abstract (sommario):
Donor–acceptor complexes have been known for over a century and enjoy a long list of applications in chemistry. In this thesis, the dative interaction between phosphorus and its two heavier congeners, arsenic and antimony, are explored. Utilising peri-substitution atoms can be forced in close proximity to one another, resulting in a repulsive (nonbonding) interaction or an attractive (bonding) interaction. Hence, peri-substitution can be used to support traditionally ephemeral species. A range of phosphorus, arsenic and antimony containing peri-substituted compounds were synthesised and characterised using multi-nuclear NMR, mass spectrometry, elemental microanalysis and single crystal X-ray diffraction. The reduction of a peri-substituted dichloroarsine, led to the formation of a primary arsine, which underwent spontaneous elimination of hydrogen gas forming the first structurally characterised cyclic arsanylidene–σ⁴–phosphorane, the formation of which is essentially thermoneutral. With no sterically demanding groups shielding the arsenic atom, the reactivity and spectroscopic characteristics of this compound were explored through reactions with selected metal complexes. Reaction of the arsanylidene–phosphorane with a limited amount of oxygen reveals arsinidene–like reactivity via the formation of cycloarsines, supporting the formulation that the bonding can be described as a Lewis base–stabilised arsinidene R₃P→AsR. A series of phosphine–stibine and phosphine–stiborane peri-substituted acenaphthenes containing all permutations of pentavalent groups –SbCl[sub]nPh[sub](4-n) as well as trivalent groups –SbCl₂, –Sb(R)Cl, and –SbPh₂ (R = Ph, Mes), were synthesised and characterised by multi-nuclear NMR, MS, microanalysis and X-ray crystallography. The bonding in these species was studied by DFT computational methods. The P–Sb dative interactions range from strongly bonding to nonbonding as the Lewis acidity of the Sb acceptor is decreased. Unexpectedly, the phosphine–stiborane complexes represent the first examples of σ⁴P→σ⁶Sb structural motif. A study of unsymmetrical bis(phosphino)acenaphthenes showed the presence of a 3c–4e interaction, supported by the short P∙∙∙P distances and the large J[sub](PP) through-space couplings. Severely strained bis(sulfides) of the unsymmetrical phosphines experience pronounced displacements of the exocyclic peri-atoms. The resulting nonbonded intramolecular P∙∙∙P distances (ca. 4.05 Å) are among the largest ever reported peri-separations, independent of the heteroatoms involved. In addition, three metal complexes with square planar, tetrahedral and octahedral geometry are reported. In all three cases, the acenaphthene backbone is distorted to a greater extent than in the free bis(phosphine) but notably less than in the bis(sulfides).
18
Seyedi, Seyed Mojtaba. "Engineered iron oxide nanoparticle-polymer composites for the removal of dissolved arsenic and antimony". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2017. https://ro.ecu.edu.au/theses/2038.
Abstract (sommario):
Dissolved metalloids, such as arsenic (As), antimony (Sb) and boron (B), are often found in contaminated surface waters or groundwater. Their removal is essential for protecting the water environment. This MEngSci research project investigated the use of magnetite (Fe3O4) nanoparticle – polymethylmethacrylate (PMMA) composites, as a reusable adsorbent toremove dissolved As andSb.
Comparative experiments were carried out to examine the effectiveness ofcommercial magnetite nanoparticles, lab synthesized nanoparticles, and the composites of synthesed Fe3O4nanoparticle-PMMA, for adsorbing As (III) and Sb (III) ions. The effects of major environmental and operating parameters (e.g. pH and adsorbent dosage) were investigated.Four cycles of adsorption-desorption experiment were conducted; the results demonstrating significant capability of the composites of removing the dissolved metalloids. In addition, the competitive adsorption of As and Sb to the composites was studied in batch experiments. It was found that the affinity of antimony to the adsorbents was generally greater than arsenic ions. A variety of analytical methods, such as X-Ray Diffraction (XRD), microwave plasma atomic emission spectrometry (MP-AES) and Malvern Zetasizer, were used to characterise the properties of the composites and analyze dissolved As and Sb concentrations. Details of the experimentalprocedures and results have been presented in this MEngSci thesis. Overall, this research validated: (a) a process to synthesize Fe3O4 nanoparticle-PMMA composites; and (b) the efficiency of using the composites to remove dissolved metalloids from contaminated water.
19
Marmor, Joy Susan. "A mud lac amp transcriptional fusion identifies a gene induced by arsenic and antimony salts /". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60502.
Abstract (sommario):
In order to identify and characterize genes whose transcription is affected by arsenic and antimony, random lacZ fusions in the E. coli chromosome were constructed using the Mud I transposable phage. One clone was isolated that contained a lacZ transcriptional fusion induced by arsenic, antimony, and their associated salts. When cells were subjected to DNA-damaging agents such as mitomycin C and sodium dichromate, a low level of induction resulted. In addition, a marked increase in arsenic sensitivity was observed in the fusion clone as compared to the parent strain presumably due to the insertional inactivation of the E. coli gene(s) by the Mu prophage. By Southern Blotting analysis of the original gene fusion, as well as genetically identical transductant, only one copy of the lacZ fusion was observed. From these results, a preliminary map of the site of insertion of the reporter gene within the arsenic/antimony responding gene has been generated. This strain should prove to be useful in the rapid detection of low bioavailable concentrations of arsenic, as well as to study the molecular mechanisms of arsenic toxicity.
20
Urbánková, Kristýna. "Multikomponentní extrakce a prekoncentrace mikrokoncentrací As, Sb, Se a Te na modifikovaný silikagel, stanovení na ICP-AES (ICP-MS) a aplikace na vzorky vod". Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-233280.
Abstract (sommario):
The determination of inorganic speciations of arsenic, antimony, selenium and tellurium in natural waters demands often separation and preconcentration. Solid phase extraction is a very effective method for these purposes. In this paper the separation and preconcentration of these microelements is realised on the basis of modified silica Separon SGX C18, SGX C8, SGX CN, SGX NH2, SGX Phenyl and strongly basic anion Exchanger SGX AX. The sorption was provided in the presence of cationic surfactants such as benzyldimethyl dodecylammonium bromide (Ajatin), benzyldimethyltetradecylammonium chloride (Zephyramine), 1-ethoxycarbonylpentadecyltrimetrhylammonium bromide (Septonex) and selected complexing agents 4-(2-pyridylazo)resorcinol (PAR), 8-hydroxyquinoline-5-sulphonic acide (8-HQS), 1,2-dihydroxybenzene (PYR), amonium 1-pyrrolidinecarbodithioate (APDC), sodium diethyldithiocarbamate (DTC) or thiourea(Thur). The interactions of the formed ion associate with the sorbent shows a complicated character which has not been cleared as yet. The previous conditioning of the sorbent plays an outstanding role. Thus, the sorption efficiency was studied in the presence and absence of surfactant and of selected organic complexing agents. Moreover, the influence of pH of the sorbed solution as well as the speed and the volume of the solution running through the sorbent and the type and volume of the eluent on the resulting sorption efficiency was evaluated. The sorption was successfully carried out from 50-1000 ml of solution which allows the 100 fold increase of the preconcentration factor and the determination of the microelements in g.l-1 instead of mg.l-1 by using the common ICP-AES. The influence of macroelements occurring in waters as well as B, Be, Bi, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sr, Ti, V and Zn in comparable concentrations involve less than 5% error. After the quantitative elution of microelements, the organic solvents were evaporated under IR lamps prior to the determination by ICP-AES and |ICP-MS. The conditions for the direct determination of arsenic, antimony, selenium and tellurium in g.l-1 with ICP-MS were also described in detail in the absence and presence of internal standards Ge and Bi. However, even in this case the preconcentration on silica in the presence of surfactant and selected organic complexants was also tested. When the sorption was followed from 500 ml a 50 fold enrichment factor is reached and the sensitivity for the microelements is improved. The direct determination and the sorption of microelements were applied on synthetic and real waters (dirinking, surface, mineral and sea waters). Instrumental and practical detection limits for various water samples were evaluated according to IUPAC. The results from 1000 ml solution of real waters after sorption on modified silica and the final determination of microelements with ICP-AES were compared with those from ICP-MS without sorption using the method of standards addition in the presence of suitable internal standards. By comparison of results for synthetic and real water samples the error of the determination of microelements was evaluated.
21
Jirak, Jason Edward. "Enhancement of minority carrier lifetime in low quality silicon by ion implantation of arsenic and antimony". [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1469707.
22
Lesley, Michael Patrick. "The fluxes and fates of arsenic, selenium, and antimony from coal fired power plants to rivers". Thesis, Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180307/unrestricted/lesley%5fmichael%5fp%5f200312%5fms.pdf.
23
Ebengue, Atega Philippe Lionel. "Vers une distinction des contributions anthropiques et naturelles dans les contaminations en arsenic et antimoine des eaux souterraines dans le cadre d’un diagnostic territorial : application au bassin cévenol, France". Electronic Thesis or Diss., IMT Mines Alès, 2022. http://www.theses.fr/2022EMAL0002.
Abstract (sommario):
Les eaux souterraines assurent une proportion importante de l’approvisionnement eneau des territoires. La surveillance des réserves et de la qualité de ces ressourcesconstitue donc un enjeu majeur, en lien avec les Objectifs de Développement Durabledes Nations Unies. En rapport avec ces objectifs, la présente thèse traite de lacaractérisation de la qualité des masses d’eau souterraines sur un territoire ayantconnu un passé minier. Elle vise le développement d‘une méthodologie permettantd'estimer les contributions respectives du fond géochimique naturel et des apportsanthropiques, à l’enrichissement en métaux et métalloïdes dans les eaux souterraines,en considérant simultanément l'hétérogénéité de la géologie, et la combinaison defacteurs géologiques, géomorphologiques, tectoniques et statistiques. Des mesures dequalité ont été effectuées pour établir l’état des lieux des concentrations en arsenic eten antimoine dans les masses d'eau souterraines délimitées par le bassin versant duGardon dans les Cévennes. Ensuite, un opérateur d'agrégation multicritères a étédéveloppé et mis en œuvre afin de produire des cartes quantitatives et qualitativespermettant de discriminer le fond géochimique naturel des apports anthropiques.Cette cartographie a permis de déterminer des foyers remarquables situés notammentsur la faille cévenole et sur lesquels une attention particulière de surveillance doit êtreportée dans le cadre de la gestion territoriale de la qualité des ressources en eau. Unatelier interactif a permis d’évaluer les différences de perception des acteurs duterritoire face à des informations sur la qualité des eaux. Il a mis en évidence lanécessité de développer des supports de restitution des informations scientifiquesadaptés afin d’aboutir à une conscience partagée des questions liées à la qualité deseaux souterraines par les différents acteurs d’un territoireGroundwater provides a significant proportion of the water supply of the territories.The monitoring of the reserves and quality of these resources is therefore a major issue,in line with the United Nations Sustainable Development Goals. In relation to theseobjectives, this thesis deals with the characterization of the quality of groundwaterbodies in a territory with a mining past. It aims at developing a methodology toestimate the respective contributions of the natural geochemical background andanthropogenic inputs to the enrichment of metals and metalloids in groundwater,considering simultaneously the heterogeneity of the geology and the combination ofgeological, geomorphological, tectonic and statistical factors. Quality measurementswere carried out to establish the state of arsenic and antimony concentrations in thegroundwater bodies delimited by the Gardon watershed in the Cevennes. Then, amulti-criteria aggregation operator was developed and implemented in order toproduce quantitative and qualitative maps allowing the discrimination of the naturalgeochemical background from the anthropic contributions mainly constituted by thepast mining activity. This mapping made it possible to determine remarkable focilocated in particular on the Cevennes fault and on which particular attention must bepaid in the context of territorial management of the quality of water resources. Aninteractive workshop allowed to evaluate the differences of perception of the actors ofthe territory in front of information on water quality. It highlighted the need to developadapted scientific information restitution supports in order to reach a sharedawareness of groundwater quality issues by the different actors of a territory
24
Junk, Margrit. "Material properties of copper alloys containing arsenic, antimony, and bismuth the material of Early Bronze Age ingot torques /". [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968751180.
25
Borges, Elisa Moura. "Metodologia para determinação de arsênio, antimônio e bismuto por espectrometria de emissão óptica com fonte de plasma acoplado indutivamente (ICPOES) e geração de hidretos aplicada à rochas /". Rio Claro : [s.n.], 2005. http://hdl.handle.net/11449/92858.
Abstract (sommario):
Orientador: Antonio José Ranalli NardyBanca: Maria Margarita Torres Moreno
Banca: Amauri Antonio Menegário
Resumo: No presente trabalho são descritas as etapas para o desenvolvimento de uma metodologia para determinação de arsênio, antimônio e bismuto em materiais geológicos, utilizando gerador de hidretos acoplado ao ICPOES, proporcionando a determinação dos elementos de interesse em baixas concentrações. O método é sensível, por isso está sujeito a interferências, como as causadas por elementos presentes na matriz. Foram realizadas otimizações nos parâmetros operacionais e analíticos do equipamento, que visaram uma melhor sensibilidade e um método eficiente de solubilização completa de amostra de rocha, que permita a determinação dos elementos de interesse em baixas concentrações. Para a etapa de validação do método foram realizados diversos ataques com adições de padrão e testes com o uso de tiouréia e iodeto de potássio com ácido ascórbico em diferentes concentrações com o objetivo de minimizar possíveis interferências presentes na matriz. Os resultados finais foram obtidos através da solubilização de materiais de referência internacionais geológicos na determinação de arsênio, bismuto e antimônio e se mostraram satisfatórios.
Abstract: In this study, the steps for the development of a methodology to the determination of arsenic, antimony and bismuth in geological materials, with the use of hydride generation and ICPOES are being described. The methodology is sensitive due to that, subject is bound to suffer interferences from matrix elements. Optimizations in operations and analyticals parameters were done in the equipment. They aimed a better sensitivite and an efficient method of complete dissolution techniques in a sample of rock, which permits the determination of the analyte in low concentrations. For the steps of methodology validation, many dissolutions were realized with the addition of standard and tests with the use of thiourea and KI and acid ascorbic in different concentrations with the objective of minimizing some interferences from matrix elements. The final results were obtained through dissolutions with international reference materials in the determination of arsenic, antimony and bismuth.
Mestre
26
Tavora, F. J. "Lithogeochemistry and surficial redistribution of arsenic, antimony, bismuth, selenium and tellurium, associated with mineral deposits in subtropical areas of Brazil". Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46760.
27
Qi, Pengfei [Verfasser], Thomas [Akademischer Betreuer] Pichler e Andrea [Akademischer Betreuer] Koschinsky. "Adsorption behavior of arsenic and antimony onto ferrihydrite under competitive conditions / Pengfei Qi. Betreuer: Thomas Pichler. Gutachter: Thomas Pichler ; Andrea Koschinsky". Bremen : Staats- und Universitätsbibliothek Bremen, 2016. http://d-nb.info/1084169118/34.
28
Bolanz, Ralph Michael [Verfasser], Juraj [Akademischer Betreuer] Majzlan, Georg [Akademischer Betreuer] Büchel e Gerhard [Akademischer Betreuer] Heide. "Arsenic and antimony in the environment : release and possible immobilization mechanisms / Ralph Michael Bolanz. Gutachter: Juraj Majzlan ; Georg Büchel ; Gerhard Heide". Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2014. http://d-nb.info/1047579081/34.
29
Besold, Johannes [Verfasser], e Britta [Akademischer Betreuer] Planer-Friedrich. "Influences of Reduced Sulfur on Arsenic and Antimony Mobility and Binding to Natural Organic Matter / Johannes Besold ; Betreuer: Britta Planer-Friedrich". Bayreuth : Universität Bayreuth, 2020. http://d-nb.info/1218596236/34.
30
Jana, Ulrike. "Etude des interactions entre la plante Arabidopsis thaliana (L.) Heynh et le ver de terre Aporrectodea caliginosa (Savigny) : application à la phytoremédiation de l'arsenic et de l'antimoine". Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00504377.
Abstract (sommario):
L'arsenic et l'antimoine bien que n'étant pas recensés parmi les polluants majeurs de l'environnement sont souvent retrouvés associés à d'autres contaminants. En France, et plus particulièrement dans la région Auvergne, de nombreux sites miniers où s'effectuait l'extraction de l'antimoine sont désormais à l'abandon. Pouvant présenter des risques pour les populations avoisinantes, leur réhabilitation est donc une mission d'intérêt public. L'idée de ce travail de doctorat est de tester l'effet d'un catalyseur : le ver de terre sur l'efficacité des processus de phytoremédiation. En tant qu'" ingénieurs du sol ", ils sont à la base des processus de pédogénèse et peuvent donc assurer la restructuration du sol. De plus, de nombreuses études ont montré leurs effets positifs sur la production de biomasse végétale. Cependant, les mécanismes moléculaires responsables de cette acroissement de production demeurent méconnus. Un système expérimental novateur, jamais utilisé en Ecologie des Sols et couplant la plante modèle Arabidopsis thaliana (L.) Heynh et Aporrectodea caliginosa (Savigny), un ver de terre endogé commun des régions tempérées, a été mis en place afin de 1) identifier les principales voies métaboliques modifiées en réponse aux vers de terre et pouvant expliquer leurs effets positifs sur la croissance et le développement des végétaux, 2) étudier la nutrition minérale en fer et en phosphate, notamment au niveau des variations d'expression des transporteurs de ces deux éléments, 3) tester ce système pour la phytoextraction de sédiments, issus d'un ancien site minier, contaminés à l'arsenic et à l'antimoine. Les résultats montrent que l'amélioration des processus de minéralisation est déterminante dans l'accroissement de la biomasse d'Arabidopsis thaliana qui se traduit aussi par une élévation des teneurs en azote dans les parties aériennes. Cependant, la présence de phytohormones, produites par des bactéries activées par leur transit dans le ver de terre semble également impliquée dans le renforcement de l'absorption d'azote. A l'échelle moléculaire, les vers entraînent une surexpression du gène HBT, impliqué dans la division cellulaire et semblent diminuer le stress oxydant puisque la quantité de transcrits SOD Cu/Zn diminue. Les résultats montrent de plus que les vers de terre augmentent de façon significative l'absorption et l'accumulation de fer, de phosphate et d'autres minéraux essentiels à la croissance du végétal. Moléculairement, l'augmentation de l'absorption des nutriments se traduit par une augmentation de la transcription de certains gènes codant des transporteurs tels que PHT1.3, qui est un transporteur de haute affinité pour le phosphate. Une augmentation de la transcription et également de l'activité de la protéine FRO2, qui est à l'origine de la chélation et de la réduction du fer a été observée. Dans les feuilles, les vers de terre induisent de manière systémique la surexpression d'un transporteur de phosphate localisé dans les chloroplastes, PHT2.1 et la surexpression de transporteurs du fer appartenant à la famille des NRAMPs, notamment NRAMP1,2 et 6. Dans le contexte d'une problématique de phytoremédiation, l'effet des vers de terre sur la capacité de phytoextraction d'Arabidopsis a été testé et, il ressort clairement de cette étude que les vers de terre permettent une meilleure absorption d'antimoine et d'arsenic. Cependant, ces deux métalloïdes tendent à rester dans les racines et ne sont que faiblement transferrés vers les parties aériennes. Cette formidable augmentation des concentrations en polluants dans les racines entraîne un retard de croissance considérable et affecte, dans une moindre mesure cependant, l'activité photosynthétique et les échanges gazeux d'Arabidopsis. Ainsi, ce travail de thèse a donc tout d'abord démontré la sensibilité aux vers de terre de la plante modèle Arabidopsis thaliana. Ce système expérimental novateur offre de nouvelles possibilités de recherches dans le domaine des études des interactions entre les vers de terre et les plantes, notamment en raison de la grande diversité de mutants d'Arabidopsis. De plus, ce travail a également permis de démontrer le rôle crucial de catalyseur que peuvent jouer les vers de terre en vue d'optimisation des processus de phytoextraction
31
McDonald, Lauren. "Wipe Sampling Methodologies to Assess Exposures to Metals in Urban Canadian Homes: 1 Cadmium, Lead, Yttrium 2 Antimony, Arsenic, Chromium, Copper, Nickel". Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28588.
Abstract (sommario):
Wipe sampling is a means of monitoring exposures to contaminants which has been used extensively for assessment of lead (Pb) in housedust in the U.S. This thesis reports the first baseline wipe dataset for urban Canadian homes, for Pb and other metal(loid)s including: arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and antimony (Sb). The literature review covers sampling methods, health effects, and sources. The digestion procedure ASTM 1644 is the accepted HNO3 hotplate protocol for determination of Pb in wipes. However in this study, HF was added to enhance extraction efficiencies for a wide range of elements. The first paper identifies baseline and elevated subpopulations for Cd and Pb using normality plots, and investigates the use of yttrium(Y) as a soil tracer. The second paper investigates application of the wipe methodology for monitoring As, Cr, Cu, Ni, Sb, and Zn. This is the first multi-element wipe sampling dataset in the literature, and will assist risk assessors and risk managers in providing guidance to Canadians about ways to reduce exposures to metals.
32
Borges, Elisa Moura [UNESP]. "Metodologia para determinação de arsênio, antimônio e bismuto por espectrometria de emissão óptica com fonte de plasma acoplado indutivamente (ICPOES) e geração de hidretos aplicada à rochas". Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/92858.
Abstract (sommario):
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borges_em_me_rcla.pdf: 583445 bytes, checksum: a94bcee1df858747cf63f7c61d62429e (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
No presente trabalho são descritas as etapas para o desenvolvimento de uma metodologia para determinação de arsênio, antimônio e bismuto em materiais geológicos, utilizando gerador de hidretos acoplado ao ICPOES, proporcionando a determinação dos elementos de interesse em baixas concentrações. O método é sensível, por isso está sujeito a interferências, como as causadas por elementos presentes na matriz. Foram realizadas otimizações nos parâmetros operacionais e analíticos do equipamento, que visaram uma melhor sensibilidade e um método eficiente de solubilização completa de amostra de rocha, que permita a determinação dos elementos de interesse em baixas concentrações. Para a etapa de validação do método foram realizados diversos ataques com adições de padrão e testes com o uso de tiouréia e iodeto de potássio com ácido ascórbico em diferentes concentrações com o objetivo de minimizar possíveis interferências presentes na matriz. Os resultados finais foram obtidos através da solubilização de materiais de referência internacionais geológicos na determinação de arsênio, bismuto e antimônio e se mostraram satisfatórios.
In this study, the steps for the development of a methodology to the determination of arsenic, antimony and bismuth in geological materials, with the use of hydride generation and ICPOES are being described. The methodology is sensitive due to that, subject is bound to suffer interferences from matrix elements. Optimizations in operations and analyticals parameters were done in the equipment. They aimed a better sensitivite and an efficient method of complete dissolution techniques in a sample of rock, which permits the determination of the analyte in low concentrations. For the steps of methodology validation, many dissolutions were realized with the addition of standard and tests with the use of thiourea and KI and acid ascorbic in different concentrations with the objective of minimizing some interferences from matrix elements. The final results were obtained through dissolutions with international reference materials in the determination of arsenic, antimony and bismuth.
33
Furdíková, Zuzana. "Studium generování, záchytu a atomizace těkavých hydridů pro metody atomové spektrometrie". Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-233290.
Abstract (sommario):
Interference effects of co-generated hydrides of arsenic, antimony, bismuth and selenium on trapping behavior of selenium or antimony hydrides (analytes) within iridium modified, transversely heated graphite tube atomizer (THGA) was investigated. A twin-channel hydride generation system was used for independent separate generation and introduction of analyte and interferent hydrides, i.e. in simultaneous and/or sequential analyte-interferent and interferent-analyte mode of operation. Influence of the analyte and modifier mass, interferent amount, trapping temperature and composition of the gaseous phase was studied. A simple approach for elimination of mutual interference effects by modification of the gaseous phase with oxygen in substoichiometric ratio to chemically generated hydrogen is proposed and suppression of these interference effects is demonstrated. A hypothesis on mechanism of trapping and mutual interference effects is drawn.
34
Bott, Raymond C. "The Synthesis and Characterisation of Group 15 Coordination Complexes involving a-Hydroxy Carboxylic Acid Ligands". Thesis, Queensland University of Technology, 1993. https://eprints.qut.edu.au/226578/1/T%28S%29%2032_Bott_1993.pdf.
Abstract (sommario):
This thesis investigates the chemistry of the group 15 elements, arsenic(III), antimony(III), and bismuth(III) together with the a-hydroxy carboxylic acids, (2R,3R)-( + )-tartaric acid and citric acid in the formation of stable coordination complexes. Arsenic and antimony form 1:1 dimeric cage anions [Mz(tartrate)z]2-which are subsequently charge stabilised through monovalent cations. The coordination about the arsenic and antimony is pseudo trigonal bipyramidal because of a stereochemically active lone pair of electrons. However, the metallic bismuth member does not form the dimeric cages nor does it display a stereochemically pair of electrons. Instead, it exhibits both eight- and nine-coordinate geometry about bismuth and forms simple polymeric chains. The bismuth stereochemistry is typically mono-face-capped-square arfriprismatic and tri-face-capped-trigonal prismatic. The ionic radius of the monovalent counter metal ions is found to be an important factor in the stabilisation and formation of these complexes. This is shown in the structural similarlity of the silver(I) and sodium hydrogen ( + )-tartrates reported in this work (ionic radius; 1.15 - 1.18A ) and in the isomorphous Groth hydrogen )-tartrate series (ammonium, potassium, rubidium, caesium, and thallium: ionic radius; 1.46 - 1.67 A). The infrared spectra of these complexes and the arsenic(III)
( + )-tartrate complexes also show this through a decrease in frequency of the asymmetric carbonyl vibrational bands. The infrared spectra also indicate the effect that different metals and combinations of metals have on the carbonyl groups through the splitting or suppression of splitting of the characteristic carbonyl vibrational band. The increase in metallic character of the group 15 elements also parallels the ease in formation of their complexes. This is due to the largely covalent character of arsenic compared to the highly ionic character of bismuth. The complete series of group 1 metal antimony(III) citrates have also been isolated and characterised in this work while a number of arsenic(III) ( + )-tartrate complexes were isolated using sodium and silver(!) counter ions (ionic radii 1.15 and 1.18A respectively).
35
Florea, Ana-Maria. "Toxicity of alkylated derivatives of arsenic, antimony and tin in vitro cellular uptake, cytotoxicity, genotoxic effects, perturbation of Ca2+ homeostasis, and cell death /". [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973570474.
36
Dippold, Angela C. "Detailed Geochemical Investigation of the Mineralogic Associations of Arsenic and Antimony Within the Avon Park Formation, Central Florida: Implications for Aquifer Storage and Recovery". [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002992.
37
Florea, Ana M. [Verfasser]. "Toxicity of Alkylated Derivatives of Arsenic, Antimony, and Tin in vitro : Cellular Uptake, Cytotoxicity, Genotoxic Effects, Perturbation of Ca2+ Homeostasis, and Cell Death / Ana M Florea". Aachen : Shaker, 2005. http://d-nb.info/118161998X/34.
38
Krejčí, Pavel. "Studium miniaturních zařízení pro kolekci hydridotvorných prvků v atomové spektroskopii". Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-233325.
Abstract (sommario):
Capability of a prototype of miniature collection device based on a strip of the molybdenum foil for collecting hydride forming elements (As, Se, Sb and Bi) was studied. The device was combined with a miniature hydrogen diffusion flame for detection by atomic absorption spectrometry. The conditions for trapping and subsequent vaporization of analytes of interest were optimized. A twin-channel hydride generation system was used for study of mutual interference effects of co-generated hydride forming elements. The influence of modification of the molybdenum surface with noble metals - Rh, Pt and Ir on trapping and vaporization processes was also studied and changes of microstructure of the foil surface after modification were investigated using scanning electron microscope equipped with energy dispersive x-ray analyzer and electron backscattered diffraction system. Complementary radiotracer and radiography experiments were performed in order to determine trapping efficiency and to assess the spatial distribution of collected analytes within the device. Practical application of the method was demonstrated on determination of antimony in water samples at trace level. Possibility of multi-element analysis was demonstrated by combining the collection device with atomization and excitation of the analyte in microwave induced plasma and with detection by atomic emission spectrometry method. The results of the experiments proved that tested miniature collection device is capable of trapping analytes that form volatile hydrides. This device can be coupled to various types of atomizers, typically used in spectrometry methods. Thus, very sensitive and specific detection of hydride forming elements can be performed.
39
Haffert, Laura, e n/a. "Metalloid mobility at historic mine and industrial processing sites in the South Island of New Zealand". University of Otago. Department of Geology, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090921.144328.
Abstract (sommario):
Rocks of the South Island of New Zealand are locally enriched in metalloids, namely arsenic (As), antimony (Sb) and boron (B). Elevated levels of As and Sb can be found in sulphide minerals mostly in association with mesothermal gold deposits, whereas B enrichment occurs in marine influenced coal deposits. The mobility of these metalloids is important because they can be toxic at relatively low levels (e.g. for humans >0.01 mg/L of As). Their mobilisation occurs naturally from background weathering of the bedrock. However, mining and processing of coal and gold deposits, New Zealand's most economically important commodities, can significantly increase metalloid mobility. In particular, historic mines and associated industrial sites are known to generate elevated metalloid levels because of the lack of site remediation upon closure. This work defines and quantifies geological, mining, post-mining and regional processes with respect to metalloid, especially As, mobility.
At the studied historic gold mines, the Blackwater and Bullendale mines, Sb levels in mineralised rocks were generally negligible (<14 ppm) compared to As (up to 10,000 ppm). Thus, Sb concentrations in solids and in water were too low to yield any meaningful information on Sb mobility. In contrast, dissolved As concentrations downstream from mine sites were found to be very high (up to 59 mg/L) (background = 10⁻� mg/L). In addition, very high As concentrations were found in residues (up to 40 wt%) and site substrate (up to 30 wt%) at the Blackwater processing sites (background < 0.05 wt%). Here, roasting of the gold ore converted the orginal As mineral, arsenopyrite, into the mineral arsenolite (As[III] trioxide polymorph) and volatilised the sulphur. The resultant sulphur-defficient chemical system is driven by arsenolite dissolution and differs significantly from mine sites where arsenopyrite is the main As source.
Arsenolite is significantly more soluble than arsenopyrite. In the surficial environment, arsenolite dissolution is limited by kinetics only, which are slow enough to preserve exposed arsenolite over decades in a temperate, wet climate. This process results in surface waters with up to ca. 50 mg/L dissolved As. In reducing conditions, dissolved As concentrations are also controlled by the solubility of arsenolite producing As concentrations up to 330 mg/L.
Field based cathodic stripping voltammetry showed that the As[III]/As[V] redox couple, in particular the oxidation of As[III], has a major control on system pH and Eh. Site acidification is mainly caused by the oxidation of As[III], resulting in a close link between As[V] concentrations and pH. Similarly, a strong correlation between calculated (Nernstian) and measured (electrode) Eh was found in the surface environment, suggesting that the overall Eh of the system is, indeed, defined by the As[III]/As[V] redox couple.
Once the metalloid is mobilised from its original source, its mobility is controlled by at least one of the following attenuation processes: (a) precipitation of secondary metalloid minerals, (b) co-precipitation with - or adsorption to - iron oxyhydroxide (HFO), or (c) dilution with background waters. The precipitation of secondary minerals is most favoured in the case of As due to the relatively low solubility of iron arsenates, especially at low pH (~0.1 mg/L). Observations suggest that scorodite can be the precursor phase to more stable iron arsenates, such as kankite, zykaite, bukovskyite or pharmacosiderite and their stability is mainly controlled by pH, sulphur concentrations and moisture prevalence. Empirical evidence indicates that the sulphur-containing minerals zykaite and bukovskyite have a similar pH dependence to scorodite with solubilities slightly lower than scorodite and kankite. If dissolved As concentrations decline, iron arsenates potentially become unstable. Their dissolution maintains a pH between 2.5 and 3.5. This acidification process is pivotal with respect to As mobility, especially in the absence of other acidification processes, because iron arsenates are several orders of magnitude more soluble in circum-neutral pH regimes (~100 mg/L). From this, it becomes apparent that external pH modifications, for example as part of a remediation scheme, can significantly increase iron arsenate solubility and resultant As mobility. In contrast to As, the precipitation of secondary Sb and B minerals is limited by their high solubilities, which are several orders of magnitude higher than for iron arsenates. Thus, secondary Sb and B minerals are restricted to evaporative waters, from which they can easily re-mobilised during rain events.
Metalloid adsorption to HFO is mainly controlled or limited by the extent of HFO formation, which in turn is governed by the availability of Fe and prevailing Eh-pH conditions. Thus, mineralisation styles and associated geochemical gradients, in particular pyrite abundance, can control the amount of HFO and consequent metalloid attenuation, and these can vary even within the same goldfleld. Furthermore, it was found that there is a mineralogical gradation between ferrihydrite with varying amounts of adsorbed As, amorphous iron arsenates and crystalline iron arsenates, suggesting that the maturity of mine waste is an important factor in As mineralogy.
Once dissolved metalloids enter the hydrosphere, dilution is the main control on metalloid attenuation, which is especially pronounced at the inflow of tributaries. Dilution is, therefore, closely related to the size and frequency of these tributaries, which in turn are controlled by the regional topography and climate. Dilution is a considerably less effective attenuation mechanism and anomalous metalloid concentrations from mining related sites can persist for over 10 km downstream.
The complex and often inter-dependent controls on metalloid mobility mean that management decisions should carefully consider the specific site geochemistry to minimize economic, health and environmental risks that can not be afforded.
On a regional scale, background metalloid flux determines the downstream impact of an anomalous metalloid source upstream. For example, the Bullendale mine is located in a mountainous region, where rapidly eroding slopes expose fresh rock and limit the extent of soil cover and chemical weathering. Consequently, the background As flux is relatively low and As point sources, such as the Bullendale mine, present a significant contribution to the downstream As flux. In contrast, the bedrock at the Blackwater mine has undergone deep chemical weathering, resulting in an increased background mobilisation of As. Thus, the Prohibition mill site discharge, for example, contributes only about 10% to the downstream As flux. This information is relevant to site management decisions because the amount of natural background metalloid mobilisation determines whether site remediation will influence downstream metalloid chemistry on a regional scale.
40
FONTANELLA, MARIA CHIARA. "APPLICAZIONE DI DIFFERENTI TECNICHE PER LA DETERMINAZIONE DELL’ARSENICO NELLA CATENA ALIMENTARE UMANA: DALL’ACQUA DI FALDA ALLA TAVOLA". Doctoral thesis, Università Cattolica del Sacro Cuore, 2013. http://hdl.handle.net/10280/1958.
Abstract (sommario):
Lo scopo della tesi è di caratterizzare i rischi per la salute umana, che derivano dall’inquinamento delle acque (acque sotterranee) e dal cibo (riso) tramite l’applicazione e lo sviluppo di nuove tecniche analitiche. La tecnica “diffusive gradients in thin films (DGT)” con resina a base di ferrihydrite, è stata studiata per l'accumulo delle forme inorganiche (As(III) e As(V)) e organiche (DMA(V) e MMA(V)) di Arsenico in matrici acquose. I DGT sono stati applicati su campioni di acque sotterranee, raccolti in sei diverse città del Nord Italia, dove la concentrazione di As è molto alta. Antimonio (Sb) è associato all’As in diversi studi perché le proprietà fisiche e chimiche di questi due elementi sono simili, ed esso è stato recentemente riconosciuto come contaminante dell'acqua. In questa tesi per la prima volta sono state riportate le prestazioni dettagliate dei DGT con ferrihydrite, impiegati in soluzioni acquose di Sb(III) e Sb(V). L’analisi delle forme chimiche di Sb(III) e Sb(V) in campioni acquosi è stata realizzata con l’applicazione della diluizione isotopica. In generale il riso, a differenza di altri prodotti alimentari di origine terrestre, contiene quantità significative di Arsenico inorganico. L’analisi della speciazione di As è stata realizzata in 70 campioni di riso italiano, rappresentativo di diversi tipi di coltivazione. Le forme più abbondanti nel riso erano As(III) e DMA(V). Inoltre è stato interessante studiare la localizzazione dell’As nel chicco di riso, sottoposto a diversi processi di lavorazione (risone, riso integrale e lavorato con o senza parboiling), perché sia la distribuzione che la presenza delle diverse forme chimiche nel chicco sono fattori chiave che controllano la biodisponibilità del contaminante. La distribuzione dell’ As nei chicchi di riso di due varietà (Gladio e Ronaldo) sottoposti a diversi processi, è stato determinato con Laser Ablation ICP-MS. In realtà il contenuto di As era più alto nei chicchi di riso non-parboiled rispetto a quello parboiled. La relazione tra intensità dell’As e le varie parti del chicco di riso ha rivelato che i livelli di As diminuisco dalla parte esterna verso la posizione centrale, mentre i valori di As sembrano essere simili tra la parte media e interna dei non parboiled.The aim of this thesis was to explore new analytical techniques as well as to carry out further characterisations of human health risks, which derive from water pollution, in particular groundwater, and food, in particular rice. The prevention of water pollution is an environmental aspect, that includes monitoring of both natural enrichment and outside pollution with routine analysis but also with new techniques, e.g. the application of passive sampling techniques and advanced technologies. The diffusive gradients in thin films (DGT) technique with ferrihydrite adsorbent, has been investigated for the accumulation of different species of Arsenic (As), like Inorganic Species (arsenite and arsenate) and Organic Arsenic (dimethylarsinic and monomethylarsenate) in aqueous matrix. To evaluate the performance of DGT method for accumulation of arsenic species, after deployment in synthetic solutions, DGT devices were carried out on groundwaters collected in six different towns in the North of Italy, where the As concentration is very high. Recently, health effects at arsenic exposures have been observed in areas where levels of inorganic As in drinking water are not excessive. Antimony (Sb) is associated to As in several studies because the physical and chemical properties of these two elements are similar, and it has been recently recognized as water contaminant. In this thesis I reported for the first time detailed performance characteristics of the Fe-oxide gel associated to DGT devices deployed in known aqueous solutions of trivalent and pentavalent Sb. Speciation analysis of Sb(III) and Sb(V) in aqueous samples was performed through extraction and on-line determination of isotope dilution concentration after a chromatographic separation. Generally rice, unlike food products of terrestrial origin, contains significant amounts of inorganic arsenic. Recently some Government Organizations (e.g. EFSA) debated the possibility to set an upper limit for total and inorganic arsenic in rice. Arsenic speciation was realized in 70 Italian rice samples from different representative cultivation conditions. The most abundant forms in rice were As(III) and DMA(V). After that, it was fundamental to investigate the localization of As in rice grains in different processes (raw, brown and milled rice with or without parboiling technique), because both speciation and distribution throughout the grain are key factors controlling bioavailability of the contaminant. The As distribution in rice grains of two varieties (Gladio and Ronaldo) from different processes, was determined by LA-ICP-MS. The distribution of As varied between the various parts of the grains (exterior, medium and interior part). During parboiling, the partial boiling of food as the first step in the cooking process, arsenic might have released from the grain to the boiling water. Thus, parboiling of rice grain may reduce the magnitude of arsenic intake in human body. Actually the As content was higher in non-parboiled rice grain than in parboiled rice. The relationship between As intensities and the different parts of rice grain revealed that As levels decreased from the external part towards the middle position, and then the intensity values seem to be similar between medium and internal part in non parboiled products.
41
FONTANELLA, MARIA CHIARA. "APPLICAZIONE DI DIFFERENTI TECNICHE PER LA DETERMINAZIONE DELL’ARSENICO NELLA CATENA ALIMENTARE UMANA: DALL’ACQUA DI FALDA ALLA TAVOLA". Doctoral thesis, Università Cattolica del Sacro Cuore, 2013. http://hdl.handle.net/10280/1958.
Abstract (sommario):
Lo scopo della tesi è di caratterizzare i rischi per la salute umana, che derivano dall’inquinamento delle acque (acque sotterranee) e dal cibo (riso) tramite l’applicazione e lo sviluppo di nuove tecniche analitiche. La tecnica “diffusive gradients in thin films (DGT)” con resina a base di ferrihydrite, è stata studiata per l'accumulo delle forme inorganiche (As(III) e As(V)) e organiche (DMA(V) e MMA(V)) di Arsenico in matrici acquose. I DGT sono stati applicati su campioni di acque sotterranee, raccolti in sei diverse città del Nord Italia, dove la concentrazione di As è molto alta. Antimonio (Sb) è associato all’As in diversi studi perché le proprietà fisiche e chimiche di questi due elementi sono simili, ed esso è stato recentemente riconosciuto come contaminante dell'acqua. In questa tesi per la prima volta sono state riportate le prestazioni dettagliate dei DGT con ferrihydrite, impiegati in soluzioni acquose di Sb(III) e Sb(V). L’analisi delle forme chimiche di Sb(III) e Sb(V) in campioni acquosi è stata realizzata con l’applicazione della diluizione isotopica. In generale il riso, a differenza di altri prodotti alimentari di origine terrestre, contiene quantità significative di Arsenico inorganico. L’analisi della speciazione di As è stata realizzata in 70 campioni di riso italiano, rappresentativo di diversi tipi di coltivazione. Le forme più abbondanti nel riso erano As(III) e DMA(V). Inoltre è stato interessante studiare la localizzazione dell’As nel chicco di riso, sottoposto a diversi processi di lavorazione (risone, riso integrale e lavorato con o senza parboiling), perché sia la distribuzione che la presenza delle diverse forme chimiche nel chicco sono fattori chiave che controllano la biodisponibilità del contaminante. La distribuzione dell’ As nei chicchi di riso di due varietà (Gladio e Ronaldo) sottoposti a diversi processi, è stato determinato con Laser Ablation ICP-MS. In realtà il contenuto di As era più alto nei chicchi di riso non-parboiled rispetto a quello parboiled. La relazione tra intensità dell’As e le varie parti del chicco di riso ha rivelato che i livelli di As diminuisco dalla parte esterna verso la posizione centrale, mentre i valori di As sembrano essere simili tra la parte media e interna dei non parboiled.The aim of this thesis was to explore new analytical techniques as well as to carry out further characterisations of human health risks, which derive from water pollution, in particular groundwater, and food, in particular rice. The prevention of water pollution is an environmental aspect, that includes monitoring of both natural enrichment and outside pollution with routine analysis but also with new techniques, e.g. the application of passive sampling techniques and advanced technologies. The diffusive gradients in thin films (DGT) technique with ferrihydrite adsorbent, has been investigated for the accumulation of different species of Arsenic (As), like Inorganic Species (arsenite and arsenate) and Organic Arsenic (dimethylarsinic and monomethylarsenate) in aqueous matrix. To evaluate the performance of DGT method for accumulation of arsenic species, after deployment in synthetic solutions, DGT devices were carried out on groundwaters collected in six different towns in the North of Italy, where the As concentration is very high. Recently, health effects at arsenic exposures have been observed in areas where levels of inorganic As in drinking water are not excessive. Antimony (Sb) is associated to As in several studies because the physical and chemical properties of these two elements are similar, and it has been recently recognized as water contaminant. In this thesis I reported for the first time detailed performance characteristics of the Fe-oxide gel associated to DGT devices deployed in known aqueous solutions of trivalent and pentavalent Sb. Speciation analysis of Sb(III) and Sb(V) in aqueous samples was performed through extraction and on-line determination of isotope dilution concentration after a chromatographic separation. Generally rice, unlike food products of terrestrial origin, contains significant amounts of inorganic arsenic. Recently some Government Organizations (e.g. EFSA) debated the possibility to set an upper limit for total and inorganic arsenic in rice. Arsenic speciation was realized in 70 Italian rice samples from different representative cultivation conditions. The most abundant forms in rice were As(III) and DMA(V). After that, it was fundamental to investigate the localization of As in rice grains in different processes (raw, brown and milled rice with or without parboiling technique), because both speciation and distribution throughout the grain are key factors controlling bioavailability of the contaminant. The As distribution in rice grains of two varieties (Gladio and Ronaldo) from different processes, was determined by LA-ICP-MS. The distribution of As varied between the various parts of the grains (exterior, medium and interior part). During parboiling, the partial boiling of food as the first step in the cooking process, arsenic might have released from the grain to the boiling water. Thus, parboiling of rice grain may reduce the magnitude of arsenic intake in human body. Actually the As content was higher in non-parboiled rice grain than in parboiled rice. The relationship between As intensities and the different parts of rice grain revealed that As levels decreased from the external part towards the middle position, and then the intensity values seem to be similar between medium and internal part in non parboiled products.
42
Runtti, H. (Hanna). "Utilisation of industrial by-products in water treatment:carbon-and silicate-based materials as adsorbents for metals and sulphate removal". Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526212630.
Abstract (sommario):
Abstract Pollutant (such as metals and sulphate) contamination exists in the wastewaters of many industries, including mining operations, metal plating facilities, and tanneries. Adsorption is one of the most commonly used processes for the removal of pollutants from waters and wastewaters due to its high efficiency and simple operation. Activated carbon is the most frequently used adsorbent material, although its high cost inhibits its widespread use in wastewater treatment. Therefore, there is a need to develop other adsorbents from alternative inexpensive raw materials such as locally available industrial and mineral waste and by-products. The aim of this thesis was to study the possibility of using industrial waste materials such as carbon residue, metakaolin, blast-furnace slag and analcime as an inexpensive sorbent for iron, copper, nickel, arsenic, antimony and sulphate removal from aqueous solutions. To enhance their adsorption capacity, different chemical treatments (i.e. activation, modification, geopolymerisation) were performed. As a result, the level of removal of iron, copper and nickel by carbon residue and zinc chloride activated carbon residue was higher than that by the commercial activated carbon. Iron chloride modified carbon residue was the most effective sorbent material for sulphate removal when compared to the other studied chemically modified/activated carbon residues. Blast-furnace slag and metakaolin geopolymers as well as their raw materials, were examined for the simultaneous removal of nickel, arsenic and antimony from the spiked mine effluent. In the case of blast-furnace slag, geopolymerisation clearly increased the efficiency of nickel, arsenic and antimony removal to a beneficial level. The barium chloride modified blast-furnace-slag geopolymer was a very efficient sorbent material for sulphate removal and it could thus be a technically feasible sulphate sorbent for wastewater treatment (e.g. in the mining industry in applications in which very low sulphate levels are desired). Barium chloride modified acid washed analcime could also be a potential sorbent for sulphate removalTiivistelmä Teollisuuden jätevedet kuten kaivosvedet ja metalliteollisuuden prosessien jätevedet voivat sisältää monenlaisia haitallisia ja jopa myrkyllisiä aineita kuten metalleja ja sulfaattia. Adsorptiota käytetään yleisesti esimerkiksi metallien ja orgaanisten yhdisteiden poistossa vesiliuoksista, koska se on tehokas ja yksinkertainen menetelmä. Aktiivihiili on yleisimmin käytetty adsorbenttimateriaali vedenpuhdituksessa, mutta sen hinta joissain tapauksissa rajoittaa sen käyttöä. Tämän vuoksi on tarvetta kehittää vaihtoehtoisia adsorbenttimateriaaleja edullisista raaka-aineista. Viime vuosien aikana on raportoitu mm. teollisuus- ja mineraalijätteistä, joita voidaan hyödyntää vesien ja jätevesien puhdistuksessa. Tämän työn tavoitteena oli hyödyntää teollisuudesta muodostuvia jätemateriaaleja (hiilijäännös, metakaoliini, masuunikuona ja analsiimi) raudan, kuparin, nikkelin, arseenin, antimonin tai sulfaatin poistossa malli- ja jätevesistä. Materiaaleja käsiteltiin erilaisilla kemikaaleilla (aktivointi, modifiointi tai geopolymerointi), jotta niiden adsorptiotehokkuudet paranisivivat poistettavia aineita kohtaan. Tulokset osoittivat, että raudan, kuparin ja nikkelin poisto oli sekä käsittelemättömällä että sinkkikloridilla aktivoidulla hiilijäännöksellä korkeampi kuin kaupallisella aktiivihiilellä. Arseenin, nikkelin ja antimonin poistoa kaivosvedestä tutkittiin masuunikuona- ja metakaoliinigeopolymeereillä, joista masuunikuonageopolymeeri osoittautui tehokkaimmaksi metallien poistajaksi. Bariumkloridilla modifioitu masuunikuonageopolymeeri puolestaan poisti erittäin tehokkaasti sulfaattia kaivoksen jätevedestä. Rautakloridilla modifioitu hiilijäännös ja happopesty bariumkloridilla modifioitu analsiimi osoittatuivat myös lupaavaksi materiaaliksi sulfaatin poistossa
43
Luukkonen, T. (Tero). "New adsorption and oxidation-based approaches for water and wastewater treatment:studies regarding organic peracids, boiler-water treatment, and geopolymers". Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526210797.
Abstract (sommario):
Abstract This thesis examines three different areas of water treatment technology: the application of organic peracids in wastewater treatment; the removal of organic residues from boiler make-up water; and the use of geopolymers as sorbents. The main advantages of peracids as alternative wastewater disinfectants are their effective antimicrobial properties and high oxidation power, as well the absence of harmful disinfection by-products after their use. Performic, peracetic and perpropionic acids were compared in laboratory-scale disinfection, oxidation and corrosion experiments. From the techno-economical point of view, performic acid proved to be the most effective disinfectant against E. coli and fecal enterococci. However, in the bisphenol-A oxidation experiments, no advantages compared to hydrogen peroxide use were observed. It was also determined that corrosion rates on stainless steel 316L were negligible, while carbon steel seemed unsuitable in terms of corrosion for use with peracids even in low concentrations. Organic compounds in the boiler plant water-steam cycle thermally decompose and form potentially corrosive species. Activated carbon filtration was confirmed to be a suitable method for the removal of organic residue from deionized boiler make-up water. No significant differences in terms of treatment efficiency between commercial activated carbons were observed. However, acid washing as a pre-treatment reduced the leaching of impurities from new carbon beds. Nevertheless, a mixed-bed ion exchanger was required to remove leached impurities, such as silica and sodium. Geopolymers, or amorphous analogues of zeolites, can be used as sorbents in the treatment of wastewater. Metakaolin and blast-furnace-slag geopolymers showed positive potential in the treatment of landfill leachate (NH4+ ) and mine effluent (Ni, As, Sb)Tiivistelmä Tämä väitöskirja käsittelee kolmea erillistä vedenkäsittelyteknologian osa-aluetta: orgaanisten perhappojen käyttöä jäteveden käsittelyssä, orgaanisten jäämien poistoa suolavapaasta kattilalaitoksen lisävedestä ja geopolymeerien sovelluksia vedenkäsittelysorbentteina. Orgaanisten perhappojen pääasialliset edut verrattuna kilpaileviin tekniikoihin ovat hyvä desinfiointiteho, korkea hapetuspotentiaali ja desinfioinnin sivutuotteiden muodostumattomuus. Permuurahais-, peretikka- ja perpropaanihapon vertailu osoitti permuurahaishapon olevan kemikaaleista tehokkain E. coli - ja enterokokkibakteerien inaktivoinnissa kustannus- ja teknisistä näkökulmista. Hapetuksessa, jossa käytettiin bisfenoli-A:ta malliaineena, ei kuitenkaan havaittu etua verrattuna edullisempaan vetyperoksidiin. Ruostumattoman teräksen (316L) pinnalla ei havaittu merkittävää korroosiota, kun taas hiiliteräs ei sovellu käytettäväksi perhappojen kanssa. Orgaaniset jäämät kattilalaitoksen vesi-höyrykierrossa hajoavat termisesti pienen moolimassan hapoiksi ja aiheuttavat korroosioriskin. Aktiivihiilisuodatuksen todettiin olevan soveltuva menetelmä orgaanisten jäämien poistoon lisävedestä. Aktiivihiililaatujen välillä ei havaittu merkittäviä eroja, mutta happopesu aktiivihiilen esikäsittelynä vähensi hiilestä liukenevien epäpuhtauksien määrää. Geopolymeerit ovat zeoliittien amorfisia analogeja ja niiden ioninvaihtokykyä voidaan hyödyntää vedenkäsittelysovelluksissa. Metakaoliini- ja masuunikuonapohjaisten geopolymeerien todettiin olevan lupaavia materiaaleja malliliuosten, kaatopaikan suotoveden ja kaivoksen purkuveden käsittelyssä poistettaessa ammoniumia, nikkeliä, arseenia ja antimonia
44
Boiron, Marie-Christine. "MINERALISATIONS A Au, As, Sb, ALTERATIONS HYDROTHERMALES ET FLUIDES ASSOCIES DANS LE BASSIN DE VILLERANGES (COMBRAILLES, MASSIF CENTRAL FRANCAIS)". Poitiers, 1987. http://www.theses.fr/1987POIT2278.
Abstract (sommario):
Trois evenements d'intensite, d'importance et d'interet metallogenique differents sont reconnus: 1) l'ensemble des series viseennes est affecte d'abord par une alteration a chlorite-albite-anatase. 2) les rejeux tardifs de la zone de cisaillement marche-combrailles provoquent d'intenses fracturations auxquelles sont associees d'importantes circulations de fluides hydrothermaux. Plusieurs episodes successifs d'alteration et de mineralisation sont enregistres dans la zone des farges. 3) des reouvertures tardives du systeme permettent des circulations de fluides responsables de la cristallisation de calcite, de quartz microcristallin et de pyrite
45
McCabe, S. "Novel methods for the determination of arsenic, antimoney and selenium in single cell protein". Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381347.
46
Schütt, Thomas. "Halogen-, Azid- und Koordinationsverbindungen des Arsens und Antimons". [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963037811.
47
Schütt, Thomas. "Halogen-, Azid- und Koordinationsverbindungen des Arsens und Antimons". Diss., lmu, 2001. http://nbn-resolving.de/urn:nbn:de:bvb:19-3668.
48
SILVA, LARISSA de S. "Avaliação da concentração de metais e elementos terras raras em amostras de sedimentos dos reservatórios dos sistemas Billings e Guarapiranga". reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/28040.
Abstract (sommario):
Submitted by Pedro Silva Filho (pfsilva@ipen.br) on 2017-11-22T17:15:11Z
No. of bitstreams: 0Made available in DSpace on 2017-11-22T17:15:11Z (GMT). No. of bitstreams: 0
O excessivo processo de urbanização da Região Metropolitana de São Paulo resultou na perda das características naturais dos seus cursos d\'água ocasionando profundas alterações nos regimes de vazão e de qualidade. O objetivo desse estudo foi avaliar a concentração de metais tóxicos, os semi-metais As, Sb e Se e os elementos terras raras, presentes em amostras de sedimento superficiais coletadas nos Reservatórios Billings, Guarapiranga e Rio Grande. Os elementos Ag, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sb, Se e Zn foram determinados pela técnica de Espectrometria de Emissão Ótica com Plasma Indutivamente Acoplado (ICP OES). Alguns elementos maiores, traço e elementos terras raras (Ce, Eu, La, Lu, Nd, Sm, Tb e Yb) foram determinados pela técnica de Análise por Ativação Neutrônica Instrumental (INAA). A concentração de Hg total foi determinada pela técnica Espectrometria de Absorção Atômica com Geração de Vapor Frio (CVAAS). A validação das metodologias foi realizada por meio da análise de materiais de referência certificados. Para avaliar as possíveis fontes de contaminação antrópicas foram utilizadas as ferramentas de fator de enriquecimento (FE) e o índice de geoacumulação (IGeo). Os resultados obtidos pelas técnicas foram comparados com os valores orientadores TEL e PEL estabelecidos pelo CCME (Canadian Council of Ministers of the Environment) e adotados pela CETESB. Todos os pontos analisados apresentaram valores > TEL para todos os metais e dois pontos da represa Billings (BILL02100 e 02030), valores > PEL para As, Cr, Cu, Hg, Ni, Pb e Zn, provavelmente em decorrência do recebimento das águas do Rio Pinheiros e das bacias de drenagem do ribeirão Cocaia e Bororé. Os valores de FE e IGeo calculados apontaram possíveis contaminações antrópicas para Sb e Se para os elementos determinados por ICP OES e de As, Cr, Sb e Zn, por INAA. O reservatório Billings apresentou, em geral, as maiores concentrações para os elementos analisados, indicando uma má qualidade de seus sedimentos. Este estudo confirma a necessidade de um monitoramento frequente da qualidade do sedimento nos reservatórios estudados como procedimento indispensável para avaliação periódica da qualidade das bacias, considerando sua importância no fornecimento de água para a Região Metropolitana de São Paulo.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
49
Casiot, Corinne. "Développement de techniques analytiques couplées (HPLC-ICP-MS et EC-ICP-MS) pour la spéciation de métalloi͏̈des (arsenic, sélénium, antimoine et tellure)". Pau, 1999. http://www.theses.fr/1999PAUU3026.
Abstract (sommario):
Les éléments traces et en particulier les métalloïdes tels que l'arsenic, le sélénium, l'antimoine et le tellure peuvent se présenter dans l'environnement sous différentes formes chimiques, qui conditionnent leur toxicité, leur biodisponibilité et leur capacité à migrer. Ce travail présente le développement de deux techniques analytiques de spéciation multiélémentaire, associant une technique séparative (chromatographie liquide, électrophorèse capillaire) et un détecteur spécifique et très sensible, l'ICP-MS. La chromatographie d'échange d'anions couplée à l'ICP-MS a permis la séparation simultanée de onze espèces organiques et inorganiques de l'arsenic (As III, As V, MMa, DMa), du sélénium (Se IV, Se VI, SeCyst, SeMet), de l'antimoine (Sb V) et du tellure (Te IV et Te VI). Les limites de détection, comprises entre 0,02 et 3 g/l, ont permis l'analyse d'extraits de sols et de tissus biologiques (poisson, levures). Plusieurs protocoles ont été testés pour l'extraction du sélénium contenu dans une levure. Différentes classes de composés séléniés (protéines, acides aminés, composés inorganiques) ont été mises en évidence par chromatographie d'exclusion stérique. L'adénosyl-séléhomocystéine a été identifiée par spectrométrie de masse electrospray. Un couplage entre l'électrophorèse capillaire (EC) et l'ICP-MS a été développé. Trois nébuliseurs ont été testés pour l'interface : le Babington, le MCN-100 et le Micromist. Ce dernier a permis des séparations reproductibles et une amélioration de la sensibilité par rapport à l'UV. Les limites de détection sont comprises entre 6 et 58 g/l pour les espèces étudiées de As, Se, Sb et Te. L'analyse d'extraits de sols a montré les possibilités de cette technique pour l'analyse d'échantillons réels.
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Souza, Antonio Gouveia de. "Termoquimica de quelatos de dialquilditiocarbamatos envolvendo fosforo, arsenio, antimonio e bismuto trivalente : alguns aspectos termoquimicos de alcoxidos e tris (dietilamido) de arsenio (III)". [s.n.], 1986. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250061.
Abstract (sommario):
Orientador : Claudio AiroldiTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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