The order of OH groups in the crystal structure of SbC2O4OH, a potential precursor in the synthesis of ternary oxides, was debated. Neutron diffraction on the deuteride SbC2O4OD revealed disordered OD groups with half occupation for deuterium atoms on either side of a mirror plane (SbC2O4OD at T = 298(1) K: Pnma, a = 582.07(3) pm, b = 1128.73(5) pm, c = 631.26(4) pm). O–H stretching frequencies are shifted by a factor of 1.35 from 3390 cm−1 in the hydride to 2513 cm−1 in the deuteride as seen in infrared spectra. SbC2O4OH suffers radiation damage in a synchrotron beam, which leaves a dark amorphous residue. Thermal decomposition at 564 K yields antimony oxide, carbon dioxide, carbon oxide, and water in an endothermic reaction. When using SbC2O4OH as a precursor in reactions, however, ternary oxides are only formed at much higher temperatures.

No description available.

Novel diorganoantimony(III) fluorides containing ligands with pendant arms, R2SbF (5), (R)PhSbF (6) [R = 2-(2′,6′-iPr2C6H3N[double bond, length as m-dash]CH)C6H4], R′′2SbF (7) and (R′′)PhSbF (8) [R′′ = 2-(Me2NCH2)C6H4], were prepared via the ionic derivatives [R2Sb]+[PF6]− (1), [(R)PhSb]+[PF6]− (2), [R′′2Sb]+[SbF6]− (4) and [(R′′)PhSb]+[SbF6]− (obtained in situ) by treatment with [Bu4N]F·3H2O. The ionic species used as starting materials as well as [R′2Sb]+[PF6]− (3) [R′ = 2-(2′,4′,6′-Me3C6H2N[double bond, length as m-dash]CH)C6H4] were obtained from the corresponding bromides or chlorides and Tl[PF6] or Ag[SbF6]. The compounds were investigated by multinuclear NMR spectroscopy in solution, MS and IR spectroscopy in the solid state. The molecular structures of the ionic species 1·2CH2Cl2 and 3·2CHCl3 as well as of the fluorides 5–8 were determined by single-crystal X-ray diffraction. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Also aged bottles are safer to use than new bottles because their chemical leaching was found to be lower than that of new bottles. This study recommends the reassessment of the absence of international guidelines for acetaldehyde in water and foods. The study also recommends that the amount of acetaldehyde that can be added to soft drinks as flavouring agent should be below the specific migration limit (SML) for migration of acetaldehyde from PET bottle into bottle contents. This is essential since the SML was designed to ensure that exposure to acetaldehyde, as a result of intake of bottled water and soft drinks in PET bottles, is below the tolerable daily intake (TDI) for acetaldehyde. As antimony was reported to go beyond the safe limits in some Nigerian bottled water and soft drinks after 11 months of storage this study discourages the use of bottle contents stored for a very long time.

No description available.

The subject of this thesis was creating of teaching material for an interactive whiteboard using ActivInspire program. The material was created in a form of interactive presentations designed to be used in chemistry lessons at secondary schools. The theme of these presentations was the 15th group of the periodic table of elements. The thesis also includes a description of the way the presentations were made and instructions for teachers how to work with them.

Antimony film electrode was studied for the use in a voltammetric analysis of organic compounds. The substance chosen as an analyte was trifluralin, which is used as a pesticide. The comparison of different substrate electrodes was carried out between five electrodes, which were gold, silver, copper, polished amalgam and glassy carbon electrode (GCE). Best performance was observed on antimony film glassy carbon electrode (SbFGCE). It provided higher sensitivity and lower limit of quantification in comparison with bare GCE. The antimony film was stable and it provided good reproducibility (RSD = 5.2 %). Parameters of an electrochemical preparation of SbFGCE were optimized. Conditions for determination of concentration of trifluralin were optimized on newly prepared SbFGCE. The best conditions were in a solution of methanol and 0.1 M hydrochloric acid in 1:1 ratio measured by differential pulse voltammetry. The limit of quantification was determined as 1.2·10-6 mol·l-1 . A direct voltammetric measurement on SbFGCE was carried out in a model river sample. Lower limits of quantification were achieved with solid phase extraction (SPE). Recovery values were 86 ± 8 % in deionized water with a preconcentration factor of 125. The limit of quantification was lowered to value 1.1·10-8 mol·l-1 . The extraction...

Antimony (Sb) is an element of increasing concern as an environmental contaminant. Geothermal systems are a potential source of Sb in the fresh waters of New Zealand’s North Island, but little is known about the element’s behaviour within geothermal fluids, and even less about the eventual fate of geothermally produced Sb. The purpose of this thesis was to determine the factors controlling geothermal Sb behaviour in a range of environments, in order to begin to develop an understanding of the eventual fate of Sb produced from geothermal systems. Factors controlling Sb precipitation at two New Zealand geothermal power stations, were determined using field measurements and geochemical model predictions. Approximately 75 % of the incoming Sb, which ranged from 960 – 1650 μg/kg in the incoming fluids was removed from solution within the Ngawha and Rotokawa power stations. It was found that changes in pH and temperature were the most important factors controlling stibnite (Sb2S3) precipitation. Thermodynamic databases could be used to model this precipitation process, once updated with recent published Sb2S3 solubility data. The mobility of Sb from Sb2S3 precipitates in geothermal features at Wai-O-Tapu and Waimangu, two New Zealand geothermal fields, were investigated. At Wai-O-Tapu, daytime variations in aqueous Sb concentrations from the discharge of Champagne Pool may be due to to changing sulfide-sulfate equilibria coupled with photosynthetic bacterial processes. While daytime concentrations of Sb approached 200 μg/kg, most of the Sb remobilised by such mechanisms appears to be removed by adsorption onto suspended particulate material (SPM) or reprecipitation (as Sb2S3) in an anoxic, low pH lake feature downstream. Concentrations of Sb in the discharge from Alum Lake were below the analytical detection limit (<0.2 μg/kg). At Waimangu, these daytime fluctuations were not observed in the discharge of Frying Pan Lake, and concentrations of Sb were ~13 μg/kg. In the absence of any downstream acidic waters, no precipitation was observed and only minor adsorption onto SPM was observed. Most of the Sb produced from Frying Pan Lake is therefore transported into Lake Rotomahana, the system’s receiving environment. Natural Sb removal processes in receiving (non-geothermal) environments were also assessed. In the Waikato River, Sb concentrations were low (~1 μg/kg), compared to those observed in geothermal environments studied. The most important process was adsorption to SPM, which is enhanced at low (< 5) pH conditions, or in the anoxic base of stratified lakes. In Lake Ohakuri, which was stratified during the summer of 2007, there was also the potential for the removal of Sb as Sb2S3 in the presence of sulfide species that form in the anoxic layer. There was evidence that the adsorption of Sb changes with changing Fe concentrations in suspended particulate material, and therefore Sb adsorption was higher in winter than in summer. The behaviour of Sb was conservative in the Port Waikato estuary at the mouth of the river. Throughout the research, Sb was compared to arsenic (As), a metalloid previously thought to exhibit behaviour similar to Sb in aquatic environments. It was found that while any removal processes shown to affect Sb will also affect As, the inverse did not necessarily apply. Arsenic will adsorb more readily to SPM than Sb and, while there was evidence for bioaccumulation of As by geothermal algae and freshwater macrophytes, there was no such evidence for Sb. Therefore, if geothermally-derived Sb and As did ever significantly contaminate a downstream environment, it should not be assumed that the processes mitigating As contamination will necessarily also apply to Sb.

Arsenic and antimony are important trace elements in magmatic-hydrothermal systems, geothermal systems and epithermal deposits, but their partitioning behavior between melt and aqueous fluid is not well understood. The partitioning of arsenic and antimony between aqueous fluid and granitic melt has been studied in the system SiO2-Al2O3-Na2O-K2O-H2O at 800 degree C and 200 MPa. The partition coefficients of As and Sb between aqueous fluid and melt, are 1.4 +- 0.5 and 0.8 +- 0.5, respectively. The partitioning of As is not affected by aluminum saturation index (ASI) or SiO2 content of the melt, or by oxygen fugacity under oxidized conditions (log fO2 > the nickel-nickel oxide buffer, NNO). The partitioning of Sb is independent of and SiO2 content of the melt. However, aluminum saturation index (ASI) does affect Sb partitioning and Sb partition coefficient for peralkaline melt (0.1 +- 0.01) is much smaller than that for metaluminous melts (0.8 +- 0.4) and that for peraluminous melts (1.3 +- 0.7). Thermodynamic calculations show that As(III) is dominant in aqueous fluid at 800 degree C and 200 MPa and XPS analysis of run product glass indicate that only As(III) exists in melt, which confirms the finding that does not affect As partitioning between fluid and melt. XPS analysis of run product glass show that Sb(V) is dominant in melt at oxidized conditions (log fO2 > -10). The peralkaline effect only exhibits on Sb partitioning, not on As partitioning at oxidized conditions, which is consistent with the x-ray photoelectron spectroscopy (XPS) measurements that As(III) and Sb(V) are dominant oxidation states in melt under oxidized conditions, because the peralkaline effect is stronger for pentavalent than trivalent cations. Permeable reactive barriers (PRBs) are an alternative technology to treat mine drainage containing sulfate and heavy metals. Two column experiments were conducted to assess the suitability of an organic carbon (OC) based reactive mixture and an Fe0-bearing organic carbon (FeOC) based reactive mixture, under controlled groundwater flow conditions. The organic carbon (OC) column showed an initial sulfate reduction rate of 0.4 μmol g(oc)-1 d-1 and exhausted its capacity to promote sulfate reduction after 30 pore volumes (PVs), or 9 months of flow. The Fe0-bearing organic carbon (FeOC) column sustained a relative constant sulfate reduction rate of 0.9 μmol g(oc)-1 d-1 for at least 65 PVs (17 months). The microbial enumerations and isotopic measurements indicate that the sulfate reduction was mediated by sulfate reducing bacteria (SRB). The cathodic production of H2 by anaerobic corrosion of Fe probably is the cause of the difference in sulfate reduction rates between the two reactive mixtures. Zero-valent iron can be used to provide an electron donor in sulfate reducing PRBs and Fe0-bearing organic carbon reactive mixture has a potential to improve the performance of organic carbon PRBs. The δ34S values can be used to determine the extent of sulfate reduction, but the fractionation is not consistent between reactive materials. The δ13C values indicate that methanogenesis is occurring in the front part of both columns. Arsenic and antimony in groundwater are great threats to human health. The PRB technology potentially is an efficient and cost-effective approach to remediate organic and inorganic contamination in groundwater. Two column experiments were conducted to assess the rates and capacities of organic carbon (OC) PRB and Fe-bearing organic carbon (FeOC) PRB to remove As and Sb under controlled groundwater flow conditions. The average As removal rate for the OC column was 13 nmole day-1 g-1 (dry weight of organic carbon) and its removal capacity was 11 μmole g-1 (dry weight of organic carbon). The remove rate of the FeOC material was 165 nmole day-1 g-1 (dry weight of organic carbon) and its minimum removal capacity was 105 mole g-1 (dry weight of organic carbon). Antimony removal rate of the OC material decreases from 8.2 to 1.4 nmole day-1 g-1 (dry weight of organic carbon) and its removal capacity is 2.4 μmole g-1 (dry weight of organic carbon). The minimum removal rate of FeOC material is 13 nmole day-1 g-1 (dry weight of organic carbon) and its minimum removal capacity is 8.4 μmole g-1 (dry weight of organic carbon). The As(III) : [As(III)+As(V)] ratio increased from 1% in the influent to 50% at 5.5 cm from the influent end, and to 80% at 15.5 cm from the influent end of the OC column. X-ray absorption near edge spectroscopy (XANES) shows As(III)-sulfide species on solid samples. These results suggest that As(V) is reduced to As(III) both in pore water and precipitate as As sulfides or coprecipitate with iron sulfides. The arsenic reduction rate suggests that As(V) reduction is mediated by bacterial activity in the OC column and that both abiotic reduction and bacterial reduction could be important in FeOC.

I det svenska samhället tillför diffusa och direkta föroreningskällor metaller till avloppsreningsverk, metaller som sedan hamnar i avloppsslam och recipient. Avloppsslam innehåller höga halter av växtnäringsämnen som bör återföras till jordbruksmark, men om detta ska ske får inte metallhalterna i slammet vara för höga. REVAQ är ett certifieringssystem vars syfte är att utveckla och systematisera avloppsreningsverkens uppströmsarbete och därmed möjliggöra en återföring av det växtnäringsrika slammet till jordbruksmark. Flera REVAQ-certifierade avloppsreningsverk prioriterar antimon, guld, kadmium, silver och vismut i uppströmsarbete på grund av att ackumulationshastigheten för dessa spårelement är hög i jordbruksmark som gödslas med avloppsreningsverkens slam. Source Finder (SoFi) är ett verktyg som kan användas vid uppströmsarbete för att kvantifiera identifierade källor till utsläpp av kadmium, koppar, krom, kvicksilver och zink. Syftet med examensarbetet var att vidareutveckla och anpassa verktyget SoFi till att göra beräkningar på spårelementen antimon, guld, silver och vismut samt att utveckla källan hushåll så att emissioner inom hushåll kartläggs för spårelementen och kadmium. Källor till spårelementen i avloppssystem identifierades genom litteratur och schablonvärden bestämdes för de källor det var möjligt. För att testa verktyget och kontrollera dess säkerhet utfördes en fallstudie över Käppalaverkets upptagningsområde samt en resultatkontroll. Resultaten visade att verktyget uppskattar mängden kadmium som inkommer till avloppsreningsverk bra och att inkommande mängder av antimon, silver och vismut underskattas stort. För antimon, silver och vismut var det inte möjligt att kvantifiera alla identifierade källor på grund av att kunskapen om emissioner av spårelementen är bristfällig. För guld kunde inga emissioner kvantifieras och därför beräknades inte spårelementet i verktyget. På grund av att alla stora källor inte har kvantifierats går det inte att avgöra huruvida identifieringen av källor har lyckats. Verktyget kan användas vid uppströmsarbete redan idag men genom att kvantifiera flera av de identifierade källorna kan verktyget göra större nytta och för att möjliggöra detta krävs nya studier. / Metals are transported to wastewater treatment plants (WWTPs) from diffuse and point sources in the Swedish society, these metals will end up in sewage sludge or receiving water. Sewage sludge contains a lot of plant nutrients, like phosphorus and nitrogen, which should be returned to arable land. But sludge also contains metals and if the metal content is too high the sewage sludge cannot be returned to the arable land. REVAQ is a certification system and the objective with it is to develop and systematize the WWTPs work to improve the wastewater and by that enable the return of plant nutrients to arable land. The accumulation rate of antimony, gold, cadmium, silver and bismuth are high in arable land fertilized by sewage sludge and because of that these trace elements are prioritized in WWTPs, certified by REVAQ, work to improve wastewater. Source Finder (SoFi) is a tool that can be used by the WWTPs to quantify emissions of cadmium, copper, chrome, mercury and zink from identified sources. The objectives of this master thesis were to develop and adapt the tool SoFi to estimate the trace elements antimony, gold, silver and bismuth and to develop the source household by survey the emissions of the trace elements and cadmium in it. Sources of the trace elements in the sewage system were identified by literature and emission coefficients were compiled for those sources that were possible. The new version of Source Finder was tested in the municipal WWTP Käppala and an estimation of the reasonableness of the results was made. The results showed that a good estimation of cadmium flow is made by the tool and that antimony, silver and bismuth flows are underestimated. It was not possible to determine emission coefficients for all identified sources to antimony, silver and bismuth because of the lack of knowledge about these trace elements. No emissions of gold could be quantified and the trace element was therefore not calculated by the tool. Since all identified sources have not been quantified it is not possible to determine whether all sources have been identified or not. The tool is ready to be used by the WWTPs in their work to improve the wastewater, though by quantifying further identified sources the tool will be of better use. To make that possible new studies have to be done. / Flödesanalys av spårelement från källa till slam