| 1. |
- Boman, Anton, et al.
(författare)
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Sulfur dynamics in boreal acid sulphate soils rich in metastable iron sulfide – The role of artificial drainage
- 2008
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Ingår i: Chemical Geology. - : Elsevier BV. - 0009-2541 .- 1872-6836. ; 255:1-2, s. 68-77
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Tidskriftsartikel (refereegranskat)abstract
- The sulfur dynamics of boreal brackish-water sediments rich in metastable iron sulfide (average elemental composition of FeS1.1), which upon oxidation have a huge impact on stream-water chemistry, were studied. Two cores, extending from the upper oxidized layer (acid sulfate soil) into the underlying iron sulfide-bearing sediment (potential acid sulfate soil) were collected at a site close to the sea level and at another site about 40 m above the latter in a region of current isostatic land uplift (Finland). The data clearly show, in contrast to what is often argued, that these notorious acidic soils are formed not as a result of the natural uplift but because of extensive ditching of farmlands. Above the depth of artificial drainage, S and Ni are abundantly lost, while beneath that level pyrite is abundant and metastable iron sulfide is increasing with depth, and the Ni concentration is relatively stable. In the narrow zone between the reduced and oxidized layers, the processes are dynamic and result in preservation of elemental S at one of the locations. The sulfur isotopic composition for metastable iron sulfide and pyrite in the investigated acid sulfate soils were found to be distinctly bimodal and roughly corresponding to a similar distribution in stream-water sulfate earlier reported from the same region. This indicates that pyrite is the main source of sulfate and acidity in some affected drains, while in others it is metastable iron sulfide.
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| 2. |
- Widerlund, Anders, et al.
(författare)
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Early diagenesis and isotopic composition of lead in Lake Laisan, northern Sweden
- 2002
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Ingår i: Chemical Geology. - 0009-2541 .- 1872-6836. ; 189:3-4, s. 183-197
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Tidskriftsartikel (refereegranskat)abstract
- Water column (dissolved/suspended phase, sediment traps) and sediment data (pore-water, solid-phase sediment) were combined with stable Pb and 210Pb isotope data to trace the early diagenetic behaviour and geochemical cycling of Pb in Lake Laisan, a lake which has received large quantities of anthropogenic Pb since the early 1940s. Early diagenetic remobilisation of Pb is indicated by a subsurface pore-water Pb maximum (120 µg 1-1) in the oxic surface layer of the sediment, where the solid-phase Pb concentration is 3400-4600 µg g-1. The remobilisation of Pb appears to be caused by a pH-controlled desorption of Pb from solid-phase sediment, which is consistent with a model describing surface complexation of Pb(II) on hydrous goethite surfaces. The diffusive Pb flux from the subsurface pore-water maximum towards the sediment surface (36 µg cm-2 year -1) exceeds the depositional Pb flux (8.6 µg cm -2 year -1) by approximately a factor of four, indicating that Pb is highly mobile in the sediment. Stable Pb isotope data and a mass balance calculation suggest that Pb diffusing upwards is, to a large extent, trapped in the surface sediment. Lead that may diffuse into the slightly alkaline lake water appears to be efficiently sorbed to suspended particulate matter, resulting in low dissolved Pb concentrations in the water column (0.040-0.046 µg 1-1). Sorption of Pb to suspended particulate matter is consistent with the elevated suspended particulate Pb concentrations in the hypolimnion (3800-4000 µg g-1), and the fact that the stable Pb isotopic compositions of suspended matter and pore-water are similar. © 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
- Åström, Mats E., et al.
(författare)
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Attenuation of rare earth elements in a boreal estuary
- 2012
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 96, s. 105-119
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on attenuation of rare earth elements (REE) when a boreal creek, acidified and loaded with REE and other metals as a result of wetland drainage, empties into a brackish-water estuary (salinity < 6 parts per thousand). Surface water was collected in a transect from the creek mouth to the outer estuary, and settling (particulate) material in sediment traps moored at selected locations in the estuary. Ultrafiltration, high-resolution ICP-MS and modeling were applied on the waters, and a variety of chemical reagents were used to extract metals from the settling material. Aluminium, Fe and REE transported by the acidic creek were extensively removed in the inner/central estuary where the acidic water was neutralised, whereas Mn was relatively persistent in solution and thus redistributed to particles and deposited further down the estuary. The REE removal was caused by several contemporary mechanisms: co-precipitation with oxyhydroxides (mainly Al but also Fe), complexation with flocculating humic substances and sorption to suspended particles. Down estuary the dissolved REE pool, remaining after removal, was fractionated: the < 1 kDa pool became depleted in the middle REE and the colloidal (0.45 mu m-1 kDa) pool depleted in the middle and heavy REE. This fractionation was controlled by the removal process, such that those REE with highest affinity for the settling particles became most depleted in the remaining dissolved pool. Modeling, based on Visual MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (< 0.45 mu m) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.
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| 4. |
- Morin, Dominique, et al.
(författare)
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BioMinE : integrated project for the development of biotechnology for metal-bearing materials in Europe
- 2006
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Ingår i: Hydrometallurgy. - : Elsevier. - 0304-386X .- 1879-1158. ; 83:1-4, s. 69-76
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Tidskriftsartikel (refereegranskat)abstract
- Biohydrometallurgy is the offspring of the unexpected union of biotechnology and metallurgy. From specific properties of some extreme biotopes, active principles of interactions between microbial metabolisms and minerals have been extracted to be used as efficient metallurgical processes.Many profitable industrial operations based on these bioprocesses have been running to recover copper, gold, uranium or cobalt for instance and many other applications have been designed.Europe was quite active in this area in the past, but currently the leadership is in South Africa, America and Australia.BioMinE (Biotechnology for Metal-bearing material In Europe) is a large integrated project launched with the support of the European Commission. It is aimed at stimulating synergies between the most relevant universities, research and industrial organisations to develop new concepts in this technical field that allow a better exploitation of the mineral resources in the future.The main technical subject is the investigation of the opportunities to apply bioleach processes to primary and secondary resources of metal-bearing materials. The second technical area of the project in terms of effort is the study of the recovery of metals from pregnant bioleach solution using biological reagents. All along the project duration, these investigations are focussed on the relevant resources in Europe screened according to an iterative process. The integration of the innovative pathways of processing will be evaluated up to the pilot scale whenever it is appropriate.The Consortium of BioMinE comprises 35 partners from industry (12 including 5 SMEs) research organisations (9) universities (14) and government (2). The participants are from 12 EU member states, from 1 candidate country (Romania), and from South Africa (INCO Country).The overall budget of the project is 17.9 million Euros, with a contribution from the European Commission of 11.6 million Euros. Started on November 1, 2004, the project will last 4 years.An overview of BioMinE in the general context of the biohydrometallurgy development is the subject of this presentation.
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| 5. |
- Morin, Dominique, et al.
(författare)
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Progress after three years of BioMinE-Research and Technological Development project for a global assessment of biohydrometallurgical processes applied to European non-ferrous metal resources
- 2008
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Ingår i: Hydrometallurgy. - : Elsevier. - 0304-386X .- 1879-1158. ; 94:1-4, s. 58-68
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Tidskriftsartikel (refereegranskat)abstract
- BioMinE is an integrated project under the sixth framework programme of research supported by the European Commission, which started in November 2004 and will last until October 2008 (Ref. NMP2-CT-2005-500329). It is dedicated to the evaluation of biohydrometallurgy to improve the exploitation of the European non-ferrous metal resources in a sustainable way. At the end of 2007, the Consortium of BioMinE comprised 37 partners from industry (13 including 6 Small or Medium Enterprises), research organisations (8), universities (15), and government (1). The participants are from 13 EU member states and from Serbia and South Africa (INCO Countries). For more details see http://biomine.brgm.fr.The three main kinds of resources considered for bioleaching studies are:- Copper polymetallics (concentrates and tailings),- Zinc polymetallics (zinc and zinc polymetallic concentrates)- Secondary wastes (tailings, rock and metallurgical wastes, etc.)For each of these resources, amenability studies of application of bioleaching technologies by various approaches have been undertaken or still ongoing. Further processing assessment will be conducted up to the demonstration scale. Technological improvements have been made to apply bioleaching in the context of the European resources in terms of complexity and sustainability requirements. The relevant fundamental studies covering bio-prospecting, molecular ecology, biochemistry, and genetics areas aimed at improving the understanding and the control of the selected technologies have given original results.Much progress has also been obtained in the use of the microbial sulfate-reducing process to polish effluents and to recover metals from leachates containing low concentrations of metals. The finding of micro-organisms thriving at low and high temperature, respectively 8 and 65 °C, leads to an extension of the application range of the process. It has been also observed that this process could be pushed down to pH 4.5 and 4 creating opportunities of selective metal recovery as metal sulphides. It has also been demonstrated that sulphate can be removed at high concentrations, as well as arsenic or selenium. The next step in this work is pilot testing. This will allow to determine scale-up criteria and to assess the residual metal concentration under actual conditions.The pilot-scale demonstration operations, as well as the techno-economic and comparative sustainability assessments will be achieved during 2008, the last year of the project.The prototypes of the learning objects for training about biohydrometallurgy accessible by internet have been elaborated. A public output of this work is accessible at http://wiki.biomine.skelleftea.se/wiki. The basic knowledge thus delivered is aimed at disseminating the understanding of the origins and use of biohydrometallurgy.Contacts with mining operators in Europe have been taken and collaboration schemes have been established in various ways according to the respective contexts. When a high potential of technical involvement could be foreseen, a direct participation of the mining operators in the project was favoured, this led to integrate KGHM (Pol), Boliden (Sw) and Copper Institute of Bor (Serbia) into the consortium of partners.When no direct technical commitment was conceivable at the first stage, collaboration was established with companies with the most urgent requirement to have access to the relevant resource.
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| 6. |
- Kumpiene, Jurate, et al.
(författare)
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Phosphorus and cadmium availability in soil fertilized with biosolids and ashes
- 2016
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 151, s. 124-132
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Tidskriftsartikel (refereegranskat)abstract
- The recycling of hygienized municipal sewage sludge (biosolids) to soil as the source of phosphorus (P) is generally encouraged. The use of biosolids, however, has some concerns, such as the presence of elevated concentrations of potentially toxic trace elements, and the possible presence of pathogens, hormones and antibiotics. Organic substances are destroyed during combustion whereas trace elements could partly be separated from P in different ash fractions. Biomass combustion waste (ash) can instead be considered as an alternative P source. This study evaluates and compares the impact of biosolids and their combustion residues (ashes), when used as fertilizers, on P and Cd solubility in soil, plant growth and plant uptake of these elements. Biosolids were also amended with K and Ca to improve the composition and properties of P in ashes, and incinerated at either 800 °C or 950 °C. Combustion of biosolids improved the Cd/P ratio in ashes by 2–5 times, compared with the initial biosolids. The low Cd content in ashes (4–9 mg Cd (kg P)−1) makes this material a particularly attractive alternative to mineral fertilizers. Significantly higher pore water P (as well as total N) was measured in soils containing biosolids, but plants produced a higher biomass in soil fertilized with ashes. The K and Ca amendments prior to biosolids combustion generally decreased the total Cd in ash, but had little effect on P and Cd uptake and biomass growth. Similarly, the combustion temperature had negligible effect on these factors as well.
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| 7. |
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| 8. |
- Conrad, Sarah, et al.
(författare)
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Seasonal Variations of Redox State in Hemiboreal Soils Indicated by Changes of δ56Fe, Sulfate, and Nitrate in Headwater Streams
- 2019
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Ingår i: ACS Earth and Space Chemistry. - : American Chemical Society (ACS). - 2472-3452. ; 3:12, s. 2816-2823
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Tidskriftsartikel (refereegranskat)abstract
- During recent decades, much focus has been put on the iron (Fe) isotope ratios in soils, rivers, and oceans, while studies on the variation in headwater streams are scarce. Here we assess seasonal water chemical data from 104 hemiboreal headwater streams. Between summer and late autumn, decreasing Fe concentrations and simultaneously increasing sulfate and nitrate concentrations suggest a shift from reduced to oxidized conditions in the soils along the main groundwater flow paths. Fe isotope data, obtained from a subpopulation of 16 streams, show low δ56Fe ratios during summer drought, indicating an important influx of reduced groundwater to the streams with primarily Fe(II) as an important Fe source. In total, the δ56Fe data ranged between −0.8 ± 0.1 and 1.8 ± 0.1‰ with the lowest values in summer and maximum δ56Fe ratios in late autumn or spring, indicating an influx of more oxidized, less Fe(II) rich groundwater during those seasons. Local differences in δ56Fe ratios between the headwater streams, seemed to be driven by the different soil redox status of the catchments. The streams with the lowest δ56Fe ratios during summer are characterized by a small share (4.4 ± 6.6%) of wetlands, indicating discharge of reduced groundwater from mainly anoxic, moist, organic-rich mineral soils during drought. Relatively high total organic carbon (TOC) concentrations (2.4 ± 1.1 mM) and low pH (5.2 ± 0.8) may have restricted efficient Fe(II) oxidation in streamwater especially during the late autumn survey. Our results from hemiboreal headwater streams reveal the importance of climatic, pedogenic, and land cover-derived controls on the provenance of stream Fe loads that is likely broadly applicable to similar streams elsewhere.
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| 9. |
- Perroud, Théo, et al.
(författare)
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Testing bioplastic containing functionalised biochar
- 2022
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Ingår i: Polymer testing. - : Elsevier. - 0142-9418 .- 1873-2348. ; 113
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Tidskriftsartikel (refereegranskat)abstract
- Although flame retardants are very effective in reducing the fire hazard of polymeric materials, their presence may be detrimental to mechanical strength. Hence, in order to have a holistic improvement of performance properties, a new approach has been developed wherein biochar is used to host a naturally-occurring flame retardant (lanosol). The issue of loss in mechanical strength of a polymer host is alleviated by the use of biochar. Three different doping procedures were investigated, namely, dry mixing, and chemical and thermal-based doping, to integrate lanosol into the biochar pores. The doped biochar was used to develop wheat gluten-based blends. The mechanical and flammability properties of the blends were assessed. It was found that thermal doping was the most effective in introducing significant amounts of lanosol particles inside the biochar pores. The bioplastic containing chemically, and thermally doped biochar had equal tensile strength (5.2 MPa), which was comparable to that of the unmodified material (5.4 MPa). The thermally doped biochar displayed the lowest cone calorimeter peak heat release rate (636 kW m−2) for combustion and the highest apparent activation energy (32.4 kJ mol−1) for decomposition. Thus, for flame retarding protein-based matrices, the use of additives thermally doped into biochar is recommended to both simultaneously improve fire-resistance and conserve mechanical strength.
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| 10. |
- Ruth, Katja Viventsova, et al.
(författare)
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Changes in soil organic matter composition and quantity with distance to a nickel smelter : a case study on the Kola Peninsula, NW Russia
- 2005
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Ingår i: Geoderma. - : Elsevier BV. - 0016-7061 .- 1872-6259. ; 127:3-4, s. 216-226
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Tidskriftsartikel (refereegranskat)abstract
- The capacity of soils to absorb contamination depends on a number of factors, such as soil organic matter (SOM) that plays an essential role in adsorption of metal ions, especially in Podzols with their low content of clay minerals. Detailed analysis of SOM can provide information about the potential capacity of a soil to mobilise or immobilise contaminating substances, which in turn can be used to predict potential recovery of the soil ecosystem following heavy metal pollution. The purpose of this study was to learn how an increasing load of heavy metals (Cu and Ni) affects SOM content and structure, and which of the SOM functional groups are responsible for metal retention. The study area is located in the central part of the Kola Peninsula, south of Monchegorsk city and the nickel smelting complex ‘Severonickel’. The amount of total carbon in the soil decreased from 86% to 0.6% as the distance from the smelting complex decreased from 34 to 2 km. Functional groups of the SOM had a larger diversity in less polluted soils than in the soils located closer to the smelting complex. Carboxyl groups had a higher intensity of infra red (IR) bands in soils collected at the distance of 34–27 km than those located closer to the smelter. The most disturbed soil at the site closest to the smelter showed almost no presence of COOH groups. We conducted a laboratory experiment using soils from the least polluted sampling site to assess which SOM functional groups may be responsible for metal retention. Experimental contamination of the soil with the Cu/Ni solution resulted in an overall decrease in the absorbance for all studied functional groups within the measured range, except for COOH. This could be attributed both to changes in the structure of the SOM caused by its reaction with the contaminating substances, and to the leaching of some of the organic compounds from the soil during the experiment. Further studies are needed to better understand which functional groups in the SOM are active in the adsorption processes.
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