| 1. |
- Carabante, Ivan, et al.
(författare)
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Reciprocal influence of arsenic and iron on the long-term immobilization of arsenic in contaminated soils
- 2018
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Ingår i: Environmental Arsenic in a Changing World. - London : Taylor & Francis. ; , s. 467-469
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Konferensbidrag (refereegranskat)abstract
- The main aim of this work was to evaluate the fate of arsenic associated with iron minerals in contaminated soils. The ageing behavior of synthetic arsenic-bearing poorly crystalline minerals – ferrihydrite and schwertmannite – was studied. Arsenic showed a passivation effect on poorly crystalline minerals, delaying their transformation towards more crystalline iron oxides. These results agreed well with studies performed on contaminated soils and sediments. These results are relevant in order to understand the long-term mobility of arsenic in contaminated soils and sediments. Iron oxides sequesters arsenic efficiently and, reciprocally, arsenic stabilize the mineral, delaying its transformation towards more crystalline phases.
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| 2. |
- Garcia, Gustavo, et al.
(författare)
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Preparation of zeolite A with excellent optical properties from clay
- 2015
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 619, s. 771-777
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Tidskriftsartikel (refereegranskat)abstract
- Discoloration of zeolite A powder is a common problem when natural raw materials such as kaolin clay are used because of the formation of colored iron compounds. In this study, we report on a novel method to produce zeolite A with excellent optical properties, from clays. The brightness is as high as 94.5 and the yellowness is as low as 3.0. The product is comprised of intergrown zeolite A crystals with cubic habit and a length ranging between 0.5 and 2 μm. Good optical properties are obtained when the raw material contains magnesium, as some natural raw materials do, or alternatively, when a magnesium compound is added to the raw material. Magnesium probably forces iron inside colorless extraneous magnesium aluminosilicate compounds. This simple process appears very promising for the preparation of zeolite A with good optical properties from inexpensive natural raw materials.
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| 3. |
- Kasiuliene, Alfreda, et al.
(författare)
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Hydrothermal carbonisation of peat-based spent sorbents loaded with metal(loid)s
- 2019
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Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 26:23, s. 23730-23738
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Tidskriftsartikel (refereegranskat)abstract
- Hydrothermal carbonisation (HTC) is a wet and relatively low-temperature process where, under autogenous pressures, biomass undergoes a chain of reactions leading to the defragmentation of organic matter. As well as its other uses (e.g. for producing low-cost carbon-based nano-compounds), HTC is utilised for the treatment of wet wastes, such as manure and biosludge. This study aimed to determine if hydrothermal carbonisation is a feasible treatment method for spent sorbents that are highly enriched with arsenic, chromium, copper, and zinc. The chemical properties of hydrochar and process liquid were evaluated after HTC treatment, where peat-based spent sorbents were carbonised at 230 °C for 3 h. Analysis of Fourier transform-infrared spectra revealed that during HTC, the oxygenated bonds of ethers, esters, and carboxylic groups were cleaved, and low-molecular-weight organic fragments were dissolved in the process liquid. A large fraction of arsenic (up to 62%), copper (up to 25%), and zinc (up to 36%) were transferred from the solids into the process water. Leaching of these elements from the hydrochars increased significantly in comparison with the spent sorbents.
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| 4. |
- Kasiuliene, Alfreda, et al.
(författare)
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Iron coated peat as a sorbent for the simultaneous removal of arsenic and metals from contaminated water
- 2018
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Ingår i: Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018. - London : CRC Press/Balkema. - 9781138486096 ; , s. 439-440, s. 439-440
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Konferensbidrag (refereegranskat)abstract
- This study aimed at combining peat, an industrial residue, with Fe(II)-Fe(III) compound to produce a sorbent suitable for a simultaneous removal of arsenic (As) and metals (cadmium, copper, nickel, lead, zinc) from a contaminated water. Using a newly produced sorbent – iron-peat – the removal of As from contaminated water was almost 17 times higher than using an uncoated peat. On the other hand, the removal of metals by the iron-peat was slightly less efficient in comparison to the uncoated peat. Simultaneous removal of As and metals could be seen as an advantage over multiple-step treatment of contaminated groundwater.
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| 5. |
- Kasiuliene, Alfreda
(författare)
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Peat Coated with Iron Oxides : Purification of Metal(loid)-Contaminated Water and Treatment of the Spent Adsorbent
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden due to the industrial activities, such as wood impregnation, multiple point sources of arsenic (As) contamination in soil and water bodies are scattered over the country. Metals, such as chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), cadmium (Cd) or zinc (Zn) at varying concentrations are usually present as well. Since adsorption is a common method to purify contaminated water, research and development of adsorbents have been actively carried out in the last few decades. However, seldom spent sorbent is safely handled afterwards and often end up in landfill, thus creating new problems and posing new risks to humans and environment.The aim of this study was to develop a waste-based adsorbent for simultaneous removal of As and associated metals: Cr, Cu and Zn, and to analyse sustainable ways how to manage the spent adsorbent without creating secondary pollution.In the model system two well-establish adsorbents: Fe oxides (deriving from FeCl3) and peat (waste-based), were combined and the concept of simultaneous removal of cationic and anionic contaminants was tested in a batch adsorption experiment. Due to Fe coating, removal of As and Cr increased by 80% and 30%, respectively, as compared to non-coated peat. Removal of Cu and Zn was higher (up to 15%) on non-coated peat than on Fe-coated peat. Similar results were obtained in the up-scaled column adsorption experiment, where Fe salt was substituted with a waste-based Fe hydrosol. Within the same pH environment (pH=5), Fe-coated peat effectively adsorbed all four investigated contaminants (As, Cr, Cu and Zn). Non-coated peat was effective for Cr, Cu and Zn. While, Fe oxides (coated on sand) adsorbed only As.Three management strategies for spent adsorbents, obtained after column adsorption experiment, were investigated in this study. i) Long-term deposit in a landfill was simulated by exposing spent adsorbents to a reducing environment and evaluating metal(loid) leaching. Leaching of As increased manifold (up to 60% in a 200-day experiment) as compared to the standardized batch leaching experiment under oxidizing conditions. It was determined that about one third of As(V) was reduced to As(III), which is more mobile and toxic. ii) Valorisation of the spent adsorbent was attempted through hydrothermal carbonisation. It was expected that obtained hydrochar could be used as a beneficial soil amendment. However, treatment resulted in the process liquid and the hydrochar both having high loads of As, Cu and Zn. Additional treatment of process water and hydrochar imply higher management costs for spent adsorbents. iii) Possibility of thermal destruction was investigated by combusting spent adsorbents. After the treatment volume of the waste (ash) was by 80-85% smaller as compared to spent adsorbents. Combustion at higher temperature (1100 °C vs 850 °C) resulted into a weaker metal(loid) leaching from ashes. Furthermore, co-combustion with calcium (Ca)-rich lime (waste-based) decreased leaching of all four investigated elements, Cr in particular, below the limit values for waste being accepted at landfills for hazardous waste. Therefore, combustion enabled possibility of safe and long-term deposit of As-bearing ashes. At the same time, less As would be circulating in society. For the future work, studies that could broaden the spectrum of contaminants targeted by Fe-coated peat would be beneficial. At the same time it is important not only to find alternative utilisation methods for Fe-coated peat, but also investigate other management options for the spent adsorbents.
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| 6. |
- Kasiuliene, Alfroda, et al.
(författare)
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Removal of metal(oid)s from contaminated water using iron-coated peat sorbent
- 2018
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 198, s. 290-296
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed at combining iron and peat to produce a sorbent suitable for a simultaneous removal of cations and anions from a solution. Peat powder, an industrial residue, was coated with iron by immersing peat into iron salt solutions. The adsorption efficiency of the newly produced sorbent towards As, Cr, Cu and Zn was tested by means of batch adsorption experiments at a constant pH value of 5. Coating of Fe on peat significantly increased the adsorption of As (from <5% to 80%) and Cr (from <3% to 25%) in comparison to uncoated peat. Removal of cations on coated peat slightly decreased (by 10–15%), yet remained within acceptable range. Electron Microscopy combined with X-Ray Energy Dispersive Spectroscopy revealed that iron coating on the peat was rather homogenous and As and Cr were abundantly adsorbed on the surface. By contrast, Cu and Zn displayed a sparing distribution on the surface of the iron coated peat. These results indicate that iron-peat simultaneously target sufficient amounts of both cations and anions and can be used for a one-step treatment of contaminated groundwater.
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| 7. |
- Kasiuliene, Alfreda, et al.
(författare)
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Treatment of metal (loid) contaminated solutions using iron-peat as sorbent : is landfilling a suitable management option for the spent sorbent?
- 2019
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Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 26:21, s. 21425-21436
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Tidskriftsartikel (refereegranskat)abstract
- This study firstly aimed to investigate the potential of simultaneous metal (loid) removal from metal (oid) solution through adsorption on iron-peat, where the sorbent was made from peat and Fe by-products. Up-flow columns filled with the prepared sorbent were used to treat water contaminated with As, Cu, Cr, and Zn. Peat effectively adsorbed Cr, Cu, and Zn, whereas approximately 50% of inlet As was detected in the eluent. Iron-sand was effective only for adsorbing As, but Cr, Cu, and Zn were poorly adsorbed. Only iron-peat showed the simultaneous removal of all tested metal (loid)s. Metal (loid) leaching from the spent sorbent at reducing conditions as means to assess the behaviour of the spent sorbent if landfilled was also evaluated. For this purpose, a standardised batch leaching test and leaching experiment at reducing conditions were conducted using the spent sorbent. It was found that oxidising conditions, which prevailed during the standardised batch leaching test, could have led to an underestimation of redox-sensitive As leaching. Substantially higher amounts of As were leached out from the spent sorbents at reducing atmosphere compared with oxidising one. Furthermore, reducing environment caused As(V) to be reduced into the more-toxic As (III).
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| 8. |
- Kumpiene, Jurate, et al.
(författare)
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In situ chemical stabilization of trace element-contaminated soil : Field demonstrations and barriers to transition from laboratory to the field : A review
- 2019
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Ingår i: Applied Geochemistry. - : Elsevier. - 0883-2927 .- 1872-9134. ; 100, s. 335-351
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Tidskriftsartikel (refereegranskat)abstract
- The chemical stabilization, or immobilization, of trace elements (metals and metalloids; TE) in contaminated soil has been studied for decades. A vast number of scientific publications are available on the method performance in laboratory settings, reporting that the application of various soil amendments to contaminated soil reduces TE mobility, bioavailability and toxicity. The most commonly used soil amendments include organic matter, iron oxides, phosphates, ashes, and lately biochar, alone or in combination with each other and/or lime. Most of the implemented field studies show a certain degree of improvement in soil and/or vegetation status following amendment. Regardless the positive performance of the technique in the laboratory, field validations and demonstrations remain scarce. The establishment of a field experiment often involves permits from authorities and agreements with site owners, both of which are considerably more time-consuming than laboratory tests. Due to conservative institutional structures, public authorities have been slow to adopt alternative remediation technologies, especially when the total TE concentration in soil remains the same and all of the associated risks are not yet convincingly described. For this reason, researchers should also focus on enhancing public knowledge of alternative remediation techniques so that future projects which aim to demonstrate the effectiveness of in situ immobilization techniques under natural conditions will be supported.
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| 9. |
- Kumpiene, Jurate, et al.
(författare)
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Leaching of arsenic, copper and chromium from thermally treated soil
- 2016
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 183:3, s. 460-466
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Tidskriftsartikel (refereegranskat)abstract
- Thermal treatment, if properly performed, is an effective way of destroying organic compounds in contaminated soil, while impact on co-present inorganic contaminants varies depending on the element. Leaching of trace elements in thermally treated soil can be altered by co-combusting different types of materials. This study aimed at assessing changes in mobility of As, Cr and Cu in thermally treated soil as affected by addition of industrial by-products prior to soil combustion. Contaminated soil was mixed with either waste of gypsum boards, a steel processing residue (Fe3O4), fly ash from wood and coal combustion or a steel abrasive (96.5% Fe0). The mixes and unamended soil were thermally treated at 800 °C and divided into a fine fraction <0.125 mm and a coarse fraction >0.125 mm to simulate particle separation occurring in thermal treatment plants. The impact of the treatment on element behaviour was assessed by a batch leaching test, X-ray absorption spectroscopy and dispersive X-ray spectrometry. The results suggest that thermal treatment is highly unfavourable for As contaminated soils as it increased both the As leaching in the fine particle size fraction and the mass of the fines (up to 92%). Soil amendment with Fe-containing compounds prior to the thermal treatment reduced As leaching to the levels acceptable for hazardous waste landfills, but only in the coarse fraction, which does not justify the usefulness of such treatment. Among the amendments used, gypsum most effectively reduced leaching of Cr and Cu in thermally treated soil and could be recommended for soils that do not contain As. Fly ash was the least effective amendment as it increased leaching of both Cr and As in majority of samples.
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| 10. |
- Kumpiene, Jurate, et al.
(författare)
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Remediation of soil contaminated with organic and inorganic wood impregnation chemicals by soil washing
- 2017
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 184, s. 13-19
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the efficiency of a large scale washing/wet sieving technique for a soil contaminated with wood impregnation chemicals by 1) defining the final distribution of trace elements (As, Cu, Cr, Zn) and polycyclic aromatic hydrocarbons (PAH) in separated soil particle size fractions; and 2) defining the leaching behavior of the contaminants in these soil fractions. A soil washing experiment was implemented at waste management facility in Sweden using a full scale soil sorting and washing equipment. Five tons of soil was loaded to the equipment and wet-sieved into the following fractions: >16 mm, 8–16 mm, 2–8 mm, 0.2–2 mm, <0.2 mm and a fraction that floated on top of the slurry before the final separation phase, composed of organic matter (OM). Analysis of total concentrations of contaminants in all soil fractions indicated that wet sieving/soil washing was not efficient to reduce the total volume of soil that needs further treatment. Even the coarsest soil fractions (>8 mm) contained elevated concentrations of total As and PAH. Leaching of As from all washed soil fractions was so high, that none of the particle size fractions could be disposed of without additional treatment.
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| 11. |
- Lidelöw, Sofia, et al.
(författare)
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Leaching behaviour of copper slag, construction and demolition waste and crushed rock used in a full-scale road construction
- 2017
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Ingår i: Journal of Environmental Management. - : Elsevier. - 0301-4797 .- 1095-8630. ; 204:1, s. 695-703
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Tidskriftsartikel (refereegranskat)abstract
- The leaching behaviour of a road construction with fayalitic copper slag, recycled concrete and crushed rock as sub-base materials was monitored over ten years. All studied materials used in the road construction, including crushed rock, contained concentrations of several elements exceeding the guideline values recommended by the Swedish EPA for total element concentrations for waste materials used in constructions. Despite that, leaching from the road construction under field conditions in general was relatively low. The leachates from the recycled materials contained higher concentrations of several constituents than the leachates from the reference section with crushed rock. The leaching of the elements of interest (Cr, Mo, Ni, Zn) reached peak concentrations during the second and fourth (Cu) years and decreased over the observation period to levels below the Swedish recommended values. Carbonation of the concrete aggregates caused a substantial but short-term increase in the leaching of oxyanions such as chromate. The environmental risks related to element leaching are highest at the beginning of the road life. Ageing of materials or pre-treatment through leaching is needed prior to their use in construction to avoid peak concentrations. Also, the design of road constructions should be adjusted so that recycled materials are covered with low-permeability covers, which would minimize the exposure to atmospheric precipitation and weathering.
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| 12. |
- Trublet, Mylene, et al.
(författare)
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Competitive Sorption of Metal Ions on Titanium Phosphate Sorbent(TiP1) in Fixed-Bed Columns : A Closed-Mine Waters Study
- 2019
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 7:9, s. 8145-8154
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Tidskriftsartikel (refereegranskat)abstract
- Sorptionfixed-bed column experiments were performed using atitanium phosphate ion-exchanger composed of−H2PO4units [TiO(OH)(H2PO4)·H2O]. Model mine water containingfive divalent metal ions (Cu2+,Zn2+,Mn2+,Ni2+,and Co2+) and a few closed-mine water samples were treated to evaluate the sorptionpreference of the material. For thefirst time, dynamic ion-exchange capacities(estimated to be between 3.2 and 4.2 mequiv g−1) and static ion-exchange uptakes(calculated to be between 3.1 and 3.5 mequiv g−1) were obtained for the same TiP1sorbent and data were discussed in terms of sorption behavior. It was found thatsorption processes on TiP1 in model and closed-mine waters during a columnexperiment could be accurately predicted from the corresponding batch experiment(including the sorbent’s capacities in different types of waters). A competitivesorption phenomenon in favor of Cu2+on TiP1 was established for all cases, pointingtoward the possibility of isolating pure copper concentrate from closed-mine waters.The relatively high amounts of calcium and magnesium ions present in mine waters did not appear to considerably affect theselectivity of TiP1 material. Exploratory experiments for sorbent regeneration and desorption using a low concentration of nitricacid were demonstrated.
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