| 1. |
- Björklund, Karin, 1979, et al.
(författare)
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Adsorption of Organic Pollutants in Stormwater: Evaluation of Four Potential Sorbents
- 2014
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Ingår i: Proceedings of the 13th International Conference on Urban Drainage.
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Konferensbidrag (refereegranskat)abstract
- Adsorption filters is one of the most promising techniques for removal of dissolved, colloidal and particulate pollutants from stormwater. The aim of this study was to compare the capacity of four filter materials – zeolite, cellulose, polypropylene/polyethylene (PP/PE) fibres and pine bark – to adsorb organic pollutants frequently detected in stormwater. In batch tests, synthetic stormwater spiked with polycyclic aromatic hydrocarbons (PAHs), alkylphenols and phthalates was contacted with media for up to 24 h. The compounds were then liquid-liquid extracted and analyzed using GC-MS. Zeolite and cellulose showed very low sorption capacity for the organic contaminants, whereas >70% of the initial concentration of all tested compounds was removed using PP/PE fibres, and >80% with pine bark. The highest adsorption capacity was found for PAHs (up to 44 µg/g) using PP/PE fibres and bark. For all tested compounds, maximum adsorption was approached within 30 min using these materials. Future research using natural stormwater should investigate the effect of colloidal transport of pollutants through PP/PE fibres and pine bark and the materials’ capacities to adsorb other pollutants, including metals.
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| 2. |
- Björklund, Karin, 1979, et al.
(författare)
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Adsorption of Organic Stormwater Pollutants onto Activated Carbon from Sewage Sludge
- 2017
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 197, s. 490-497
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption filters have the potential to retain suspended pollutants physically, as well as attracting andchemically attaching dissolved compounds onto the adsorbent. This study investigated the adsorption ofeight hydrophobic organic compounds (HOCs) frequently detected in stormwater e including fourpolycyclic aromatic hydrocarbons (PAHs), two phthalates and two alkylphenols e onto activated carbonproduced from domestic sewage sludge. Adsorption was studied using batch tests. Kinetic studiesindicated that bulk adsorption of HOCs occurred within 10 min. Sludge-based activated carbon (SBAC)was as efficient as tested commercial carbons for adsorbing HOCs; adsorption capacities ranged from 70to 2800 mg/g (Cinitial ¼ 10e300 mg/L; 15 mg SBAC in 150 mL solution; 24 h contact time) for each HOC. Inthe batch tests, the adsorption capacity was generally negatively correlated to the compounds' hydrophobicity(log Kow) and positively associated with decreasing molecule size, suggesting that molecularsieving limited adsorption. However, in repeated adsorption tests, where competition between HOCs wasmore likely to occur, adsorbed pollutant loads exhibited strong positive correlation with log Kow. Sewagesludge as a carbon source for activated carbon has great potential as a sustainable alternative for sludgewaste management practices and production of a high-capacity adsorption material.
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| 3. |
- Björklund, Karin, 1979, et al.
(författare)
-
Evaluation of low-cost media for sorption of organic pollutants in stormwater
- 2014
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Ingår i: World Environmental & Water Resources Congress 2014, Portland OR, USA, June 1-5, 2014.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Recent studies have shown that many organic compounds, including polycyclic aromatic hydrocarbons (PAHs) emitted through combustion and via petroleum sources, phthalate plasticizers and plastic additives such as alkylphenols, are found in stormwater at levels that exceed national and international water quality standards. This calls for efficient mitigation practices to reduce and eventually terminate the emission of these pollutants into stormwater and aquatic environments. Filtration of stormwater is one of the most promising technologies to remove particulate, colloidal and dissolved contaminants, provided that effective filtration and sorption materials are used. The aim of this research was to use laboratory-based experiments to determine the removal capacity of some selected sorbents for organic pollutants. A variety of materials previously used for metal and oil sorption, including minerals, wood- and bark-based media, were examined in 24 h batch tests using synthetic stormwater, spiked with humic acids (representing dissolved organic matter) and seven different organic pollutants. The samples were then centrifuged and filtered, liquid-liquid extracted, and analyzed using gas chromatography-mass spectrometry. As expected, the sorption tests showed that the minerals were ineffective for removing organic pollutants from stormwater. Despite its high water absorption capacity, cellulose sorbed organic contaminants only to a moderate degree. The bark-based media, however, were efficient sorbents. In general, the PAHs (90-95% of initial concentration removed) were more efficiently sorbed than alkylphenols (85-90%) and phthalates (75-85%) by bark. The results can be used as a guide in the selection of effective sorbents for the treatment of polluted stormwater in, for example, manhole filters, swales and rain gardens.
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| 4. |
- Björklund, Karin, 1979, et al.
(författare)
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Mineral Adsorbents for Removal of Metals in Urban Runoff
- 2014
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Ingår i: European Geosciences Union General Assembly 2014.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this research was to determine the capacity of four different soil minerals to adsorb metals frequently detected in urban runoff. These are low-cost, natural and commercially available soil minerals. Contaminated surface runoff from urban areas is a major cause of concern for water quality and aquatic ecosystems worldwide. Pollution in urban areas is generated by a wide array of non-point sources, including vehicular transportation and building materials. Some of the most frequently detected pollutants in urban runoff are metals. Exhaust gases, tire wear and brake linings are major sources of such metals as Pb, Zn and Cu, while impregnated wood, plastics and galvanized surfaces may release As, Cd, Cr and Zn. Many metals have toxic effects on aquatic plants and animals, depending on metal speciation and bioavailability. The removal efficiency of pollutants in stormwater depends on treatment practices and on the properties the pollutant. The distribution of metals in urban runoff has shown, for example, that Pb is predominantly particle-associated, whereas Zn and Cd are present mainly in dissolved form. Many metals are also attached to colloids, which may act as carriers for contaminants, thereby facilitating their transport through conventional water treatment processes. Filtration of stormwater is one of the most promising techniques for removal of particulates, colloidal and truly dissolved pollutants, provided that effective filtration and adsorption media are used. Filtration and infiltration are used in a wide array of stormwater treatment methods e.g. porous paving, infiltration drains and rain gardens. Several soil minerals were investigated for their potential as stormwater filter materials. Laboratory batch tests were conducted to determine the adsorption capacity of these minerals. A synthetic stormwater was tested, with spiked concentrations corresponding to levels reported in urban runoff, ranging from 50–1,500 µg/L for Zn; 5–250 µg/L for Cu, 2–20 µg/L for Cd and 10–150 µg/L for Ni and Pb. Humic acids were used to imitate natural stormwater contaminated with natural organic matter (NOM). The adsorption kinetics was also investigated through a sequence (10–120 min) of batch tests. By studying the capacity of a range of sorbents in batch tests under identical conditions, the most promising sorbent can be identified. The research is ongoing. Preliminary results will be presented.
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| 5. |
- Björklund, Karin, 1979, et al.
(författare)
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Removal of organic contaminants in bioretention medium amended with activated carbon from sewage sludge
- 2017
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 24:23, s. 19167-19180
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Tidskriftsartikel (refereegranskat)abstract
- Bioretention, also known as rain garden, allows stormwater to soak into the ground through a soil-based medium, leading to removal of particulate and dissolved pollutants and reduced peak flows. Although soil organic matter (SOM) is efficient at sorbing many pollutants, amending the bioretention medium with highly effective adsorbents has been proposed to optimize pollutant removal and extend bioretention lifetime. The aim of this research was to investigate whether soil amended with activated carbon produced from sewage sludge increases the efficiency to remove hydrophobic organic compounds frequently detected in stormwater, compared to non-amended soil. Three lab-scale columns (520 cm3) were packed with soil (bulk density 1.22 g/cm3); activated carbon (0.5% w/w) was added to two of the columns. During 28 days, synthetic stormwater—ultrapure water spiked with seven hydrophobic organic pollutants and dissolved organic matter in the form of humic acids—was passed through the column beds using upward flow (45 mm/h). Pollutant concentrations in effluent water (collected every 12 h) and polluted soils, as well as desorbed amounts of pollutants from soils were determined using GC-MS. Compared to SOM, the activated carbon exhibited a significantly higher adsorption capacity for tested pollutants. The amended soil was most efficient for removing moderately hydrophobic compounds (log Kow 4.0–4.4): as little as 0.5% (w/w), carbon addition may extend bioretention medium lifetime by approximately 10–20 years before saturation of these pollutants occurs. The column tests also indicated that released SOM sorb onto activated carbon, which may lead to early saturation of sorption sites on the carbon surface. The desorption test revealed that the pollutants are generally strongly sorbed to the soil particles, indicating low bioavailability and limited biodegradation.
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| 6. |
- Björklund, Karin, 1979, et al.
(författare)
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Sorption of DOM and hydrophobic organic compounds onto sewage-based activated carbon
- 2016
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 74:4, s. 852-860
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Tidskriftsartikel (refereegranskat)abstract
- Treatment of stormwater via sorption has the potential to remove both colloidal and dissolved pollutants. Previous research shows that activated carbon produced from sewage sludge is very efficient in sorbing hydrophobic organic compounds (HOCs), frequently detected in stormwater. The aim of this research was to determine whether the presence of dissolved organic matter (DOM) has a negative effect on the adsorption of HOCs onto sludge-based activated carbon (SBAC) in batch adsorption tests. Batch adsorption tests were used to investigate the influence of two types of DOM – soil organic matter and humic acid (HA) technical standard – on the sorption of HOCs onto SBAC, and whether preloading adsorbent and adsorbates with DOM affects HOC sorption. The results indicate that soil DOM and HAs do not have a significant negative effect on the adsorption of HOCs under tested experimental conditions, except for a highly hydrophobic compound. In addition, preloading SBAC or HOCs with DOM did not lead to lower adsorption of HOCs. Batch adsorption tests appear to be inefficient for investigating DOM effects on HOC adsorption, as saturating the carbon is difficult because of high SBAC adsorption capacity and low HOC solubility, so that limited competition occurs on the sorbent.
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| 7. |
- Björklund, Karin, 1979, et al.
(författare)
-
Sorption of organic contaminants and nutrients onto rain garden soil amended with activated carbon
- 2017
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Ingår i: Conference Proceedings, 14th IWA/IAHR International Conference on Urban Drainage; September 10-15, 2017; Prague, Czech Republic. ; , s. 1060-1064
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Konferensbidrag (refereegranskat)abstract
- Raingardens may improve stormwater quality e.g. through pollutant sorption to soil. The aimof this study was to determine if adding activated carbon, a highly efficient sorbent, to rain garden soil can enhance the removal of organic pollutants and nutrients. Batch tests show that the activated carbon is efficient in sorbing hydrophobic organic pollutants, nitrate and phosphate. However, only the organic pollutants are removed in column tests where the activated carbon is mixed with soil. The low adsorption of nutrients in column experiments is likely due to competition for adsorption sites on the carbon surface with organic matter leached from the soil.
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| 8. |
- Björklund, Karin, 1979, et al.
(författare)
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Sorption of organic pollutants frequently detected in stormwater: evaluation of five potential sorbents
- 2018
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Ingår i: Environmental Technology (United Kingdom). - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 39:18, s. 2335-2345
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption filtration is one of the most promising techniques for removal of dissolved, colloidal and particulate pollutants from stormwater. The aim of this study was to compare the capacity of five filter materials – cellulose, chitosan, chitosan-covered bark, pine bark and polypropylene/polyethylene (PP/PE) fibres – to sorb organic pollutants frequently detected in stormwater, including polycyclic aromatic hydrocarbons (PAHs), alkylphenols and phthalates. In batch tests, synthetic stormwater spiked with a mixture of the organic compounds was contacted with the materials for up to 24 h. The compounds were then liquid–liquid extracted and analysed using GC-MS. Cellulose and chitosan showed very low sorption capacity for the organic contaminants, whereas >70% of the initial concentration of most tested compounds was removed using PP/PE fibres, and >80% with pine bark and chitosan-covered bark. The highest adsorption capacity was found for PAHs (up to 44 μg/g) using PP/PE fibres and bark. For all tested compounds, maximum sorption was approached within 30 min using these materials.
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| 9. |
- Chen, Hongxia, et al.
(författare)
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PRL2 Phosphatase Promotes Oncogenic KIT Signaling in Leukemia Cells through Modulating CBL Phosphorylation
- 2024
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Ingår i: Molecular Cancer Research. - 1541-7786. ; 22:1, s. 94-103
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Tidskriftsartikel (refereegranskat)abstract
- Receptor tyrosine kinase KIT is frequently activated in acute myeloid leukemia (AML). While high PRL2 (PTP4A2) expression is correlated with activation of SCF/KIT signaling in AML, the underlying mechanisms are not fully understood. We discovered that inhibition of PRL2 significantly reduces the burden of oncogenic KIT-driven leukemia and extends leukemic mice survival. PRL2 enhances oncogenic KIT signaling in leukemia cells, promoting their proliferation and survival. We found that PRL2 dephosphorylates CBL at tyrosine 371 and inhibits its activity toward KIT, leading to decreased KIT ubiquitination and enhanced AKT and ERK signaling in leukemia cells.
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