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Author Klimkova, S.; Cernik, M.; Lacinova, L.; Filip, J.; Jancik, D.; Zboril, R.
Title Zero-valent iron nanoparticles in treatment of acid mine water from in situ uranium leaching Type Journal Article
Year (up) 2011 Publication Chemosphere Abbreviated Journal
Volume 82 Issue 8 Pages 1178-1184
Keywords Acid mine water, Contaminant removal, Surface stabilizing shell, Water treatment, Zero-valent iron nanoparticles
Abstract Acid mine water from in situ chemical leaching of uranium (Straz pod Ralskem, Czech Republic) was treated in laboratory scale experiments by zero-valent iron nanoparticles (nZVI). For the first time, nZVI were applied for the treatment of the real acid water system containing the miscellaneous mixture of pollutants, where the various removal mechanisms occur simultaneously. Toxicity of the treated saline acid water is caused by major contaminants represented by aluminum and sulphates in a high concentration, as well as by microcontaminants like As, Be, Cd, Cr, Cu, Ni, U, V, and Zn. Laboratory batch experiments proved a significant decrease in concentrations of all the monitored pollutants due to an increase in pH and a decrease in oxidation–reduction potential related to an application of nZVI. The assumed mechanisms of contaminants removal include precipitation of cations in a lower oxidation state, precipitation caused by a simple pH increase and co-precipitation with the formed iron oxyhydroxides. The possibility to control the reaction kinetics through the nature of the surface stabilizing shell (polymer vs. FeO nanolayer) is discussed as an important practical aspect.
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ISSN 0045-6535 ISBN Medium
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Call Number THL @ christoph.kuells @ klimkova_zero-valent_2011 Serial 196
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Author Hu, K.; Wang, Q.; Tao, G.; Wang, A.; Ding, D.
Title Experimental Study on Restoration of Polluted Groundwater from in Situ Leaching Uranium Mining with Sulfate Reducing Bacteria and ZVI-SRB Type Journal Article
Year (up) 2011 Publication Procedia Earth and Planetary Science Abbreviated Journal
Volume 2 Issue Pages 150-155
Keywords In situ leaching of uranium, nitrate radical, sulfate radical, Sulfate-Reducing Bacteria (SRB), Zero Valent Iron (ZVI)
Abstract In the case of in situ leaching of uranium, the primitive geochemical environment for groundwater is changed since leachant is injected into the water beaving uranium deposit. This increases the concentration of uranium and results in the groundwater contamination.Microbial reduction technology by Sulfate reducing bacteria and Zero Valent Iron were employed to treat uranium wastewater. The experiments were conducted to evaluate the influence of anion (sulfate and nitrate) on dealing with uranium wastewater. Experimental results show that the utilization of both SRB system and ZVI – SRB system to process uranium wastewater is affected by sulfate ion and nitrate ion. As the concentration of sulfate radical is lower than 4000mg/L, sulfate-reducing bacteria has no influence on precipitated uranium. However, as the concentration of sulfate is more than 6,000mg/L, uranium removal rate decreases significantly, from 80% to 14.1%. When adding sulfate radical on ZVI – SRB system to process uranium wastewater, its uranium removal rate is higher than SRB system. Low concentration of nitrate contributes to reduction metabolism of SRB. High concentration of nitrate inhibits the growth and metabolism of SRB and affects the treatment efficiency of uranium wastewater. When the concentration of nitrate reaches 1500mg/L, uranium removal rate is less than 0.1%. Nevertheless, as the concentration of nitrate is lower than 1000mg/L, uranium removal rate could reach more than 75%. As existence of nitrate radical, uranium removal rate of SRB by adding ZVI is higher than that without adding.
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ISSN 1878-5220 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ hu_experimental_2011 Serial 202
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Author Garvelmann, J.; Külls, C.; Weiler, M.
Title A porewater-based stable isotope approach for the investigation of subsurface hydrological processes Type Journal Article
Year (up) 2012 Publication Hydrology & Earth System Sciences Abbreviated Journal
Volume 16 Issue 2 Pages
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Call Number THL @ christoph.kuells @ Garvelmann2012porewater Serial 24
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Author Stone, A.
Title Recharge investigations above the Stampriet Aquifer in semi-arid Namibia using geochemical methods and environmental tracers; sand, salt and water Type Journal Article
Year (up) 2012 Publication Quaternary International Abbreviated Journal
Volume 279-280 Issue Pages 470-471
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ISSN 1040-6182 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ stone_recharge_2012 Serial 108
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Author Pereira, A.J.S.C.; Neves, L.J.P.F.
Title Estimation of the radiological background and dose assessment in areas with naturally occurring uranium geochemical anomalies—a case study in the Iberian Massif (Central Portugal) Type Journal Article
Year (up) 2012 Publication Journal of Environmental Radioactivity Abbreviated Journal
Volume 112 Issue Pages 96-107
Keywords Background, Dose assessment, Geochemical anomalies, Mine remediation, Natural radioactivity, Uranium
Abstract Naturally occurring uranium geochemical anomalies, representative of the several thousand recognized in the Portuguese section of the Iberian Massif and outcropping in three target areas with a total of a few thousand square metres, were subjected to a detailed study (1:1000 scale) to evaluate the radiological health-risk on the basis of a dose assessment. To reach this goal some radioactive isotopes from the uranium, thorium and potassium radioactive series were measured in 52 samples taken from different environmental compartments: soils, stream sediments, water, foodstuff (vegetables) and air; external radiation was also measured through a square grid of 10×10m, with a total of 336 measurements. The results show that some radioisotopes have high activities in all the environmental compartments as well as a large variability, namely for those of the uranium decay chain, which is a common situation in the regional geological setting. Isotopic disequilibrium is also common and led to an enrichment of several isotopes in the different pathways, as is the case of 226Ra; maximum values of 1.76BqL−1 (water), 986Bqkg−1 (soils) and 18.9Bqkg−1 (in a turnip sample) were measured. On the basis of a realistic scenario combined with the experimental data, the effective dose from exposure to ionizing radiation for two groups of the population (rural and urban) was calculated; the effective dose is variable between 8.0 and 9.5mSvyear−1, which is 3–4 times higher than the world average. Thus, the radiological health-risk for these populations could be significant and the studied uranium anomalies must be taken into account in the assessment of the geochemical background. The estimated effective dose can also be used as typical of the background of the Beiras uranium metalogenetic province and therefore as a “benchmark” in the remediation of the old uranium mining sites.
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ISSN 0265-931x ISBN Medium
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Call Number THL @ christoph.kuells @ pereira_estimation_2012 Serial 129
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