• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.19-28
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• 2009

The acid mine drainage (AMD) and landfill leachates released into the subsurface environment can result in serious environmental problems like soil and groundwater contamination. The AMD and the leachates of landfill were known to contain many heavy metals. In this study, the author assessed the reactivity and ability of the FeS coated-ALC for the removal of contaminants (As, Cd, Cu, Pb, Ni, Zn, Al) in AMD and leachates in landfill. The synthetic nano-FeS and Autoclaved Lightweight Concrete (ALC) were used as reactive materials in the permeable reactive barriers(PRBs). The result of batch test indicated that synthetic nano-FeS can remove 99% of heavy metals for the 1hr of reaction time except for As and Ni(about 90%). However, the 80% of As and Ni was removed in column 1(FeS coated-ALC). The column 2(Ore FeS) removed more than 99% of heavy metals. The pH of the column 1 was increased from 3.51 to 6.39~6.50, and the pH with column 2 was increased from 3.51 to 9.20. As the result of this study, the author can surmise that the synthetic nano-FeS coated ALC will use as a very good reactive material of the PRBs to treat the contaminated groundwater with AMD and leachate of landfill.

• Economic and Environmental Geology
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• v.49 no.3
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• pp.167-179
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• 2016

Water quality of Oseepchun, Dogye area, was investigated quantitatively for its origin and hydrogeochemistry in relation to the influence of groundwater. Groundwater appears to be the principal source of Oseepchun from the water-quality monitoring data including redox potentials, composition of dissolved ions and their correlations, hydrogen and oxygen stable isotopic ratios, and the distribution and occurrence of contaminants. Water-quality type of the surface water was grouped by the water-rock interactions as $Ca-HCO_3$ type originated from carbonated bed-rocks in the Joseon Supergroup, (Ca, Mg)-$SO_4$ type related with dissolution of surfide minerals in coal beds of Pyeongan Supergroup, and (Ca, Mg)-($HCO_3$, $SO_4$) type of the mixed one. Locally water pollution occurs by high $SO_4$ from mine drainage and $NO_3$ from waste-treatment facility. Intensive precipitation in summer has no effect on the water type of Oseepchun, but increases the inflow of nitrate and chloride originated from land surface. Results of this study direct that groundwater-surface water interaction is intimate, and thus surface-water resource management should begin with groundwater characterization.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.2
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• pp.107-115
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• 2023

Cobalt can be released into the natural environment as industrial waste from the alloying industry and as acid mine drainage, and it is also a radionuclide (⁶⁰Co) that constitutes high-level radioactive waste. Smectite is a mineral that can be useful for adsorption and isolation of this element. In this study, Cheto-type montmorillonite (Cheto-MM), which is the source clays of The Clay Mineral Society (CMS) and already well-characterized, was used. The effect of the adsorption site affected by the presence of interlayer water on the adsorption of cobalt before and after dehydration by heating was evaluated and the adsorption mechanism of cobalt on Cheto-MM was studied by applying adsorption kinetics and adsorption isotherm models. The results showed that the adsorption characteristics changed with dehydration and subsequent shrinkage, and cobalt was found to be adsorbed at the edge of Cheto-MM for about 38% and adsorbed at the interlayer site for about 62%, suggesting that the cobalt adsorption of Cheto-MM is significantly influenced by the interlayer. By applying the adsorption kinetic models, the cobalt adsorption kinetics of Cheto-MM is explained by a pseudo-second-order model, and the concentration-dependent adsorption was best described by the Langmuir isotherm adsorption model. This study provides basic knowledge on the adsorption characteristic of cobalt on montmorillonite with different adsorption sites and is expected to be useful in predicting the adsorption behavior of smectite in high-level radioactive waste disposal sites in the future.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.2
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• pp.95-106
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• 2021

The SO₄ in the jarosite structure can be substituted by other oxyanions, and therefore, the transition of jarosite to goethite plays a very important role in controlling the behavior of oxyanions. In this study, the phase change according to the species of the oxyanion in jarosite and the related behavior of the oxyanion was studied by mineralogical and geochemical methods when jarosite, which is coprecipitated with various oxynions, undergoes a phase change by a reductive dissolution. Jarosite substituted by five oxyanions by 5 mol% was used in this study. The mineral phase change induced by reductive dissolution using ammonium oxalate was investigated, and the order of phase transition rate of jarosite to goethite was MoO₄-jarosite ≥ SeO₄-jarosite ≥ CrO₄-jarosite > pure jarosite > SeO₃-jarosite > AsO₄-jarosite, showing that the transition rates vary depending on the substituted oxyanion. The resultant concentration of the leached Fe was slightly different depending on the type of oxyanion and time but did not show a noticeable difference. The concentration of each oxyanion leached according to the change of the mineral phase showed that the order of concentration of oxyanions was Mo > Se(SeO₃) > As > Se(SeO₄) > Cr in general, and showed a slight increase with time. This trend was related to the species of oxyanions rather than mineral phase change. The results of this study showed that the phase transition of jarosite to goethite was affected by the species of oxyanions, but this tendency did not affect the concentrations leached oxyanions.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.301-310
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• 2023

Ferrihydrite is an iron oxide mineral that is easily found in the natural environment, including acid mine drainage, and has a low crystallinity and high specific surface area, resulting in high reactivity with other ions, and can remove environmentally hazardous substances. However, because ferrihydrite is a metastable mineral, there is a possibility of releasing adsorbed ions by phase transformation to other minerals having low surface area and high crystallinity. In this study, the adsorption characteristics of arsenate, chromate, and selenate on ferrihydrite and the oxyanion removal efficiency of ferrihydrite were studied considering mineral phase transformation. At both pH 4 and 8, the adsorption of oxyanions used in the study were in good agreement with both Langmuir and Freundlich adsorption models except for selenate at pH 8. Due to the difference in surface charge according to pH, at pH 4 a higher amount of ions were adsorbed than at pH 8. The adsorption amount were in the order of arsenate, chromate, and selenate. These different adsorption models and adsorption amounts were due to different adsorption mechanisms for each oxyanions on the surface of ferrihydrite. These adsorption characteristics were closely related to changes in the mineral phase. At pH 4, a phase transformation to goethite or hematite was observed, but only a phase transformation to hematite was observed at pH 8. Among the oxyanion species on ferrihydrite, arsenate showed the highest adsorption capacity and hardly caused phase transformation during the experimental period after adsorption. Contrary to this, chromate and selenate showed faster mineral phase transformation than arsenate, and selenate had the lowest retardation effect among the three oxyanions. Ferrihydrite can effectively remove arsenate due to its high adsorption capacity and low phase transformation rate. However, the removal efficiency for other two oxyanions were low by the low adsorption amount and additional mineral phase transformation. For chromate, the efficient removal is expected only at low concentrations in low pH environments.