• Applied Chemistry for Engineering
• /
• v.10 no.1
• /
• pp.24-29
• /
• 1999

Naturally-occurring iron minerals, goethite, magnetite, and hydrogen peroxide were used to catalyze and initiate Fenton-like oxidation of silica sand contaminated with mixture of diesel and kerosene in batch system. Optimal reaction conditions were investigated by varying pH(3, 7), $H_2O_2$ concentration(0%, 1%, 7%, 15%, 35%), initial contaminant concentration(0.2, 0.5, 1.0 g-mixture of diesel and kerosene/ kg-soil), and iron mineral contents(1, 5, and 10 wt % magnetite or goethite). Contaminant degradations in silica sand-iron mineral-$H_2O_2$ systems were identified by determining total petroleum hydrocarbon(TPH) concentration. The optimal pH of the system was 3. The system which iron minerals were the only iron source was more efficient than the system with $FeSO_4$ solution due to lower $H_2O_2$ consumption. In case of initial contaminant concentration of 1g-contaminant/kg-soil with 5 wt % magnetite, addition of 0%, 1%, 7%, 15%, and 35% of $H_2O_2$ showed 0%, 24.5%, 44%, 52%, and 70% of TPH reduction in 8 days, respectively. When the mineral contents were varied 0, 1, 5, and 10wt%, removal of contaminants were 0%, 33.5%, 50%, and 60% for magnetite and 0%, 29%, 41%, and 53% for goethite, respectively. Reaction of magnetite system showed higher degradation than that of goethite system due to dissolution of iron and mixed presence of iron(II) and iron(III); however, dissolved iron precipitated on the surface of iron mineral and seemed to cause reducing electron transfer activity on the surface and quenching $H_2O_2$. The system using goethite has better treatment efficiency due to less $H_2O_2$ consumption. When cach system was mixed by shaker, removal of contaminants increased by 41% for magnetite and 30% for goethite. Results of this study showed catalyzed $H_2O_2$ system made in-situ treatment of soil contaminated with petroleum possible without addition of iron source since natural soils generally contain iron minerals such as magnetite and goethite.

• Journal of the Mineralogical Society of Korea
• /
• v.21 no.2
• /
• pp.139-159
• /
• 2008

Geochemical analysis of the various kinds of water including observation borehole groundwater was carried out for the assessment of the hydrological safety of the underground oil storage cavern and the potentiality of mineralogical and microbiological clogging was estimated. Most of water samples belonged to $Ca-HCO_3$ and $Ca-HCO_3-SO_4$ types. There was no distinct chemical difference in the various kinds of water. All kinds of water are undersaturated with the calcite which is the major clogging mineral. Most water samples have low Fe and Mn concentrations. However, they are saturated or oversaturated with the iron-oxide/hydroxide minerals and have high dissolved oxygen contents which suggests the possibility of clogging by the iron-oxide/hydroxide minerals as a long-term aspect. Several water samples from the ground observation borehole also show the high saturation indices far the clay minerals, which can fill up the fractures, indicating the possibility of clogging by the clay minerals. Statistical analysis shows the degree of mineral precipitation or dissolution is mainly controlled by pH, Eh and DO of water samples. According to the microbial analysis, the aerobic microbes and slime forming bacteria are dominant in most water samples and anaerobic microbes including sulfate reducing bacteria are very low or not detected. Although the slime forming bacteria which are known as a main microbial cause of the clogging is lower than $10^5\;CFUs/mL$ in all water samples, because the slime forming bacteria are dominant microbe in several observation boreholes, the clogging can be caused by it as a long-term aspect. In addition, the possibility of clogging can be increased if the microbial effect is combined with the mineralogical effect such as iron oxide/hydroxide minerals for the possibility of clogging. Therefore, the systematic and long-term program for the assessment of clogging is required for the safe operation of underground oil storage cavern.

• Journal of Soil and Groundwater Environment
• /
• v.10 no.1
• /
• pp.43-57
• /
• 2005

Twelve bottom sediments and three cores were collected in Juam reservoir for a study on transportation, which was controlled by particle grain size (2mm-200{\mu}m,\;200-100{\mu}m,\;100-50{\mu}m,\;50-20{\mu}m,\;<20{\mu}m), and vertical distribution of heavy metals. Sediment cores were sliced into 2 to 5 cm intervals to measure heavy metal concentrations in interstitial water and sediments with depth. Pb isotopic compositions of core samples were determined to calculate sedimentation rate. Regardless of sampling sites, levels of heavy metals and trace elements in bottom sediments are nearly constant with mean values of $14.9\;{\mu}g/g\;for\;As,\;0.81{\mu}g/g\;for\;Cd,\;30.7{\mu}g/g\;for\;Cu,\;34.7{\mu}g/g\;for\;Ni,\;63.3{\mu}g/g\;for\;Pb\;and\;87.9{\mu}g/g\;for\;Zn$. In general, Cu, Pb, Zn, Wi, and Cr in fraction of $<20{\mu}m$ exhibit the highest concentration, but content of As is the highest in grain size of $2\;mm-200\;{\mu}m$ and $200-100\;{\mu}m$. Fe and Mn occur as the dissolved compositions of the highest concentrations in interstitial waters and increase in their concentrations toward lower part of cores. On the contrary, concentrations of Zn and Cu show the highest value in the uppermost part in cores, suggesting these elements are released from reductive dissolution of hydroxides and oxidation of organic matters under different redox conditions. The highest accumulations of Cu, Ni, Pb, and Zn contents in the sediment cores are observed at 0-4 cm layers, and concentrations of Cu and Pb are especially high, implying these heavy metals are originated from anthropogenic sources. The apparent sedimentation rate estimated using unsupported $^{210}Pb$ is 0.91 cm $year^{-1}$, corresponding about 10 cm sedimentation in total depth since construction of Juam dam. These results will provide available information for management of bottom sediment in Juam reservoir.

• Korean Journal of Mineralogy and Petrology
• /
• v.33 no.1
• /
• pp.41-51
• /
• 2020

The purpose of this study was to investigate the possibility of eco-friendly/efficient recovery of valuable resources, such as Au from mine tailings, which are environmental pollutants in the Mongolian mine sector. For this purpose, this study selected 4 place of mine tailings of the Mongolian mines sector and carried out mineralogy evaluation of the valuable resources in the tailings. In this study, flotation was performed to separate and concentrate valuable resources in the tailings. Microwave nitric acid leaching was used to leach the valuable resources contained in the sample and to improve the Au grade. Chloride leaching attempted to leach Au from the leaching residues. XRD analysis of the tailings samples showed that most of the samples consisted of silicate minerals. As a result of confirming the content of the element through XRF analysis, the SiO₂ content was very high, the Fe₂O₃ content was 2.32-4.23%, and the content of PbO, CuO and ZnO components were all within 2%. As a result of flotation for the tailings samples, the recovery of Au was the highest in Bayanairag sample (95.38%). As a result of microwave nitric solution experiment on Au concentrate sample obtained by flotation, the content of Au in the microwave nitrate leaching residue increased by 12.15% from 192.72 g/ton to 216.14g/ton in Khamo sample, the highest increase was 57.58% in Bayanairag sample. TCLP tests on tailings generated after flotation showed dissolution characteristics within EPA. Chloride leaching test was performed to recover Au from solid residues. The leaching rate was 87.43-89.35% within 10 minutes. For Khamo sample, 100% Au was leached after 60 minutes of leaching time. Therefore, in order to process the tailings continuously generated in Mongolia, applying the same process as the present study is expected to effectively recover the valuable resources contained in the tailings.

• Journal of Soil and Groundwater Environment
• /
• v.7 no.3
• /
• pp.115-132
• /
• 2002

To distinguish the anthropogenic inputs from the chemical weathering with water-rock interaction on the chemical compositons of groundwater in Kwangju city, four different water groups were established based on the landuse type, lithology and topology. The sample from greenbelt area belongs to Group Ⅰ, whereas those from green buffer zone, urban area and industrial area belong to Group II, Group Ⅲ and Group Ⅳ, respectively. The geology of this city mainly consists of biotite granite and granitic gneiss. The concentration of main cations is subject to the behavior of feldspars, micas and carbonate minerals. Cl$\^$-/ and NO$_3$$\^$-/ are supplied by anthropogenic inputs such as domestic sewage whose concentration of these anions is highest in the Group Ⅲ samples. With the Piper diagram, the groundwaters of Group Ⅲ are mainly plotted in CaSO$_4$-CaCl$_2$ type, whereas those of other groups are plotted in Ca(HCO$_3$)$_2$ type, The calculation for the activities of ions and saturation indices of some minerals shows that most of the minerals are undersaturated and plotted in the area of equlibrium with kaolinite. Three factors were extracted from the factor analysis for chemical data. Factor 1 controlled by HCO$_3$$\^$-/, Ca$\^$2-/, SO$_4$$\^$2-/, Mg$\^$2+/ and Na$\^$+/, explains the dissolution of carbonate minerals. mica and plagioclase. Factor 2, controlled by Cl$\^$-/ and NO$_3$$\^$-/, explains the influence of artificial pollution. Factor 3, controlled by Mn, Fe and Zn is subject to the industrial waste water, but the evidence is not clear. Factor 1 is dominant in the Group I and II, indicating that those samples are subjected to natural chemical weathering, The higher scores of factor 2 in the Group Ⅲ samples indicate the potential artificial pollution.

• Journal of Soil and Groundwater Environment
• /
• v.14 no.6
• /
• pp.78-86
• /
• 2009

Applicability of CaO and steel slag as stabilizers in the treatment of field and paddy soils near Pungjeong mine contaminated with arsenic and cationic heavy metals was investigated from batch and column experiments. Immobilization of heavy metals was evaluated by TCLP dissolution test. Immobility of heavy metal ions was less than 15% when steel slag alone was used. This result suggests that $Fe_2O_3$ and $SiO_2$, known as the major component of steel slag, have little effect for the immobilization of heavy metal ions due to acidity of TCLP solution. Immobilization of cationic heavy metals was little affected by the ratio of CaO and steel slag while arsenic removal was increased as the ratio of steel slag to CaO increased. In the column test, concentrations of both arsenic and cationic heavy metals in effluents were below the water discharge guideline over the entire reaction period. This result can be explained by the immobilization of cationic heavy metals from the increased pH in soil solution as well as by the formation of insoluble $Ca_3(AsO_4)_2$. From this work, it is possible to suggest that arsenic and cationic heavy metals can be concurrently stabilized by application of both CaO and steel slag.

• Journal of the Mineralogical Society of Korea
• /
• v.16 no.4
• /
• pp.283-293
• /
• 2003

Domestic water treatment plants operate the rapid and slow filtering system using the filtering sands. Most of them are composed of beach sands, which have less sorption capacity of heavy metals as well as organic contaminants. Therefore, the development of fortified functional filtering materials with high removal capacity of organic and inorganic contaminants is needed to prevent the unexpected load of contaminated source water. This study aims to test the hydrochemical change and the removing capacity of heavy metals such as Cd, Cu, and Pb on the Jumunjin sand, feldspathic sand(weathering product of Jecheon granite), feldspathic mixing sand I(feldspathic sand mixed with 10 wt% zeolite), and feldspathic mixing sand II (feldspathic sand mixed with 20 wt% zeolite). Feldspathic mixing sand I and II showed the eruption of higher amounts of cations and anions compared with the Jumunjin sand and feldspathic sand. They also showed higher eruption of Si, Ca, $SO_4$ ions than that of Al, $NO_3$, Fe, K, Mg, and P. Feldspathic mixing sand II caused higher eruption of some cations of Na, Ca, Al than feldspathic mixing sud I, which is the result controlled by the dissolution of zeolite. Jumunjin sand and feldspathic sand showed very weak sorption of Cd, Cu and Pb. In contrast to this, feldspathic mixing sand I and II showed the high sorption and removal capacity of the increasing order of Cd, Cu and Pb. Feldspathic mixing sand II including 20% zeolite showed a fortified removal capacity of some heavy metals. Therefore, feldspathic mixing sand mixed with some contents of zeolite could be used as the fortified filtering materials for the water filtering and purification in the domestic water treatment plants.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.5
• /
• pp.680-687
• /
• 1999

To understand the role of shelf sediment in phosphorus biogeochemical cycle, we carried out sequential sediment extraction (SEDEX) of P and porewater analysis on 14 core samples collected in the South Sea of Korea, SEDEX classified P-pools into 5 phases and results are grouped into two categories: reactive P (loosely sorbed-P and Fe bound-P) and refractory P (detrital inorganic-p, authigenic mineral-P and organic-P). Total P concentrations are decreased with sediment depth in all samples as a result of dissolution to porewater. Reactive P comprises about $20\~50\%$ of total P, and iron bound-P is the major form consisting $70\~80\%$ of reactive P-pool. Iron bound-P decreases sharply with depth. Depth profiles of dissolved P concentration in porewater show mirror image of iron bound-P, revealing the role of FeOOH as a regulator of reactive P supply to overlying water column. Authigenic mineral-P consists less than $5\%$ of total P, thus removal of reactive P by converting into refractory P seems inefficient in shelf sediment. This implies that continental shelf sediment sequesters P temporarily rather than permanently. Results show local variation. Nakdong estuary receiving large amount of terrigenous input shows the highest concentration of total P and reactive P. Here iron oxyhydroxides at the surface sediment control the water column flux of P from sediment. Although total P content at the surface is comparable (500$\~$600 ${\mu}g{\cdot}g^{-1}$) between the South Sea and East China Sea, the former contains more iron bound-P and less derital inorganic-P than the latter. Reasons for the difference seem due in part to particle texture, and to biological productivity which depends roughly on the distance from land.

• Journal of Applied Biological Chemistry
• /
• v.64 no.4
• /
• pp.439-446
• /
• 2021

A field-scale study was conducted to evaluate the effect of organic matter amendments on the solubility of arsenic (As) in paddy soil and uptake by rice. Six organic matter (rice bran, rice straw, pig/cattle/fowls manure compost and swine liquid manure) were added to two polluted soils with high As (53 mg kg^-1) and low As concentration (28 mg kg^-1), and changes in soil solution constituents was monitored. The mean As concentrations in soil solution from the high As soil with rice bran, pig manure compost and swine liquid manure addition were significantly higher (0.61-1.15 mg L^-1) than that of the control (0.42-0.66 mg L^-1). Regression between As and Fe in soil solution indicated that As was attributable to reductive dissolution of Fe (hydr)oxides and it was driven by organic matter addition. Mean As concentrations in brown rice from the high As soil were 0.35-0.46 mg kg^-1, above the maximum safety level of inorganic As (0.35 mg kg^-1), and tended to be higher in organic matter amended soils than that of the control. The significant correlation between grain As and soil solution As was not observed and it was probably attributable to As tolerance of rice causing the reduction of As uptake and/or translocation to grain. However, considering the significant As release in soil solution from the high As soil and the tendency of grain As elevation after organic matter addition, it is needed to be cautious for food safety when amending organic matter to paddy soil with high As concentration.

• Economic and Environmental Geology
• /
• v.38 no.5 s.174
• /
• pp.547-561
• /
• 2005

General characteristics of groundwater contamination by As were reviewed with several recent researches, and its occurrence in groundwater of Korea was investigated based on a ffw previous studies and a groundwater quality survey in Nonsan and Geumsan areas. In Bangladesh, which has been known as the most serious arsenic calamity country, about $28\%$ of the shallow groundwaters exceeded the Bangladesh drinking water standard, $50{\mu}g/L$, and it was estimated that about 28 million people were exposed to concentrations greater than the standard. Groundwater was characterized by circum-neutral pH with a moderate to strong reducing conditions. Low concentrations of $SO_4^{2-}$ and $NO_3^-$, and high contents of dissolved organic carbon (DOC) and $NH_4^+$ were typical chemical characteristics. Total As concentrations were enriched in the Holocene alluvial aquifers with a dominance of As(III) species. It was generally agreed that reductive dissolution of Fe oxyhydroxides was the main mechanism for the release of As into groundwater coupling with the presence of organic matters and microbial activities as principal factors. A new model has also been suggested to explain how arsenic can naturally contaminate groundwaters far from the ultimate source with transport of As by active tectonic uplift and glaciatiion during Pleistocene, chemical weathering and deposition, and microbial reaction processes. In Korea, it has not been reported to be so serious As contamination, and from the national groundwater quality monitoring survey, only about $1\%$ of grounwaters have concentrations higher than $10{\mu}g/:L.$ However, it was revealed that $19.3\%$ of mineral waters, and $7\%$ of tube-well waters from Nonsan and Geumsan areas contained As concentrations above $10{\mu}g/:L.$. Also, percentages exceeding this value during detailed groundwater quality surveys were $36\%\;and\;22\%$ from Jeonnam and Ulsan areas, respectively, indicating As enrichment possibly by geological factors and local mineralization. Further systematic researches need to proceed in areas potential to As contamination such as mineralized, metasedimentary rock-based, alluvial, and acid sulfate soil areas. Prior to that, it is required to understand various geochemical and microbial processes, and groundwater flow characteristics affecting the behavior of As.