• Economic and Environmental Geology
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• v.39 no.3 s.178
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• pp.329-342
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• 2006

The purpose of this study is to determine the geochemical characteristics for the stream sediments in the Konyang area. So we can estimate the environment contamination and understand geochemical disaster. We collect the stream sediments samples by wet sieving along the primary channels and slowly dry the collected samples in the laboratory and grind to pass a 200mesh using an alumina mortar and pestle for chemical analysis. Mineralogy, major, trace and rare earth elements are determined by XRD, XRE, ICP-AES and NAA analysis methods. For geochemical characteristics on the geological groups of stream sediments, the studied area was grouped into quartz porphyry area, sedimentary rock area, anorthosite area and gneiss area. Contents of major elements for the stream sediments in the Konyang area were $SiO_2\;41.86{\sim}76.74\;wt.%,\;Al_{2}O_{3}\;9.92{\sim}30.00\;wt.%,\;Fe_{2}O_{3}\;2.74{\sim}12.68\;wt.%,\;CaO\;0.22{\sim}3.31\;wt.%,\;MgO\;0.34{\sim}3.97\;wt.%,\;K_{2}O\;0.75{\sim}0.93\;wt.%,\;Na_{2}O\;0.25{\sim}1.92\;wt.%,\;TiO_{2}\;0.40{\sim}3.00\;wt.%,\;MnO\;0.03{\sim}0.21\;wt.%,\;P_{2}O_{5}\;0.05{\sim}0.38\;wt.%$. The contents of trace and rare earth elements for the stream sediments were $Cu\;7{\sim}102\;ppm,\;Pb\;15{\sim}47\;ppm,\;Sr\;48{\sim}513\;ppm,\;V\;29{\sim}129\;ppm,\;Zr\;31{\sim}217\;ppm,\;Li\;14{\sim}94\;ppm,\;Co\;5.6{\sim}32.1\;ppm,\;Cr\;23{\sim}259\;ppm,\;Cs\;1.7{\sim}8.7\;ppm,\;Hf\;2.1{\sim}109.0\;ppm,\;Rb\;34{\sim}247\;ppm,\;Sc\;4.5{\sim}21.9\;ppm,\;Zn\;24{\sim}609\;ppm,\;Sb\;0.8{\sim}2.6\;ppm,\;Th\;3{\sim}213\;ppm,\;Ce\;22{\sim}1000\;ppm,\;Eu\;0.7{\sim}5.3\;ppm,\;Yb\;0.6{\sim}6.4\;ppm$. Generally, the contents of $Al_{2}O_{3}\;and\;SiO_2$ had a good relationships with each other in rocks but it had a bad relationships in stream sediments for this study area. The contents of $Fe_{2}O_3$, CaO, MnO and $P_{2}O_{5}$ had a good relationships with major and minor elements in stream sediments of this study area. The contents of Co and V in the stream sediments had a good relationships with other toxic elements.

• The Journal of the Petrological Society of Korea
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• v.19 no.3
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• pp.209-225
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• 2010

The Shinri area near the Yedang Lake, the eastern part of the Hongseong area in SW Gyeonggi Massif, consists of the Neoproterozoic Duckjeongri granodiorite-tonalite, mylonitized amphibole-bearing orthogneiss and impure marble with lens-shaped garnet-bearing metabasites. In this paper, we report mineralogical and geochemical data of Neoproterozoic lens-shaped garnet-bearing metabasites within marble of the Shinri area. The $SiO_2$ contents of garnet-bearing metabasites in marble vary between ~46.98 and 51.17 wt%, and the $Na_2O$ + $K_2O$ contents fall between ~1.95 and 2.85 wt%, similar to the tholeiitic sub-alkaline basaltic rocks. In the Zr/Y vs. Zr diagram, garnet-bearing metabasites also plot in the subalkaline basaltic rocks. The chondrite-normalized REE patterns for Shinri garnet-bearing metabasites show relatively flat patterns to that of chondrite. They show slight LREE-enriched and depleted patterns. The major and trace element data from lens-shaped garnet-bearing metabasites in marble of the Shinri area suggest that these rocks were formed in within plate. In contrast, previous major and trace element data of high pressure type garnet-bearing metabasites from the mafic-ultramafic complex in the Baekdong and Bibong areas suggest that these rocks were formed in a nascent arc to backarc spreading center within subduction zone setting. Based on mineral assemblage and mineral chemistry, P-T estimates for Shinri garnet-bearing metabasites are 9.6-12.7 kb, $695-840^{\circ}C$ for inclusions in the core, and 9.6-13.6 kb, $630-755^{\circ}C$ for those in the rim. These P-T estimates are distinct from those of the Baekdong and Bibong garnet-bearing metabasites with isothermal decompressional retrograde P-T path. In addition to Triassic tectonic activity previously reported in the Shinri area of Hongseong, the details of metamorphic history such as protolith age and Neo-Proterozoic metamorphic episode need to be solved.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.328-336
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• 2008

Metal mining district drainage is a well recognized source of environmental contamination. Oxidation of metal sulfides produces acidic and metal-rich waters that contaminate local surface water and ground water in mines, mine dumps, and tailing impoundments. This monitoring study was carried out to investigate the stream water quality and pollution as affected by the Sambo mine drainage in relation to the relative distance from the mine. It obvious that pH values of the mine drainage ranged from 5.8 to 6.9, while the average concentrations of the dissolved chemical constituents for EC, $SO_4^{2-}$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were $1.77\;dS\;m^{-1}$, 929, 14.6, 263.3, and 46.9 mg/L in mine drainage discharged from the main waste rock dumps (WRD), respectively. Furthermore, EC values and sulfate concentrations exceeded the critical toxicity levels in agricultural water for rice plant ($1.0\;dS\;m^{-1}$ for EC and 54.0 mg/L for $SO_4^{2-}$). Also, the average of dissolved cadmium concentrations ($0.016{\sim}0.021\;mg/L$) was higher than water quality standard (0.01 mg/L) for agricultural water in Korea, in addition to Zn, Fe and Mn were higher than trace metals maximum concentrations which recommended by FAO for irrigation water. The results indicate that mine drainage discharged from the Sambo mine affected stream water at least to distance of 1 km downstream of the mine water discharge point. EC values, $SO_4^{2-}$ and $Ca^{2+}$ concentrations in discharged water positively correlated with dissolved Cd, Zn, Al and Mn concentrations, while the pH values negatively correlated. In addition, EC values, $SO_4^{2-}$ and $Ca^{2+}$ concentrations were negatively correlated with pH values.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.3
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• pp.152-158
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• 2009

Various fabrication methods have been used to synthesize sapphire which has qualities of jewelry well beyond the industrial class. Among them, the flux sapphire of Chatham Company which has as high value as jewelry was selected in order to compare natural and synthetic sapphire. First, the WD-XRF (Wavelength dispersive x-ray fluorescence spectrometer) was used to analyze the chemical composition of natural and synthetic sapphire. Although natural sapphire had very diverse chemical compositions, flux sapphire had small quantities of Mo, Pt and Pb elements in addition to the similar chemical ingredients to natural one. Pt is decisive proof of flux sapphire. Next, by investigating spectroscopic characteristics using UV-VIS Spectrophotometer after heat treatment at high temperatures of $1300^{\circ}C$ and $1500^{\circ}C$, the variation of 690 nm absorbance related to $Cr^{3+}$ was detected in the natural sapphire while those of the 690 nm absorbance (related to $Cr^{3+}$) as well as absorbance of 376 nm and 388 nm ($Fe^{3+}$) were seen in the flux sapphire. It was found that the difference in the absorbance variation of flux sapphire is greater than that of natural sapphire after heat treatment. The chemical composition and spectrum analysis were utilized to compare the natural sapphire and the flux synthetic sapphire.

• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.577-588
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• 2001

Eu doped YRO$_4$ (R=As, Nb, P, V) red phosphors were prepared by the combinatorial chemistry method. The quaternary material library of tetrahedron-type composition array was designed to investigate the luminescence of the host material under UV and VUV excitations (254, 147 nm). The photoluminescent characteristics of the samples were comparable to the commercially available red phosphors such as (Y, Gd)BO$_3$: $Eu^{3+}$ and Y$_2$O$_3$: In view of the luminescence yield, V rich region was found to be optimum under UV excitation. But the results under VUV excitation were different from those of UV excitation, the samples of the composition containing a large amount of P shows the highest luminescence. Especially, higher luminescence was obtained in $Y_{0.9}$(A$S_{0.06}$N$B_{0.06}P_{0.83}V_{0.06}$) O$_4$: $Eu_{0.1}$ phosphors than commercial (Y, Gd)BO$_3$red phosphors under 147 nm excitation.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.146-151
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• 1997

To get the basic information for the establishment of the optimum levels of upland soil fertility and fertilizer application, two hundred soil samples were collected from the major vegetable cultivation areas such as Chinese cabbage, reddish, garlic, onion, red pepper, watermelon and potato fields. The soil samples were analyzed for the soil chemical properties and micro elements. Soil pH, organic matter and magnesium contents were lower than the standard level for upland soil improvement, while the phosphate and potassium contents were higher than the standard levels. The organic matter and nitrogen contents were increased in the potato field soils, the available phosphate contents were increased in the red pepper field soils and the exchangeable potassium contents were increased in reddish and red pepper field soils, to compared with the past deta. The contents of micro elements were ranged in 14~282 for Fe, 13~98 for Mn, 0.5~2.8 for Cu and 0.6~5.0 mg/kg for Zn respectively, and they were in order of Fe>Mn>Zn>Cu.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.83-88
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• 2017

We introduced disposable amperometric immunosensors for the detection of Sildenafil and Vardenafil (SDF/VDF) based on screen printed carbon electrodes. The developed immunosensors were used as a non-competitive sandwich-type enzyme immunoassay with a horseradish peroxidase label. The sensors were constructed on screen printed carbon electrodes by the simple electrochemical deposition of a reduced graphene oxide and chitosan (ErGO-CS) composite. To evaluate the sensing chemistry and optimize the sensor characteristics, a series of electrochemical experiments were carried out including electrochemical impedance spectroscopy, cyclic voltammetry and amperometry. The sensors showed a linear response to SDF/VDF concentrations in a range from 100 pg/mL to 300 ng/mL. The lower detection limit was calculated to be 55 pg/mL, the sensitivity was calculated to be $1.02{\mu}Ang/mL/cm^2$, and the sensor performance exhibited good reproducibility with a relative standard deviation (RSD) of 7.1%. The proposed sensing chemistry strategy and the sensor format can be used as a simple, cost-effective, and feasible method for the in-field analysis of SDF/VDF in functional or health supplement food samples.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.714-722
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• 2019

Catalysts were prepared by using incipient wetness impregnation method with 17 wt% Ni on a support ($SiO_2-Y_2O_3$, $Al_2O_3$, $SiO_2-ZrO_2$, $SiO_2$, $TiO_2$, MgO) and the catalytic activity in the reductive amination of ethanol with ammonia in the presence of hydrogen was compared and evaluated. The catalysts used before and after the reaction were characterized using X-ray diffraction, nitrogen adsorption, ethanol-temperature programmed desorption (EtOH-TPD), isopropanol-temperature programmed desorption (IPA-TPD), and hydrogen chemisorption etc. In the case of preparing $ZrO_2$ and $Y_2O_3$ supports, the small amount of Si dissolution from the Pyrex reactor surface provoked the formation of mixed oxides $SiO_2-ZrO_2$ and $SiO_2-Y_2O_3$. Among the catalysts used, $Ni/SiO_2-Y_2O_3$ catalyst showed the best activity, and this good activity was closely related to the highest nickel dispersion, and low desorption temperature in EtOH-TPD and IPA-TPD. The low catalytic activity on Ni/MgO catalysts showed low activity due to the formation of NiO-MgO solid-solutions. In the case of $Ni/TiO_2$, the reactivity was low due to the low nickel metal phase due to strong metal-support interaction. In the case of using a support as $SiO_2-Y_2O_3$, $Al_2O_3$, $SiO_2-ZrO_2$, and $SiO_2$, the selectivities of ethylamines and acetonitrile were not significantly different at similar ethanol conversion.

• Clean Technology
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• v.27 no.2
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• pp.139-145
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• 2021

The purpose of this study is to recover valuable metals from spent batteries using a dry process. We focused on the effect of the smelting temperature on the composition of recovered solid and liquid products and collected gaseous products. After removal of the cover, the spent battery was left in NaCl solution and discharged. Then, the spent battery was made into a powder form through a crushing process. The smelting of the spent battery was performed in a tubular electric furnace in an oxygen atmosphere. For spent lithium-ion batteries, the recovery yield of the solid product was 80.1 wt% at a reaction temperature of 850 ℃, and the final product had 27.2 wt% of cobalt as well as other metals such as lithium, copper, and aluminum. Spent nickel-hydrogen batteries had a recovery yield of 99.2 wt% at a reaction temperature of 850 ℃ with about 37.6 wt% of nickel and other metals including iron. For spent nickel-cadmium batteries, the yield decreased to 65.4 wt% because of evaporation with increasing temperature. At 1050 ℃, the recovered metals were nickel (41 wt%) and cadmium (12.9 wt%). Benzene and toluene, which were not detected with the other secondary waste batteries, were detected in the gaseous product. The results of this study can be used as basic data for future research on the dry recycling process of spent secondary batteries.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.76-81
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• 1998

Physical adsorption on a silica gel(pore size of 80 nm, particle size of $10{\mu}m$)has been studied for binary mixture of acetone diluted in $CO_2$ by use of a FTIR transmission technique and we have compared the result of FTIR transmission technique with that of a chromatographic technique. Measurements were made at 313.2 K and under pressures up to 15MPa. As the pressure increases from 0.1MPa, the IA(Integral Absorbance) of the hydrogen-bonded OH groups interacting with acetone and adsorbed amount by use of a chromatographic technique increases at first, and reaches a maximum at a pressure below the critical pressure of $CO_2$, and then the intensities decrease gradually with increasing pressure. It is found that the pressure dependency of the chromatographic isotherm is a little larger than that of spectroscopic isotherm in the supercritical fluid region. This difference might be attributable to the weaker van der Waals force and relatively stronger hydrogen-bonding force influencing the adsorption of acetone on the sllica gel. The unique spectroscopic characteristics of amine group which vibrational frequencies of hydroxyl groups on the silica gel surface shift downward to about $1300cm^{-1}$ were measured from experimental result of triethylamine diluted in $CO_2$ or $N_2$.