• Korean Journal of Environmental Agriculture
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• v.3 no.1
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• pp.36-44
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• 1984

Waters, sediments and crucian carps samples collected bimonthly from Nakdong river during- the period of August 1982 to June 1983 were analyzed for organophosphorus pesticide residues by GLC equipped with a flame photometric detector. Among the environmental samples, IBP, diazinon, phenthoate, parathion, malathion and fenitrothion residues were found only in waters and crucian carps and sediments samples were devoid of the residues. In addition, seasonal variations of the residues in waters and crucian carps were observed. Waters and crucian carps samples collected in August, when pesticides are generally in great demand, contained all the organophosphorus pesticide residues while no organophosphorus were detected in waters and crucian carps samples collected in February, April or December. The most abundant residues in the two environmental samples were diazinon and IBP and residue levels of parathion, malathion and fenitrothion were found extremely low.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.34-39
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• 2006

Pure and Fe-doped CuO thin-film and powder samples were prepared using a sol-gel method. Undoped CuO films exhibited monoclinic structure and p-type electrical conductivity $(\~10^{-2}\;{\Omega^{-1}\;cm^{-1}$ due to copper deficiency. On the other hand, CuO: Fe films were found to be insulating and Li doping on the films led to a restoration of p-type conductivity and a ferromagnetic hysteresis behaviour at room temperature. The observed properties far the CuO : Fe, Li films can be explained in terms of hole creation by substitution of $Li^+$ for $Cu^{2+}$ sites and mediation of long-range interactions between $Fe^{3+}$ ions by the $Li^+$-induced defect states. CuO: Fe powders exhibited a ferromagnetism at room temperature with its strength being dependent on post-annealing temperature. Mossbauer measurements on the CuO: Fe films and powders revealed that the octahedral $Cu^{2+}$ sites are mostly substituted by $Fe^{3+}$ ions.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.305-313
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• 2010

Mineralogical characteristics of Cu-Co ores from the Central African Copperbelt in the Democratic Repblic of Congo are studied using powder X-ray diffractometer, general area detector X-ray diffractometer, and electron proble microanalyzer. Black ores are mainly composed of heterogenite (cobalt oxide/hydroxide mineral) and malachite (copper carbonate mineral), whereas green ores are only composed of malachite. Heterogenite shows very bright white color under the reflected microscope, and belongs to 3R polytype, because it has d-spacings at $4.39{\AA}$ and $2.316{\AA}$. Since NiO and $Fe_20_3$ content of heterogenite are lower than those of 3R polytype from other localities, it cannot completely exclude the presence of 2H polytype in heterogenite from this study. Malachite is light grey color under the reflected microscope with approximate chemical formula of $Cu_{1.97}Co_{0.02}Fe^{2+}{_{0.01}}CO_3(OH)_2$. Heterogenite and malachite were probably formed at the supergene emichment stage, the last mineralization stage in the Central African Copperbelt. Cobalt seems to be much more emiched in the black supergene (oxy)hydroxide ore than those in the primary sulfide ore.

• 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.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.743-753
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• 2020

This study analyzed heavy metal concentration, mineral composition, and spectral characteristics of heavy metal contaminated soil samples of cropland and rice field located in downstream of abandoned Okdong coal mine. X-ray fluorescence analysis detected heavy metal elements including cadmium, copper, arsenic, lead, zinc and nickel in the soils. Both cropland and rice field samples were severely contaminated with arsenic showing higher concentration over the concerned standard. The pollution index of cropland samples was higher than that of rice field samples. X-ray powder diffraction analysis identified that the mineral composition of cropland and rice field samples is similar with quartz, calcite, kaolinite, illite, smectite, magnetite and hematite. The range of organic matter content were more widely distributed in cropland samples. The spectral analysis showed that the reflectance spectra and the absorption features of cropland and rice field samples were alike. The absorption features that appeared near 490nm and 900nm were attributed to the ferric iron, and clay minerals such as kaolinite and smectite caused the absorption features at 1410nm, 1910nm and 2200nm. The reflectance of the soil spectral decreased with an increase in organic content. The absorption depths of both types of soil samples decreased with higher organic matter content at 490nm and 1916nm as well as higher heavy metal concentration.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.203-214
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• 2014

We measured the contact dermatitis-causing substances concentrations in 28 commercial oxidative hair-coloring products. This study was aimed to provide the fundamental data about oxidative hair-coloring products. We selected 10 oxidation dyes (p-phenylenediamine, toluene-2,5-diamine, m-phenylenediamine, nitro-p-phenylenediamine, p-aminophenol, m-aminophenol, o-aminophenol, p-methylaminophenol, N,N'-bis(2-hydroxyethyl)-p-phenylenediamine sulfate, 2-methyl-5-hydroxyethylaminophenol) and 4 heavy metal (nikel; Ni, chromium; Cr, cobalt; Co, copper; Cu) as contact dermatitis-causing substances. To identify 10 oxidation dyes, hexane-2% sodium sulfite was used for the rapid and simple extraction and ultra performance liquid chromatography (UPLC) analysis was used for simultaneous analysis in 12 minutes. 10 oxidative dyes were detected as indicated on the product packaging and each concentration was lower than prescribed upper concentration limit by pharmaceutical manufacturing standards. And we analysed inductively coupled plasma-optical emission spectrophotometer (ICP-OES) for content search of heavy metal after microwave digestion. The heavy metal average concentration in oxidative hair-coloring products was 0.572 ${\mu}g/g$ for Ni, 3.161 ${\mu}g/g$ for Cr, 2.029 ${\mu}g/g$ for Co, 0.420 ${\mu}g/g$ for Cu, respectively. The average of concentration in powder type (henna) was higher than those of other foam and cream type oxidative hair-coloring products as follows; 1.800 ${\mu}g/g$ for Ni, 10.127 ${\mu}g/g$ for Cr, 7.082 ${\mu}g/g$ for Co, 1.451 ${\mu}g/g$ for Cu. Hair coloring products were classified into the six colors - black, dark brown, brown, dark brown, light brown, red brown and analyzed. Brown color had the highest average concentration of Co and the others had the highest average concentration of Cr.