• KSBB Journal
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• v.29 no.3
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• pp.139-144
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• 2014

Microorganisms play a significant role in bioremediation of heavy metal contaminated seawater. In this study, we reported an effective removal of Cu and Zn in marine envionment by using Desulfovibrio desulfuricans (D. desulfuricans) which belong to sulfate reducing bacteria. D. desulfuricans showed stable growth characteristics in high salt concentration and had resistance to heavy metals. Cu and Zn was removed not only by physical adsorption on the surface of bacteria but also by precipitation reaction of microbial metabolism by D. desulfuricans in seawater. In case of different heavy metal concentration, Cu was effectively removed 85% at 25 ppm and 60% at 50 ppm and Zn was effectively removed 54% at 50 ppm and 46% at 200 ppm, respectively.

• Current Photovoltaic Research
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• v.3 no.4
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• pp.126-129
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• 2015

Over the last two decades, quantum dot (QD) solar cells have attracted much attention due to the unique properties of QDs, including band gap tunability, slow hot electron cooling, and multiple exiton generation effect. However, most of the QDs employed in photovoltaic devices contain toxic heavy-metals such as cadmium or lead, which may limit the commercial application. Therefore, recently, heavy-metal-free QDs such as Cu-In-S or Cu-In-Se have been developed for application in solar cells. Here, we review the research trends in heavy-metal-free QD solar cells, mainly focusing on Cu-In-Se QD-sensitized solar cells (QDSC).

• The Journal of Natural Sciences
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• v.19 no.1
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• pp.65-75
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• 2008

This research was conducted to determine heavy metal contents of soil and tree in pear orchard located near national road with heavy traffics. Topsoil (0-15 cm depth) and subsoil (15-30 cm) samples in pear orchard located within 40 m from national road had higher Pb, Cu, and Zn contents than background orchard (BG) and these heavy metal contents decreased with distance from road. Topsoil samples taken at 10 m from national road had 4 times higher level in Pb, 3 times in Cu, and 2.5 times in Zn compare to BG. The Cd contents of topsoil in orchard were higher than those of BG but were not in subsoil. Highest heavy metal contents of pear leaves in roadside orchard were 20.08 in Pb, 7.02 in Cu, 30.83 in Zn, and $1.68\;mm.kg^{-1}$ in Cd and these heavy metal contents in roadside orchard were higher than BG. Cd contents of fruit and Pb contents of fruit stalk in roadside orchard were higher than BG and these heavy metal contents decreased with distance up to 40 m from the road.

• Korean Journal of Environmental Biology
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• v.30 no.2
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• pp.136-142
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• 2012

Acute toxicity test of heavy metal (Cd, Cu, Zn) were examined using the hatching rates of fertilized eggs in the oliver flounder, Paralichthys olivaceus. Eggs were exposed to Cd, Cu, Zn (0, 10, 100, 500, 1000, 2500, 5000 ppb) and then normal hatching rates were investigated after 48 h. The normal hatching rates in the control condition (not including Cd, Cu and Zn) were greater than 80%, but suddenly decreased with increasing of heavy metal concentrations. Cd, Cu and Zn reduced the normal hatching rates in concentration-dependent way and a significant reduction occurred at concentration grater than 1000, 100, 100 ppb, respectively. The ranking of heavy metal toxicity was Zn>Cu>Cd, with $EC_{50}$ values of 584, 1015 and 1282 ppb, respectively. The no-observed-effect-concentration (NOEC) and the lowest-observed-effect-concentration (LOEC) showed each 100 and 500 ppb of normal hatching rates in exposed to Cu and Zn. The NOEC and LOEC of normal hatching rates in Cd were 500 ppb and 1000 ppb, respectively. From these results, the normal hatching rates of P. olivaceus have toxic effect at greater than the 100 ppb concentrations in Cu, Zn and the 500 ppb concentrations in Cd in natural ecosystems. These results suggest that biological assay using the normal hatching rates of P. olivaceus are very useful test method for the acute toxicity assessment of a toxic substance as heavy metal in marine ecosystems.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.787-798
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• 2005

The objectives of this study were to assess extraction kinetics of heavy metals with extraction times and to assess extraction efficiencies of heavy metals with concentrations and kinds of washing solutions. Target materials were obtained from disused metal mines. Washing solutions were water, HCl(0.1, 0.3, 1.0 N), EDTA(0.01, 0.05, 0.1 M), and sodium dodecyl sulfate(SDS, 0.1. 0.5, 1.0%). Extraction efficiencies of heavy metals by water and SDS were below 1%, and extraction efficiencies of Zn and Cd were higher than those of Pb and Cu. As results, water and SDS were not effective in extracting heavy metals from mine tailings as washing solution, but extraction efficiencies of Pb and Cu with SDS solution increased as extraction time increased. Extraction kinetics of heavy metals with HCl and EDTA were faster than those with water and SDS. The majority of heavy metals were extracted within 6 hours, and extraction kinetics was almost independent of the solution concentration. Extraction kinetics of heavy metals after 6 hours was slow, but extraction kinetics was dependent on the solution concentration. Also, as concentrations of HCl and EDTA solution were stronger, heavy metals were extracted rapidly and extraction efficiencies were increased. The extraction efficiency was high in order of Cd>Pb>Zn>Cu in using 1.0 N HCl, and Pb>Cd>Zn>Cu in using 0.1 M EDTA. Consequently, extraction effectiveness was highest for Pb in using HCl, and for Pb and Cd in using EDTA with concentration increase. Extraction time of over 6 hours was not effective in extracting heavy metals.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.1-7
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• 1999

This study was performed to investigate the contents of the heavy metals such as cadmium(Cd), copper(Cu), iron(Fe), lead(Pb) and zinc(Zn) in meat and meat products. For this experiment, each 20 samples of beef and pork were collected at slaughterhouse in Seoul areas and 45 samples of meat products(ham, sausage, processed meat and seasoned meat) were purchased from commercial food markets. The contents of the heavy metals was determined by atomic absorption spectrophotometry from Jan. to Nov. In 1998. The results obtained were summarized as follows ; 1. In Korean native beef, mean values of the heavy metals(mg/kg) were Pb : 0.14$\pm$0.10, Cd : 0.07$\pm$0.02, Cu : 1.73$\pm$0.95, Zn : 42.82$\pm$8.17 and Fe : 67.43$\pm$24.18, respectively. 2. In imported beef, mean values of the heavy metals(mg/kg) were Pb : 0.03$\pm$0.08, Cd : 0.06$\pm$0.02, Cu : 1.41$\pm$0.62, Zn : 42.93$\pm$4.95 and Fe : 40.06$\pm$12.77, respectively. 3. In pork, mean values of the heavy metals(mg/kg) were Pb : not detected, Cd : 0.09$\pm$0.02, Cu : 1.08$\pm$0.23, Zn : 19.49$\pm$6.02 and Fe : 30.21$\pm$10.51, respectively. 4. In ham, mean values of the heavy metals(mg/kg) were Pb : trace, Cd : trace, Cu . 1.19$\pm$0.46, Zn : 13.58$\pm$4.99 and Fe : 31.43$\pm$11.74, respectively. 5. In sausage, mean values of the heavy metals(mg/kg) were Pb : 0.15$\pm$0.34, Cd : 0.08$\pm$0.05, Cu : 1.15$\pm$0.46, Zn : 13.70$\pm$7.13 and Fe . 27.28$\pm$15.05, respectively. 6. In processed meat, mean values of the heavy metals(mg/kg) were Pb : 0.08$\pm$0.13, Cd : 0.09$\pm$0.04, Cu : 1.28$\pm$0.60, Zn : 14.72$\pm$7.09 and Fe : 24.04$\pm$10.33, respectively. 7 In seasoned meat, mean values of the heavy metals(mg/kg) were Pb : 1.05$\pm$2.21, Cd : 0.13$\pm$0.03, Cu : 1.06$\pm$0.16, Zn : 17.53$\pm$8.72 and Fe : 26.76$\pm$9.02, respectively.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.405-420
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• 2014

To investigate geochemical characteristics of soil and atmospheric environments by anthropogenic source, we have analyzed and determined heavy metal concentrations of the surface soils beneath roadside trees and leaves of Platanus occidentalis from 52 points in Seoul during autumn 2001. For comparison of the contents of heavy metal for the soil and leaf, we have analyzed heavy metal contents of the surface soils beneath roadside trees and leaves from 2 points in rural area of Yesan during the same time period. The composition of heavy metals of soils are relatively high for Cd, Co, Cr and Ni in industrial area (IA, Industrial Area) and high for Cu, Pb and Zn in heavy traffic area (HTA, Heavy Traffic Area). The heavy metal contents of rural area in Seoul are higher than those in Yesan. The differences of chemical compositions between the washed and unwashed leaves are high for Cd, Cu, Pb and Zn in the HTA. The element couples of Cd-Co, Cr-Ni and Pb-Zn for the soils had shown a good correlation and their contamination sources could be similar. The relationship for Pb-Cu and Cu-Zn showed good correlation in Platanus leaves. The relationship between soils and unwashed leaves show a good correlation for Cr, Cu, Pb and Zn but low correlation for Cd, Co, Fe, Mn and Ni. It is thought that the Cr, Cu, Pb and Zn were derived from contaminants of soils, whereas Cd, Co, Fe, Mn and Ni were originated from atmospheric source. From the spatial variations of elements for soils and leaves, Ni and Cr were dominant in the soils of IA and Cd, Cu and Zn were dominant in those of HTA. The Contamination by Cd-Pb and Cu-Zn in unwashed leaves were analyzed to show similar patterns. Using the enrichment factors (EF) of heavy metals in unwashed leaves, the EF sequences were to be Cu, Zn, Pb, Mn, Co, Ni, Cd and Cr. We identified that Cu, Zn, Pb and Mn were most problematic of environmental hazard in Seoul.

• Corrosion Science and Technology
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• v.17 no.4
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• pp.176-182
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• 2018

Corrosion of the Cu alloy with 10wt% Ni in stagnant seawater with residual free chlorine was investigated. Despite that fact that Cu alloys are widely used for seawater applications due to their stubborn resistance to chloride attack, not much is known as to how the residual free chlorine in seawater affects corrosion of Cu and its alloys. In this work, immersion tests were conducted in the presence of different levels of chlorine for 90-10 Cu-Ni samples, one of the most frequently used Cu alloys for seawater application, mostly in shipbuilding. The results revealed no evidence for accelerated corrosion of the Cu-Ni alloy even in the presence of 5 ppm residual chlorine in seawater, signifying that the Cu-Ni alloy can be more tolerant to residual chlorine that has been commonly cited by the shipbuilding industry. However, comparison of polarization behavior of the alloy samples in the presence of different electrolytes with different concentrations of residual chlorine suggests that higher concentration of chlorine could increase the corrosion rate of the Cu-Ni alloy. Furthermore, it is suggested that microorganisms in the seawater could increase the corrosion rate of the Cu-Ni alloy by encouraging exfoliation of the corrosion product off the metal surface.

• Journal of Environmental Science International
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• v.14 no.7
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• pp.691-697
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• 2005

Waste sludge may be used to recovery wastewater contaminated with heavy metals. The waste sludge is an inexpensive readily available source of biomass for biosorption with metal-bearing wastewater. The biosorption of heavy metals such as Pb(II), Cu(II), Cr(II), and Cd(II) onto waste sludge was investigated in batch ex­periments and waste sludge loaded heavy metals was separated by dissolved air flotation. The biosorption equi­bria of heavy metals could be described by Langmuir and Freundich isotherms. The adsorption capacity for waste sludge was in the sequence of Pb(II)>Cr(II)>Cu(II)>Cd(II). The system attained equilibrium about 20 min. The Langmuir and Freundlich adsorption model effectively described the biosorption equilibrium of Cu(II) and Cr(II) ions on waste sludge. Maximum adsorption capacity of Cu(II) and Cr(II) were 196.08 and 158.73 mg/g, respectively. Solid-liquid separation efficiencies were kept above $95\%$ on waste sludge loaded heavy metals, and were decreased with pH increasing.

• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.92-97
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• 2003

The purpose of this study is heavy metal absorption of recycled PET(poly ethylene terephatalate) NWF(non woven faric). The results of test are summarized as follows; Heavy metal abworption rates in Ni ions were higher then Zn and Cu ions, whereas heavy metal absorption rates by sulfonation times were not different. The heavy metal absorption times have a higher tendency from 60 min to 120 min. There were significant negative correlations among the amount used CSA(Chloro Sulfuric Acid) and the amount of absorption Zn(r = -0.33784, p < 0.05), Cu(r = -0.61177, p < 0.01) ions, whereas correlations between heavy metal absorption rates and sulfonation times were not significant. There were significant positive correlations among the amount of absorption Zn ions and the amount of absorption Ni(r = 96475, p < 0.014), Cu(r = 0.51614, p < 0.01) ions, likewise the positive correlations between the amount of absorption N ions and the amount of absorption Cu(r = 0.54766) ions were significant(p < 0.01).