• Journal of Environmental Science International
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• v.20 no.6
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• pp.687-700
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• 2011

A new $N_3-O_2$ pentadentate ligand, H-BHPT, was synthesized. Hydrochloric acid salts of Br-BHPT, Cl-BHPT, $CH_3O$-BHPT and $CH_3$-BHPT, having Br-, Cl-, $CH_{3-}$ and $CH_3O-$ substituents at the para position of the phenol hydroxyl group of H-BHPT were synthesized. Hydrochloric acid salts of 3OH-BHPT and 4OH-BHPT, having different position of the phenol hydroxyl group of H-BHPT were also synthesized. The synthesis of each ligand was confirmed by C. H. N. atomic analysis and $^1H$ NMR, $^{13}C$ NMR, UV-visible, and mass spectra. The calculated proton dissociation constants ($log{K_n}^H$) of the phenol hydroxyl group and secondary amine group of the synthesized $N_3-O_2$ ligands showed five steps of the proton dissociations. The order of the overall proton dissociation constants ($log{\beta}_p$) of the ligands was Br-BHPT < Cl-BHPT < H-BHPT < $CH_3O$-BHPT < $CH_3$-BHPT. The order agreed with that of Hammett substituent constants (${\delta}_p$). However, dissociation steps of 3OH-BHPT were four and that of 4OH-BHPT was three. The calculated stability constants ($logK_{ML}$) between the ligands and transition metal ions agreed with the order of $log{\beta}_p$ values of the ligands. The order of the stability constants between the transition metal ions with the synthesized ligands was Co(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II). The order agreed well with that of the Iriving-Williams.

• Analytical Science and Technology
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• v.32 no.6
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• pp.233-242
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• 2019

Substance identification is the first step of the REACH registration. It is essential in terms of Classification, Labelling and Packaging (CLP) regulation and because even trace amounts of impurities or additives can affect the classification. In this study, a scheme for the screening, quantification, and interpretation of trace amounts of hazardous inorganic substances is proposed to detect the presence of more than 0.1% hazardous inorganic substances that have been affecting the hazard classification. An exemplary list of hazardous inorganic substances was created from the substances of very high concern (SVHCs) in REACH. Among 201 SVHCs, there were 67 inorganic SVHCs containing at least one or ~2-3 heavy metals, such as As, Cd, Co, Cr, Pb, Sb, and Sn, in their molecular formula. The inorganic SVHCs are listed in excel format with a search function for these heavy metals so that the hazardous inorganic substances, including each heavy metal and the calculated ratio of its atomic weight to molecular weight of the hazardous inorganic substance containing it, can be searched. The case study was conducted to confirm the validity of the established scheme with zinc oxide (ZnO). In a substance that is made of ZnO, Pb was screened by XRF analysis and measured to be 0.04% (w/w) by ICP-OES analysis. After referring to the list, the presence of Pb was interpreted just as an impurity, but not as an impurity relevant for the classification. Future studies are needed to expand on this exemplary list of hazardous inorganic substances using proper regulatory data sources.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.339-342
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• 2007

$Cu(In_{1-x}Ga_{x})Se_2$(CIGS)는 매우 큰 광흡수계수를 가지고 있으므로 박막형 태양전지의 광흡수층 재료로서 많은 연구가 진행되고 있다. 박막이 태양전지의 광흡수층으로 이용되기 위해서는 큰 결정크기와 평탄한 표면, 적당한 전기적 특성을 가져야 한다. 이러한 특성들은 CIGS 박막의 조성에 큰 영향을 받고 있는 것으로 보고되고 있다. 본 연구에서는 동시증발법을 이용하여 Cu/(In+Ga) 비를 0.9로 고정한 후 Ga 조성(Ga/(In+Ga)의 비 : 0.32, 0.49, 0.69, 0.8, 1)을 변화시켜 Wide band gap CIGS 박막태양전지를 만들었다. 기판은 soda line glass를 사용하였고 뒷면 전극으로는 Mo를 스퍼터링법으로 증착하였다. 또한 버퍼층으로는 기존에 쓰이고 있는 CdS를 CBD(Chemical Bath Deposition)법으로 층착시켰으며, 윈도우층으로는 i-ZnO/n-ZnO를 스파터링 법으로 층착하였다. 그리고 앞면전극으로는 Al을 E-beam 으로 증착하였다. 분석은 XRD, SEM, QE로 분석하였다. 위 실험에서 얻은 결과로는 Ga/(In+Ga)비가 증가할수록 Cu(In,Ga)Se2 박막은 회절 peak들이 큰 회절각으로 이동하였고, 이것은 Ga 원자와 In 원자의 원자반경의 차이에서 기인된 것으로 사료된다. 또한 Ga 조성이 증가할수록 단파장 쪽으로 이동하는 것을 볼 수 있으며, Voc가 증가하다가 에너지 밴드캡이 1.62 eV 이상에서는 Voc가 감소하는 것을 볼 수 있는데 이것은 Ga 조성이 증가할수록 에너지 밴드캡이 커지면서 defect level 이 존재하기 때문인 것으로 사료된다. Ga/(In+Ga)비가 1일 때의 변환효율은 8.5 %이고， Voc : 0.74 (V), Jsc : 17.2 ($mA/cm^{2}$), F.F : 66.6(%) 이다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.399-399
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• 2009

CIS계 화합물 태양전지는 높은 광흡수계수와 열적 안정성 및 Ga 조성 조절을 통한 밴드갭 조절이 용이해 고효율 박막 태양전지로 각광 받고 있다. CIS 태양전지의 광 흡수층 제조 방법으로는 여러 가지 방법이 있지만 본 연구에서는 가장 높은 에너지 변환 효율을 달성한 Co-Evaporation 방법을 사용하기로 하였다. 미국의 NREL의 경우 Co-Evaporation 방법을 사용해 20%의 에너지 변환 효율을 달성한 바가 있다. 하지만 이러한 효율의 태양전지는 실험실에서 연구용으로 제작한 아주 작은 면적으로 태양전지 양산화에 그대로 적용하기는 힘들다. 따라서 CIGS 태양전지의 양산화 적용을 위해 대면적화가 필수적이다. 본 연구에서는 기존의 3 stage 방식을 이용해 광흡수층을 증착하여 최적화 조건을 연구하였다. 또한 기판의 면적 증가에 따라 효율과 Voc, Jsc, F.F가 얼마나 감소하는지 실험하여 보았다. 기판은 soda lime glass를 사용 하였으며 후면 전극으로 약$1{\mu}m$ 두께의 Mo를 DC Supptering 방법을 이용해 증착하였다. 다음으로 약 $2{\mu}m$이상의 광흡수층을 Co-Evaporation 방법을 이용하여 증착 하였으며 buffer층으로는 약 50nm의 CdS층을 CBD방법을 이용하여 제조 하였다. TCO층으로 약 50nm의 i-ZnO와 약 450nm의 Al-ZnO를 RF Sputtering 방법을 이용하여 증착 하였다. 마지막으로 앞면 전극으로 약 $3{\mu}m$의 Al을 Thermal Evaporation 방법으로 증착하였다. 태양전지 소자의 면적은 $0.49cm^2$, $25cm^2$, $100cm^2$로 각각 면적을 달리하며 효율을 비교 분석하였다.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1085-1088
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• 2011

Heavy metal concentration as well as chemical composition were surveyed in commercial liquid pig manure to provide the basic information for mitigation research of hazardous material to agro-product. Seventy-five samples of liquid pig manure were collected and analyzed from 2009 to 2010 nationwide. Average contents of T-N, $P_2O_5$, and $K_2O$ were 0.29%, 0.08%, and 0.11%, respectively. The contents of heavy metals ranged from 0.001~0.083 for As, 0.001~0.108 for Cd, 0.002~0.495 for Cr, 0.07~47.8 for Cu, ND~0.005 for Hg, 0.035~1.033 for Ni, ND~0.291 for Pb, and $0.75{\sim}342.4mg\;L^{-1}$ for Zn, respectively. It was noted that among 75 samples, only four samples exceeded the Zn guideline ($130mg\;L^{-1}$) of liquid fertilizer derived from livestock manure but others were not exceeded the regulation.

• Journal of Environmental Science International
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• v.18 no.7
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• pp.735-746
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• 2009

Hydrochloric acid salt of a new $N_2O_3$ pentadentate ligand, N,N'-Bis(2-Hydroxybenzyl)-1,3-diamino-2-propanol(H-BHDP 2HCl) was synthesized. Br-BHDP 2HCl, CI-BHDP 2HCl, $CH_3-BHDP$ 2HCl and $CH_3O$-BHDP 2HCl having Br, Cl, $CH_3$ and $CH_3O$ substituents at 5-position of the phenol group of H-BHDP 2HCl were also synthesized. The potentiometry study in aqueous solution revealed that the proton dissociations of the synthesized ligands occurred in four steps and their order of the calculated overall proton dissociation constants($log{\beta}_p$) was Br-BHDP < Cl-BHDP < H-BHDP < $CH_3O-BHDP$ < $CH_3-BHDP$. The order showed a similar trend to that of Hammett substituent constants(${\delta}_p$). The order of the stability constants($logK_{ML}$) was Co(II) < Ni(II) < Cu(II) < Zn(II) < Cd(II) < Pb(II). The order in their stability constants ($logK_{ML}$) of each transition metal complex agreed with that of the overall proton dissociation constants ($log{\beta}_p$).

• Analytical Science and Technology
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• v.10 no.4
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• pp.282-290
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• 1997

The sorption and desorption properties of U(VI), Th(IV), Zr(IV), Cu(II), Pb(II), Ni(II), Zn(II), Cd(II) and Mn(II) ions on XAD-16-[4-(2-thiazolylazo)orcinol] (TAO) chelating resin were studied by elution method. The effect was examined with respect to overall capacity of each metal ion, separation of mixed metal ions, flow rate and concentration of buffer solution for optimum condition of sorption. The overall capacities of some metal ions on this chelating resin were 0.35nmol U(VI)/g resin, 0.49nmol Th(IV)/g resin, 0.41nmol Cu(II)/g resin, and 0.31nmol Zr(IV)/g resin, respectively. The elution order of metal ions obtained from breakthrough capacity and overall capacity at pH 5.0 was Th(IV)>Cu(II)>U(VI)>Zr(IV)>Pb(II)>Ni(II)>Zn(II)>Mn(II)>Cd(II). The group separation of mixed metal ions was possible by increasing pH in pH range 2~5 at a flow rate of 0.28mL/min. Characteristics of desorption were investigated with desorption agents such as $HNO_3$, HCl, $HClO_4$, $H_2SO_4$, and $Na_2CO_3$. It was found that 2M $HNO_3$ showed high desorption efficiency to most of metal ions except Zr(IV) ion. Also, desorption and recovery of Zr(IV) ion were successfully performed with 1M $H_2SO_4$. Recovery of trace amount of U(VI) ion from artificial sea water was over 94%. The chelating resin, XAD-16-TAO was successfully applied to group separation of rare earth metal ions from U(VI) by using 2M $HNO_3$ as an eluent.

• Environmental Analysis Health and Toxicology
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• v.14 no.4
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• pp.155-163
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• 1999

Heavy metal accumulation in living organisms through food-wed can give serious damage on physiological responses for vital activities. The initiation of heavy metal supposed to begin from the bio-accumulation of plants. To establish basic data fur heavy metal contents in plants at the area without artificial contamination, both woody and herb plants at Mt. Kwang-Duk were studied. The content of heavy metals in various organs of plants were analyzed by ICP. The range of heavy metals in plants for Al, As, Cd, Co, Cr, Cu, Fe. Mn, Pb, Se and Zn were 1.019∼257.200ppm, O∼2.929ppm, 0∼0.079ppm, 0∼0.054ppm, 0.023∼3.007ppm, 0∼1.997ppm, 2.031∼148.500ppm, 1.069∼51.320ppm, O∼126.900ppm, 0.708∼4.927ppm and 0.846∼4.949ppm, respectively. The amount of heavy metals in plants are much less than that of soil except some species. In woody plants, it was detected that the metal contents of leaves were higher than that of stems especially in case of Al and Fe with statistical significance. There were significant differences between shoots and roots of herb plants in metal content of Al, Co and Fe. Those metals have more accumulated in roots comparing with shoots. Some species of plants had shown the difference tendency of heavy metal accumulation. Generally, most species had not exceeded over twice of mean value each other, and had various difference according to the kinds of heavy metals.

• Applied Chemistry for Engineering
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• v.5 no.1
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• pp.149-159
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• 1994

The kinetics and equilibrium of metal extraction by benzamidoxime and phenylacetamidoxime-chloroform were investigated to apply amidoxime to metal extraction as chelating agent. The overall extraction constant extraction mechanism and selective extraction of copper were examined from the relation among extraction ratio, hydrogen ion concentration and extractant concentration. The experimental rate equation of copper extraction coincided with the theoretical rate equation and was expressed as $R_o=k{\overline{C}}_{HRo}(C_{Mo}/C_{Ho})^{1/2}$. The chemical species extracted was found to the type of ${\overline{CuR_2}}$.

• Economic and Environmental Geology
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• v.30 no.6
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• pp.553-566
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• 1997

Origin, behavior and enrichment of environmental toxic elements from the Deokpyeong area were investigated on the basis of major, trace and rare earth element geochemistry. Coaly metapelites of the Deokpyeong area are subdivided into grey phyllite, dark grey phyllite, coaly slate and black slate, which are interbedded along the Ogcheon Supergroup. The coaly slate had been mined for coal, but mining is closed. The coaly and black slates are lower contents of $SiO_2$ and $Al_2O_3$, and higher contents of LOI, CaO, $Na_2O$ and BaO as compared with the phyllitic rocks. Rare earth elements are highly enriched in the coaly and black slate. Average compositions (ppm) of minor and/or environmental toxic elements in the coaly and black slate are revealed as As=127, Ba=30,163, Cd=18, Cr=740, Cu=84, Mo=378, Pb=43, Sb=12, Se=44, U=144, V=8,147 and Zn=292, which are extremely high concentrations than those in the NASC compositions. Major elements (average enrichment index; 5.34) in the coaly metapelites are mostly depleted, excepting $P_2O_5$ and BaO, normalized by NASC. Rare earth elements (average enrichment index; 1.48) are enriched in the coaly slate. On the basis of NASC, minor and/or environmental toxic elements in the coaly metapelites were strongly enriched of all the elements with the exception of Co, Cs, Ni and Sr. Average enrichment index of trace elements in coaly metapelite is 31.51 (coaly slate; 51.94 and black slate; 15.46). Especially, enrichment index of potentially toxic elements (As, Ba, Cr, Cu, Mo, Ni, Sb, Se, U, V and Zn) of the rock is 46.10 (grey phyllite; 7.15, dark grey phyllite; 4.77, coaly slate; 88.96 and black slate; 22.11). These coal formations were deposited in basin of boundary between terrestrial and marine environments deduced to carbon, sulfur (C/S=2.2 to 275.7), trace and rare earth elements characteristics. Irregular behavior and dispersion between major, minor and rare earth elements of those metapelites indicates a variable source materials, incomplete mixing of differential source and/or reequilibrium of diagenesis and metamorphism.