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        검색결과 1,677

        1425.
        2006.09 KCI 등재 서비스 종료(열람 제한)
        경상남도 고성군에 위치한 삼산제일 삼봉 동광산 주변지역의 중금속 오염현황을 조사하기 위하여 하천수와 하상퇴적물을 채취하여 화학적 분석을 수행하였다. 이와 더불어, 중금속 오염도와 환경위해성을 평가하기 위하여 왕수분해법과 연속추출법을 이용하여 분석된 하상퇴적물 내 중금속의 총 농도와 화학적 존재형태에 따른 농도를 바탕으로 한 오염지수와 위험지수를 산정하였다. 삼봉광산 지역보다는 삼산제일광산 지역에서 중금속 오염도도 높게 나타났을 뿐만 아니라 그 환경위해성도 훨씬 심각한 것으로 밝혀졌다. 이렇게 두 지역에서 오염현황, 오염도, 환경위해성 등이 다르게 나타나는 이유는 갱내수와 같은 광산 오염원의 존재여부와 지질학적 특성에 기인하는 것으로 사료된다. 삼산제일광산 지역의 경우 산성광산배수가 지속적으로 유출되어 하류 수계로 유입되고 있기 때문에 갱내수가 존재하지 않은 삼봉광산지역보다는 하류 수계에 대한 중금속 오염이 보다 더 악화되어 나타나는 것으로 보인다. 또한, 삼산제일광산 지역 주변 지질은 주로 안산암질 암류로 이루어져 있는데, 이들 안산암질 암류 내에는 산성광산배수를 중화시킬 수 있는 pH 완충력이 큰 탄산염 광물 등의 함량이 크지 않기 때문에 수계에서 중금속 오염이 자연적으로 정화되는 정도가 상대적으로 낮은 것으로 보인다. 이에 비해, 삼봉광산 지역의 지질은 방해석과 같은 탄산염 광물을 다량 함유한 화산쇄설성 퇴적암층인 고성층으로 이루어져 있어서, 이들 탄산염 광물들에 기인한 높은 pH 완충력에 의하여 중금속 오염이 하류 수계 방향으로 확산되지 못하는 것으로 판단된다.
        1426.
        2006.08 KCI 등재 서비스 종료(열람 제한)
        Hydrobromic acid salts of new N, N, O tridentate ligands containing phenol, 2-[(2-Methylamino- ethylamino)-methyl]-phenol(H-MMP․2HBr), 5-Bromo-2-[(2-Methylamino-ethylamino)-methyl]-phenol (Br- MMP․2HBr), 5-Chloro-2-[(2-Methylamino-ethylamino)-methyl]-phenol(Cl-MMP․2HBr), 5-Methyl-2-[(2-Methylamino- ethylamino)-methyl]-phenol(Me-MMP․2HBr), 5-Methoxy-2-[(2-Methylamino-ethylamino)- methyl]-phenol(MeO- MMP․2HBr) and 1-[(2-Methylamino-ethylamino)- methyl]-naphthalen-2-ol(Nap- MMP․2HBr) were synthesized. The synthesized ligands were confirmed by C. H. N. atomic analysis, UV-visible and IR spectroscopies, 1H NMR, 13C NMR and mass analysis. The potentiometry study revealed that the proton dissociation constants(logKnH) of the synthesized ligands and stability constants (logKML, logKML2) of transition metal complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) ions occurred in three steps and the order of the calculated overall proton dissociation constants(logβp) and stability constants (logKML) of ligands was Br-MMP․2HBr < Cl-MMP․2HBr < H-MMP․2HBr < Nap-MMP․2HBr < Me-MMP․2HBr < MeO-MMP․2HBr. The order showed a similar trend to that of Hammett substituent constants(δp). The synthesized ligands usually form 2:1(ML2) complexes with transition metal ions. The order of the stability constants of each transition metal ions was Co(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II).
        1427.
        2006.06 KCI 등재 서비스 종료(열람 제한)
        금속 조합을 이용하여 배관내벽에 형성된 스케일의 제거 및 억제 가능성과 광물학적 특성을 연구하기 위하여 주사전자현미경, 방안실체현미경, 선회절분석, 스케일 제거실험을 실시하였다. 배관내벽에 생성된 스케일은 대부분 철광물로 구성되어있으며 약간의 Si와 Ca 광물을 포함하고 있다. 배관내벽의 스케일을 제거하는 데 내부 금속을 Mg, 외부금속을 황동으로 실험하였을 때 가장 좋은 효과를 나타낸다.
        1431.
        2006.04 KCI 등재 서비스 종료(열람 제한)
        Eight USA soils were used for this study. The purpose of this study is to illustrate the characteristics of metals in the soil based on the sequential extraction with increasing pH. Extracts were analyzed for metals by ICP-MS and for dissolved organic carbon(DOC). As the pH increasing, the DOC extracted in each increment initially decreased and reached the minimum at pH 3 and then increased substantially at higher pH values. According to the pH increasing, the extraction of Ca, Cu, and Zn were illustrated as L type. It was found that there were strong correlation between the extracted Fe and DOC(r=0.64~0.97).
        1432.
        2006.03 KCI 등재 서비스 종료(열람 제한)
        Electrokinetic technique was considered in removing arsenic from the abandoned mining tails. In order to estimate the removal characteristics of arsenic, the sequential extraction analysis and desorption experiment were carried out prior to the application of electrokientic process. The result of sequential extraction analysis indicated that the water soluble and exchangeable fraction, easily leachable to ground water, were very low as much as about 2.5% and the fraction except residual (38.3%), possibly extractable under very acidic or alkalic environment, was about 59%. In the result of desorption test using four different kinds of electrolytes, the mixture of citric acid and sodium dodecyl sulfate (SDS) showed the highest desorption efficiency as much as 77.3%. The removal efficiencies of arsenic from mining tailings by electrokinetic process under the different electrolyte environments were slightly low and resulted in the following order: citric acid + SDS (18.6%) > 0.1 NHNO3 (8.1%) > HAc (7.4%) > Distilled water(6.6%). Also, arsenic in soil matrix was moved favorably in the direction of anodic rather than cathodic region, which is opposite trend with cationic metal ions generally existing in soil, because anionic form of arsenic is dominated in acidic soil caused by the movement of acid front form anode.
        1433.
        2006.03 KCI 등재 서비스 종료(열람 제한)
        Oxidative TCE decomposition over TiO2-supported single and complex metal oxide catalysts has been conducted using a continuous flow type fixed-bed reactor system. Different types of commercial TiO2 were used for obtaining the supported catalysts via an incipient wetness technique. Among a variety of titanias and metal oxides used, a DT51D TiO2 and CrOx would be the respective promising support and active ingredient for the oxidative TCE decomposition. The TiO2-based CrOx catalyst gave a significant dependence of the catalytic activity in TCE oxidation reaction on the metal loadings. The use of high CrOx contents for preparing CrOx/TiO2 catalysts might produce Cr2O3 crystallites on the surface of TiO2, thereby decreasing catalytic performance in the oxidative decomposition at low reaction temperatures. Supported CrOx-based bimetallic oxide systems offered a very useful approach to lower the CrOx amounts without any loss in their catalytic activity for the catalytic TCE oxidation and to minimize the formation of Cl-containing organic products in the course of the catalytic reaction.
        1434.
        2006.02 KCI 등재 서비스 종료(열람 제한)
        To obtain the safety evaluation of the ginseng, residues of heavy metals in culture environment of ginseng on Punggi and Sangju, Kyeongbuk are surveyed. The concentration for component of ginseng on Punggi and Sangju were 14.12 mg/kg and 15.74 mg/kg, respectively. The concentration for general component such as crude fiber, ash, crude lipid, crude protein, carbohydrate, of ginseng were coincided between Punggi and Sangju. The concentration for As, Pb, Cd, and Hg in soil on Punggi were 14.24 ppb, 43.13 ppb, 8.73 ppb and 0.82 ppb, respectively. The concentration for As, Pb, Cd, and Hg in soil on Sangju were 19.20 ppb, 54.82 ppb, 15.90 ppb and 1.04, respectively. Residual heavy metals are not polluted in the soil with culture ginseng on Punggi and Sangju. The concentration for As, Pb, Cd, and Hg with ginseng on Punggi were 29.30ppb, 21.78 ppb, 1.32 ppb and 2.72 ppb, respectively. The concentration for As, Pb, Cd, and Hg with ginseng on Sangju were 3.22 ppb, 24.43 ppb, 1.44 ppb and 4.74 ppb, respectively. Also the detection concentration for As, Pb, Cd, and Hg in ginseng were also lower than the Korea Food & Drug Administration advisory level for heavy metal in herbal medicines. Residual heavy metals are not polluted in the ginseng on Punggi and Sangju at Kyeongbuk, Korea.