• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.234-239
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• 2015

Various leaching tests were applied to the soil affected by accidental leakage of HF in an industrial area in Korea. Three different leaching methods including pH-stat, continuous batch leaching, and column tests were adopted to assess leaching characteristics and mobility of fluorine(F) in soil and the potential risks to ecosystem. Both natural and spiked samples were used for the leaching tests. F concentrations in the batch tests increased by leaching rapidly in the early stage of leaching and then maintained rather constant levels. Column leaching test also show similar result to that of the batch test. pH also controlled the leaching behavior of the soil. With increasing pH, more F was released in the pH-stat test. This is mainly due to the competition and exchange with hydroxyl ions, as pH increase to the alkaline range. Most of the F released by the accident seem to have removed in the very early stage of leaching, whereas some natural proportion from soil minerals are thought to have been released very slowly. Therefore, little F released during the accident remained, based on the results of this study on the samples after two years of the accident. We could conclude that soil contaminated by external effects such as chemical accidents should be managed immediately, especially with F.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.252-257
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• 2000

연구 결과를 간단히 요약하면 다음과 같다. 1) 온천 목적으로 개발된 국내 심부 암반 지하수(조사 대상 시료수 419개)는 화강암 및 화강편마암 지역에서 가장 높은 불소 함량을 보이며, 최소 75% 이상의 시료에서 먹는 물 수질 기준을 초과하였다. 2) 화강암 및 화강편마암 지역의 심부 지하수 내 불소 함량은 특히 Na-HCO$_3$ 유형의 지하수에서 높게 나타났는데, 이 유형의 지하수 수질은 사장석, 흑운모를 위시한 규산염 광물의 비조화 용해 반응에 의해 조절된다 이들 지하수는 비교적 깊은 관정심도를 나타내었다. 3) 백악기 화강암과 물과의 용출 반응 실험 결과, 전암 분말과의 반응에서는 최대 7 mg/l의 불소가, 흑운모의 용출 실험에서는 최대 35 mg/1의 불소가 용출되었다. 형석의 포화지수는 비교적 반응 초기에 침전 조건에 근접한 반면, 흑운모의 포화지수는 지속적으로 용해 조건에 놓여 있음을 확인하였다. 따라서, 국내 화강암 지역 심부 지하수 내의 불소는 대부분 흑운모의 비조화 용해 반응에 의해 용출되며, 용출 이후에는 형석의 용해/침전 평형 반응에 의해 그 농도가 조절되는 것으로 확인된다. 4) 앞으로, 보다 자세한 평형 열역학적 해석과 다른 이온종과의 상호 관계 규명 및 광물학적 검토를 통하여 불소의 기원과 거동에 관한 보다 정확한 해석을 시도할 계획이다.

• Proceedings of the KAIS Fall Conference
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• 2002.11a
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• pp.306-308
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• 2002

원자로냉각재계통(Reactor Coolant System) 및 사용 후 저장조정화계통(Spent Fuel Pool Purification System)에는 양ㆍ음이온 교환수지가 충진된 혼상 이온교환수지탑을 설치하여 계통수에 존재하는 방사성 핵종을 제거하고 있으며, 정화율을 나타내는 제염계수(Decontamination Factor)가 특정값 이하이면 수지를 교체하고 있다. 그러나 특정 핵종에 대한 제염계수가 수지 사용기간에 관계없이 기준값 이하로 나타나고 있고, 수지탑의 성능을 예측하고 있지 못하는 실정이다. 원자력발전소 1차 계통에 설치되어 불순물을 제거하는 이온교환 수지탑에 대한 연속화학평형모델에 적용한 결과 수지탑에서 이온 용출은 수지에 대한 이온 선택도 순서와 동일하고 냉각재계통에는 붕산이 주성분이므로 음이온수지에서 붕산이 가장 먼저 누출된다. 그리고 붕산으로 포화된 음이온수지의 음이온 불순물 제거능력은 저하되지 않으며, 리튬으로 포화된 양이온수지의 양이온 불순물 제거능력은 저하된다.

• Journal of the Korean GEO-environmental Society
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• v.7 no.4
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• pp.35-41
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• 2006

This paper analyzed elution and ingredients of soil components which consist of soil and rocks in 6 regions in Yeongyang and Cheongsong to identify substantial matters that cause muddy water in Imha reservoir. We identified that more than 80% of major ingredients in collected soil and rocks are vermiculite(V), illite(I), kaolinite(Ka), quartz(Q), feldspar(F). Sodium and calcium are eluted in large quantities from soil of Sanseong and Cheongki. When calcium is in contact with water, much ions are eluted rapidly. We confirmed these ions are alkali minerals rising pH. We consider clay components distributed in Yeongyang as major cause of muddy water and rising pH of Imha reservoir because its ingredient calcite easily is dissolved in rainwater and splits other mineral particles into ${\mu}m$ sized particles.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.116-126
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• 2015

The present study utilized a shuttle mechanism of wet chemical absorption using MEA. In addition, industrial by-products containing a large amount of inorganic alkali substances were utilized for wet carbonization process. Chemical pretreatment of industrial by-products extracted calcium ions. ICP result of calcium ion was obtained up to 17,900 ppm(17.9%) by acidic substance. And also, In this work, 94% of recovery rate was obtained using wet MEA absorption process from $CO_2$ flow at the ambient condition. Through the liquid carbonation process, a sludge was fixed with rate of 0.175 mg of $CO_2$ per mg of sludge. It was found from XRD results that the structure of final product was composed of a calcite structure which is general structure of $CaCO_3$.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.1
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• pp.111-116
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• 2010

The treatment of heavy metal, in the waste ash from incinerator and mine solid waste, by using alkali-soluble acrylic copolymer emulsion, that is effective in the absorption of heavy metal has been studied. It seemed that alkali soluble acrylic copolymer emulsion was very effective in the absorption of Hg, Pb, Cd and Cu in this test. Also, eco-friendly thixotropic grout, using alkali soluble acrylic copolymer emulsion, that is effective in the absorption of heavy metal, for the recycling of waste ash from incinerator and mine solid waste has been tested. It was observed that waste ash could be used as a raw material of eco-friendly thixotropic grout mortar due to the effectiveness of alkali soluble acrylic copolymer emulsion in the fixation of heavy metals including $Cr^{6+}$ from waste ash in this test.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.190-197
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• 2000

Anions such as C $l^{[-10]}$ , N $O_3$$^{[-10]}$ , S $O_4$$^{2-}$, P $O_4$$^{3-}$, and organic anions, that do not become a part of the clay mineral crystal lattice, are of considerable interest in soils which are a potential sink caused by acid rain. In this paper, elution of native sulfate and breakthrough curves (BTC) were obtained from miscible displacement of non-specifically or specifically adsorbed anions through non-saturated or saturated Bt soil of Chungwon series. The shape and position of the BTC's could be affected by adsoprtion and ion exchange onto the soil particle surfaces. Measured BTC's for oxalic acid under unsaturated and saturated conditions showed that less pore volumes were required to displace the native S $O_4$$^{2-}$S from the soil column, and that maximum detection limit of oxalic acid reached earlier than under unsaturated. The retarded BTC's to the righthand side could be attributed by different adsorption behavior of each anion, although BTC's may be influenced by the smaller order of velocity change. The alternate breakthrough and elution curves show the rapid approach to the maximum detection limit of C/Co = 1, compared to progressive tailing of elution curve to reach to C/Co = 0. The probable explanation for asymmetric elution patterns for both anion is that the anion was selectively adsorbed on the positively charged soil surface from the solution passing in the soil column. On the other hand, the variations of pH in effluent showed that pH was increased to 7 in the first 6 pore volume and then gradually decreased to pH 4.

• Journal of the Korean Ceramic Society
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• v.39 no.8
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• pp.728-734
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• 2002

Stabilization behavior of Cr, Cd, Cu, Pb, Fe and Zn heavy metals in the EAF dust was investigated by adding EAF dust to clay or white clay, respectively, up to 50 wt% with 10 wt% intervals and sintering at temperatures between 200 and $1200^{\circ}C$ with $200^{\circ}C$ intervals with an aid of ICP-AES followed by TCLP test to evaluate heavy metal cation exchange capacity of the clay or the white clay. The clay or the white clay had a better Cr ion exchange capacity than that of zeolite. The TCLP leaching test for the sintered specimens showed that Cr and Fe were rarely detected for all the specimens and the concentration of Cd and Zn decreased with increasing sintering temperature and decreasing EAF dust contents respectively. When the clay or the white clay were mixed with EAF dust, cation exchange may occur between the clay and the EAF dust so that the first stabilization of the mixtures containing semistabilized heavy metals may happen. Stabilization of heavy metals in the ceramic bodies was further completed probably due to the eutectic reaction caused by the sintering of semi-stabilized mixtures. It was conceivable that the white clay rather than the clay may be a better stabilizer for the EAF dust containing heavy metals.

• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.24-31
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• 2004

A cold mix asphalt (CMA) treatment process was proposed as a tool to recycle soils contaminated with petroleum hydrocarbons. Experimental studies were conducted to characterize performances of the CMA process in treating soils contaminated with diesel or diesel compounds. From the screening experiments, it was found that performances of five types of asphalt emulsions that contained a cationic or an anionic or a nonionic surfactant were not substantially different. In consideration of higher affinity for soils and higher sorption coefficients obtained, an emulsion containing Lauryl Dimethyl Benzyl Ammonium Chloride (LDBAC) was selected as a promising asphalt emulsion for treating diesel-contaminated soils. When the asphalt emulsion LDBAC was applied to treat three compounds that originated from diesel, the removal efficiencies obtained in the order of decreasing efficiencies were as follows: docosane > pentadecane > undecane. Leaching experiments on the specimen formulated by the emulsion LDBAC found that the selected treatment method could treat soils with diesel concentrations as high as 10,000 mg/kg. Leaching of the diesel from the specimen was controlled by diffusion for the first four days and then leaching rate diminished substantially. The latter behavior was characterized as depletion, which represents that the contaminant released amounts to more than $50\%$ of the total amount of the contaminant that can be leached. The amounts of three diesel compounds leached from the specimen in the order of decreasing amount were undecane, pentadecane, and docosane. The curing of the soil contaminated with pentadecane was relatively slow.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.137-137
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• 2012

인공관절은 노인성 질환이나 자가 면역질환, 신체적인 외상 등으로 인하여 발생하는 관절의 손상 부위를 대체하기 위하여 고안된 관절의 인공 대용물이다. 인공 관절 중 인공 고관절의 경우 라이너(Liner)와 헤드(Head) 부분이 직접적인 마모 운동을 수행하게 되므로, 이 부분의 소재 특성에 따라 인공관절의 수명이 결정 되게 된다. 현재 헤드 소재로서는 Co-Cr-Mo 합금이, 라이너 소재로서는 고분자 소재인 UHMWPE (Ultra High Molecular Weight Polyethylene)가 주로 사용되고 있다. 이러한 MOP (Metal-On-Polymer) 구조의 인공관절의 경우, 충격흡수의 장점이 있는 반면, 관절 운동시 발생하는 UHMWPE 의wear debris에 의해 골용해가 발생하게 되어 인공관절의 수명이 저하되는 문제점이 있으며, 금속 헤드의 마모로 인한 금속이온의 용출은 세포 독성의 문제를 야기하여 인공관절의 수명을 저하시키는 또 다른 원인이 되고 있다. 따라서 본 연구에서는 PIII&D (Plasma Immersion Ion Implantation & Deposition) 공정을 이용하여 금속 (Co-Cr-Mo 합금)소재 위에 세라믹 (niobium nitride) 박막을 증착하여 상대재인 UHMWPE의 마모를 줄이고자 하는 연구를 진행하였다. 금속 소재 위에 증착된 세라믹 박막은 상대재인 UHMWPE의 마모량을 줄여줄 뿐만 아니라 금속이온의 용출을 막아준다는 장점이 있으나, 장시간의 마모 운동에 의하여 발생하는 박막의 박리 현상은 인공관절의 수명을 급격히 저하시키는 또 다른 원인이 된다. 이러한 단점을 해결하기 위하여, 박막의 증착 초기에 이온주입과 증착을 동시에 수행하는 dynamic ion mixing공정을 수행하였다. Dynamic ion mixing 공정을 수행함에 따라 박막과 금속 사이의 접착력이 증가하게 되어, UHMWPE의 마모량이 2배 가까이 감소하는 것을 확인할 수 있었으며, 장시간의 마모시험에서도 우수한 결과를 얻을 수 있었다. 또한 UHMWPE의 마모량을 감소시키기 위하여 박막을 증착하기 전에 금속 소재에 질소 이온주입을 수행하는 pre-ion implantation 공정을 도입하였다. 질소 이온주입 결과 Co-Cr-Mo 합금 표면에 부분적으로 CrN, Cr2N의 세라믹 상이 형성 되는 것을 확인할 수 있었으며, 그에 따라 UHMWPE의 마모량이 2배 이상 감소 되는 것을 확인 할 수 있었다.