• 통합자연과학논문집
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• 제4권2호
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• pp.130-136
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• 2011

This study investigated the adsorption characteristics of nickel, zinc and cadmium ions from the aqueous solution onto the alginate bead. Adsorption equilibrium capacities of the heavy metal ions increased with increasing initial pH of the solution. The adsorption equilibrium isotherm of the heavy metal ions was well represented by Langmuir equation. The magnitude of adsorption capacity of the heavy metal ions onto alginate bead was the order of cadmium > zinc > nickel. Kinetic parameters were measured in a batch adsorber to analyze the adsorption rates of the heavy metal ions. The internal diffusion coefficient of the heavy metal ions in the intraparticle were determined by comparing the experimental concentration curves with those predicted from the surface diffusion model (SDM) and pore diffusion model (PDM). The internal diffusion of the heavy metal ions in the intraparticles was explained by PDM.

• 한국군사과학기술학회지
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• 제13권5호
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• pp.769-774
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• 2010

It happened fractures on special bolt which supported main landing gear actuator up-lock rod of aircraft. Cracks were initiated mainly from the center hole and the external thread of the special bolt. To find out failure root causes, metallographic, fractographic analyses as well as test work were carried out. From the fractographic study by SEM work, fracture occurred by a brittle intergranular type failure. The fracture could be occurred primarily by solid-metal-induced embrittlement due to cadmium embrittler penetrated into the flaw existed after machining work for center hole and thread on the bolt during baking treatment processing to eliminate hydrogen. For its successful application, cadmium EP bolts require proper and adequate baking treatment after electroplating, and make no more drilled center hole on the bolt to prevent same failure.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.91-96
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• 2001

Restoration of contaminated soils to an environmentally acceptable condition is important. One of the newer techniques in soil remediation is a method based on electrokinetic phenomena in soils. The technology uses electricity to affect chemical concentrations and water flow through the pores of soils. An important advantage of electrokinetic soil remediation over other in-situ processes such as soil flushing is the capability of control over the movement of the contaminants. Because the migration of the contaminants is confined by the electric field, there is little dispersion outside the treatment zone. Furthermore, the process is effective for soils with low and variable permeability. In the present study, the distributions of cadmium in the electrokinetic processing of kaolinite under the condition of constant applied voltage are investigated. Cadmium accumulates near the cathode without reducing the diffusion of hydroxide ion into the soil. In keeping the catholyte pH at neutrality, cadmium migrates toward the cathode without any accumulation of cadmium near the cathode and is successfully removed at the cathode reservoir. It was also found that the progress of electrokinetic processing of cadmium could be gasped to a certain extent by monitoring the local voltage and the current density.

• Journal of Preventive Medicine and Public Health
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• 제16권1호
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• pp.25-30
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• 1983

This research is to examine the detoxication effect of methionine on cadmium intoxication For this purpose, this paper provides an analysis of the data on the groups of mice (ICR), one group of mice treated with 40 ppm of cadmium only. and other groups of mice combined-treated with cadmium and 0.1%, 0.25%, 0.5% and 1% methionine. After breeding for 40 days, the data on the growth of mice, changes in activation of alkaline phosphatase in blood, and the cadmium content in the liver and kidney, are analysed. The results were as follows: 1) The growth-rate of mice, in the cadmium only injected group, was declined by 9% in comparison with the control group after 40 days. But the two groups of cadmium with 0.5% and 1% methionine showed the rise of 9% ana 14% respectively above the growth-rate of the control group. The results from the groups of cadmium with 0.1% and 0.25%, methionine were similar to that from the cadmium only injected group. 3) Changes in activation of alkaline phosphatase in blood decreased to 86.45% in the cadmium only injected group behind the 100% activation of the control group. The groups of cadmium with 0.1% and 0.25% methionine showed no difference with the former group. But the groups of cadmium with 0.5% and 1% methionine recovered to the 93.14% and 96.08% of activation respectively. 3) The mean content of cadmium in the liver was $0.028{\pm}0.001{\mu}g/g$ in the control group. The cadmium only injected group showed the mean cadmium content of $2.80{\pm}0.62{\mu}g/g$ in the liver, which was similar to $2.82{\pm}1.03{\mu}g/g$ in the group of cadmium with 0.1% methionine, and $2.56{\pm}0.77{\mu}g/g$ in the group of cadmium with 0.25% methionine. But the groups of cadmium with 0.5% and 1% methionine showed the reduction of cadmium contents in the liver to $1.84{\pm}0.56{\mu}g/g$ and $1.74{\pm}0.35{\mu}g/g$ respectively. In the kidney, the groups of cadmium with 0.1%, 0.25% and 0.5% methionine shelved the similar cadmium content to the group treated with cadmium only. But the group of cadmium with 1% methionine showed a small increase to $4.13{\pm}1.00{\mu}g/g$ in comparison with the group treated with cadmium only. This analysis proves that the mobility and diffusion of cadmium in tile tissues advance faster ill the group treated with cadmium and methionine than in the group treated with cadmium only.

• Nuclear Engineering and Technology
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• 제47권5호
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• pp.588-595
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• 2015

This study presents an effective method for additional recovery of residual actinides in liquid electrodes after the electrowinning process of pyroprocessing. The major distinctive feature of this method is a reactor with multiple reaction cells separated by partition walls in order to improve the recovery yield, thereby using the interelement difference in diffusion coefficients within the liquid electrode and controlling the selectivity and purity of element recovery. Through an example of numerical simulation of the diffusion scenarios of individual elements, we verified that the proposed method could effectively separate the actinides (U and Pu) and rare-earth elements contained in liquid cadmium. We performed a five-step consecutive recovery process using a simplified conceptual reaction cell and recovered 58% of the initial amount of actinides (U + Pu) in high purity (${\geq}99%$).

• 방사성폐기물학회지
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• 제8권1호
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• pp.1-7
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• 2010

본 연구에서는 LiCl-KCl/Cd계의 전해제련 공정을 대상으로 악티늄 및 희토류족 원소들의 전해이동을 모델링하고 해석하였다. 이 공정에서 용융염 전해질과 액체 카드뮴 음극간의 확산 경계층 계면에서 확산제한 전기화학반응 및 물질수지를 고려한 단순화된 동적모델을 수립하였다. 제안된 모델링 접근방법은 음극에서 일어나는 금속염의 반쪽 전지 환원반응에 기초를 둔 모델이다. 이 모델을 사용하여 정전류 전해공정에서 주어진 인가전류 조건을 만족하는 시간까지의 전해이동과 연계된 농도거동, 각 원소의 패러데이 전류 그리고 시간 함수의 전기화학 전위를 예측하는 가능성을 보여주었다. 선택된 5성분 원소(U, Pu, Am, La, Nd)계의 결과를 예비 모사하여 전산모델이 전기화학적 특성을 이해하고 개선된 전해제련로를 개발하기 위한 정보를 제공할 수 있는가를 평가하였다.

• 한국지반환경공학회 논문집
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• 제3권1호
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• pp.13-26
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• 2002

본 연구에서는 아연 및 카드뮴의 확산계수에 미치는 온도영향에 대한 연구를 위해 $15^{\circ}C$와 $55^{\circ}C$에서 확산실험을 수행하였다. 온도변화에 따른 유효확산계수의 변화를 비교할 경우 두 금속 모두에서 $55^{\circ}C$에서의 유효확산계수가 $15^{\circ}C$에서의 확산계수에 비해 최대 10배까지 큰 것으로 나타났다. 그리고 온도증가에 따른 확산속도의 증가와 더불어 중금속들의 흡착량 또한 증가하는 것으로 나타났다. 그러므로 지연인자를 얻는 방법의 차이에 따라 비교적 흡착량을 과다하게 평가하는 흡착실험을 통해 얻은 지연인자를 이용하여 유효확산계수를 산정할 경우 확산계수를 과대평가 할 수 있다. 그리고 연속추출 실험 결과, 아연의 경우에는 탄산염 형태로의 분배경향이 가장 크게 나타났고, 카드뮴의 경우에는 이온교환형태로의 분배가 가장 크게 나타났다. 특히 실험을 수행한 온도가 증가함에 따라 아연 확산실험의 경우에는 탄산염 형태와 유기물 형태로의 분배가 증가하는 것으로 나타났다. 반면 카드뮴 확산실험의 경우에는 온도변화와 무관하게 60%이상이 이온교환 형태로 분배됨을 알 수 있었다.

• 한국지반공학회논문집
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• 제24권6호
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• pp.17-25
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• 2008

폐금속 광산 지역 등지에서 중금속으로 오염된 지하수의 정화 및 오염확산 방지를 위하여 투수성 반응벽체를 사용 할 수 있다. 본 연구에서는 슬래그가 투수성 반응벽체 충진물질로서 적당한지 평가하기 위하여 폐광산 지역에서 문제가 되고 있는 몇 가지 중금속(i.e., Pb, Cu, Cd)에 대한 슬래그의 반응성을 평가하였다. 폐광산 지역 지하수에는 중금속류들이 복합오염의 형태로 존재하며, 음이온 물질인 황산염, 탄산염 등도 공존한다. 중금속으로 오염된 현장의 조건을 고려하여, 1) 중금속 종류에 따른, 2) 초기 농도에 따른, 3) 음이온(황산염)의 존재에 따른 영향을 회분식 실험을 통하여 슬래그의 흡착능을 평가하였다. 슬래그의 흡착특성은 등온흡착평형(equilibrium sorption)과 동적인 흡착(kinetic sorption)인 경우 각 조건에 따른 영향을 확인하였다.

• 대한화학회지
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• 제31권5호
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• pp.444-451
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• 1987

에틸렌디아민, 프로필렌디아민 및 디에틸렌트리아민의 구리(II), 카드뮴(II) 및 아연(II)착이온의 桓元에 대하여 압력에 따른 폴라로그래피적 파라미터의 依存性을 조사하였다. 水銀滴下電極, 고인수은전극 및 나선형 백금선을 각각 作業電極, 基準電極 및 補助電極으로 사용하였다. 압력이 1기압에서 1,500기압으로 증가함에 따라 금속착이온의 還元半波電位는 陰電位 쪽으로 이동하였으며, 擴散電流는 상당히 커졌다. 이러한 현상은 전해질용액의 물리적 성질 곧 密度, 粘性度, 誘電常數, 電氣傳導度 등이 압력이 증가함에 따라 커지기 때문이다. 압력을 증가시키면 log plot의 기울기 값이 커지므로 환원반응의 可逆性은 나빠지고 있다. 25$^{\circ}$C ~ 35$^{\circ}$C의 온도범위에서 측정한 확산전류의 溫度係數가 압력을 증가시켜도 2%정도이므로 高壓下에서 폴라로그래피적 환원반응은 擴散支配的이다. 또 실험압력 범위내에서 금속착이온의 확산전류와 농도 사이에는 線形關係가 성립하였다.

• 한국환경보건학회지
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• 제19권2호
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• pp.46-54
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• 1993

This study was carried out on the stabilized/solidified treatment for the reducing leachability of hazardous heavy metals copper, lead, chromium and cadmium in the hazardous sludge which treated to be unleached heavy metals by sodium diethyl dithiocarbamate. Cement matrix was analyzed for the leachability of 24 hrs and dynamic leaching test, structure and the optimum condition for the stabilization and solidification of the hazardous sludge. In 28 days of curing time the unconfined compressive strength was 21.5 kg/cm$^2$ at the ratio of portland cement (0.5)+fly ash (0.25) and 23.5 kg/cmz at the ratio of portland cement (0.5)+fly ash (0.25) + cake (0.25). High concentration of Pb, Cr and Cd in the sea water and Cu in the distilled water were leached at the dynamic leaching test. The concentration of leaching heavy metals for specimens which were tested 24 hrs were found low leachability with decreasing pH of leachant. According to dynamic leaching test, the low level of copper, lead, cadmium and chromium were leached in the cement matrix with sodium diethyl dithiocarbamate. But the effective diffusion coefficient of unleached cement matrix which was treated sodium diethyl dithiocarbamate was decreased above 2 times than that of cement matrix. The relation of leachant renewal period (Y) and cumulative fraction ion leached (X) was the following regression equations. Solidification with unleached agent. Y$_{Cu}$ = 1413752X + 247, Y$_{Pb}$ = 223501IX + 214, Y$_{Cr}$ = 8310601X - 472, Y$_{Cd}$ = 168787X + 1061 The structure of' solidified matrix with X-ray diffraction analysis was composed more Ca(OH)$_2$, Si, Mg(OH)$_2$ and Al in the unleached cement matrix than those in cement matrix.