흡착 우라늄 이온의 전기 탈착거동

정종헌,원휘준,최왕규,김계남,이성호,오원진 한국공업화학회 2003 응용화학 Vol.7 No.1

Liquid wastes containing uranium ions in high concentration of chemical salts havebeen treated by electrosorption on a activated carbon fibers(ACFs) electrode. Effectiveuranium (VI) removal is accomplished when the potential is -0.5V(vs. Ag/AgCl) ormore negative. For a feed concentration of 100mg/1, the concentration of U(VI) in thecell effluent is reduced to less than 1mg/1, and electrosorption capacity over 500mg/uranium/gACF is reached. The adsorbed uranium can be desorbed up to 99%for 20h by passing a 1.9N NaCl solution at pH 3 through the cell and applying a potential of +1.2V. The amount of desorbed uranium increased as the solution pHwas lowered and the applied potential increased.

우라늄 오염 금속표면의 제염을 위한 UO_2 용해특성 연구

이성열,최왕규,오원진,유승곤 한국공업화학회 2003 공업화학 Vol.14 No.3

국내의 가동 중지된 우라늄 변환시설의 해체 시 대량으로 발생될 탱크류 및 배관 등 공정 계통 부품으로 이루어진 금속 폐기물의 재팔용 또는 자체처분을 위한 현장 제염기술로 질산 제염공정을 선정하였다. 오염 물질로써 UO_2를 대상으로 UO_2 입자의 용해 거동을 통해 우라늄 화합물로 오염된 금속 폐기물에 대한 질산 용액의 표면제염 적용성을 평가하였고, 우라늄 변환시설 내에서 직접 인출한 UO_2 오염 시편의 제염 실증실험을 통해 제염 공정의 성능을 검증하였다. 질산 제염 용액에서 UO_2 입자의 용해속도는 질산의 농도 및 용액의 온도에 크게 의존하였으며, 산화제로 H_2O_2를 첨가함에 의해서 상온의 저 농도 질산 제염 용액 내에서도 H_2O_2가 첨가되지 않은 경우에 비해서 속도가 현저하게 증가되었다 UO_2로 오염된 시편의 제염에 있어서, H_2O_2가 첨가되지 않은 질산 용액 내에서의 제염계수는 α 방사능에 대해서는 1.8~2.7, β 방사능에 대해서는 1.8~2.3인 반면에 질산 용액에 H_2O_2를 첨가한 경우에는 α 방사능에 대해서 61.7~338.5, β 방사능에 대해서는 20.1~92.4를 나타냄으로써 H_2O_2를 첨가함에 의해서 상온, 저농도 질산 용액 내에서도 UO_2 오염된 금속표면을 효과적으로 제염할 수 있음을 확인하였다. In this study, a decontamination process using nitric acid was selected as an in-situ technology for recycle or disposal of large amount of metallic wastes, which includes process system components such as tanks, piping, etc that are generated as a result of dismantling retired uranium conversion facility in Korea. The applicability of nitric acid solution for surface decontamination of metallic wastes that are contaminated with uranium compounds was evaluated through dissolution of UO_2 powder. The decontamination decontamination performance are verified using UO_2 contaminated specimen that came from an uranium conversion facility. Dissolution rate of UO_2 powder was dependant considerably upon nitric acid concentration and solution temperature. Notable enhancement of dissolution rate was achieved by addition of H_2O_2 as an oxidant even in the condition of low concentration of nitric acid and low temperature. The results for decontamination of the specimen contaminated with UO_2 showed that the decontamination factors (DFs) for nitric acid solution without H_2O_2 were 1.8~2.7 and 1.8~2.3 for α and β-radioactivity. respectively, while DFs for nitric acid solution containing H_2O_2 were 61.7~338.5 and 20.1 ~92.4 for α and β-radioactivity, respectively. Thus, the metallic surfaces contaminated with UO_2 can be decontaminated effectively with low concentration of nitric acid at mom temperature in the presence of H_2O_2.

Studies on Electrokinetic Remediation of Radioactively Contaminated Soil By Using Sulfuric Acid

Won-Zin Oh,Gye-Nam Kim 한국방사성폐기물학회 2004 방사성폐기물학회지 Vol.2 No.2

10년 이상 된 방사능오염 토양에서 동전기적 방법에 의한 Cs과 Co의 제염효율을 높이기 위해 HSO과 시트르산을 첨가제로 사용했다. 동전기 토양복원 컬럼의 방출수 평균속도는 2.0 cm/min이고, 10일 동안 방출된 토양폐액의 부피는 컬럼의 3.6 공극부피다. 10일간 Cs 의 제거효율이 54%에 불과한 반면에, Co는 97%나 제거되었다. 이것은 Cs의 흡착평형계수가 Co 보다 크기 때문이라고 생각된다. 본 연구에서 제시한 수학적 모델에 의한 컬럼 잔류 오염도는 실험 오차 범위에서 실험결과와 잘 일치하였다. H2SO4 and citric acid were used as additives for the electrokinetic remediation experiment to increase removal efficiency of Cs and Co from the radioactive soil waste stored for more than 10 years. The average effluent velocity discharged from the elctrokinectic remediation experimental column was 2.010 cm/min and the discharged soil wastewater volume for 10 days is 3.6 pore volume of the column. 97% of Co in the column was decontaminated for 10 days of operation, while only 54% of Cs was decontaminated. These results are considered that the absorption equilibrium coefficient of Cs is higher than that of Co. The predicted values of the residual concentration by the proposed mathematical model were well coincided with the experimental results within the experimental error range

Ag (Ⅱ) 매개체를 사용하는 전기화학적 매개산화에 의한 유기산 분해

오원진,이근우,최왕규,남혁 한국공업화학회 1998 응용화학 Vol.2 No.1

The mediated electrochemical oxidation (MEO) of organic acids such as EDTA and citric acid was carried out using Ag(II) as a mediator under constant current in order to develop a radioactive waste treatment process for the safe destruction of organic compounds at ambient temperature. Ultimate conversion efficienciy of 95∼97 % was obtained with EDTA and CA due to the transportation of some of organic substrates to the catholyte across the cation selective membrane during the MEO. Organic substrates remaining in the anolyte, however, could be completely destoryed to form carbon dioxide and water by the reaction with electro-generative Ag(II). With increasing temperature, slight increase in the coulombic efficiency on the MEO of EDTA and CA was observed. Relatively small effect of temperature implies that the MEO using Ag(II) as a mediator can be used effectively for the safe destruction of toxic or hazardous organic wastes at ambient temperature.

Chromium(3)Oxide 의 용해반응 특성 연구

오원진,최왕규,박헌휘 한국화학공학회 1987 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.27 No.6

가압경수로 일차계통내에 생성되는 부식 산화물중 약 40%를 차지하는 크롬산화물은 산화적 용해방법에 의해 제거될 수 있다. 본 연구에서는 저농도 화학제인 NP(Nitric Acid/Permanganate)방법에 의한 Cr₂O₃의 용해반응 특성을 bulk상의 농도와 온도조건이 일정하게 유지된 회분식 용해조에서 Cr₂O₃입자를 사용하여 살펴보았다. Cr₂O₃입자의 용해반응은 반응 생성층을 통한 확산지배의 "unreacted-core shrinking model"로 실험 오차 범위내에서 잘 나타낼 수 있으며 실험 범위내에서 반응 속도상수는 bulk상 MNO₄^- 농도에 반비례하였고, 수소이온 농도와 온도에 비례하였으며, 용해반응속도식은 다음과 같은 실험식으로 정량화할 수 있었다. K_Dt=1-3(1-X)^⅔+2(1-X) K_D=6.1×10^(-3) exp(-2470/T) [Mno^-₄]^(-1.23)[H^+]^(0.5) Chromium oxide, amounting to about 40% of the total corrosion oxides formed within the primary coolant system of Pressurized Water Reactor, can be removed by an oxidative dissolution. The study of dissolution reaction of chromium(III) oxide was carried out with a stirred batch-type dissolver under constant concentration and temperature of bulk phase during the reaction using relatively small amount of chromium(III) oxide particles and dilute nitric acid/permanganate solution. An unreacted-core shrinking model with ash diffusion control was found to predict the dissolution behaviour of chromium(III) oxide particles satisfactorily in the experimental error range. Overall dissolution reaction rate constant of the above model, K_D, being inversely proportional to the bulk phase MnO^-₄ concentration while being proportional to hydrogen ion concentration and temperature, was expressed by the following experimental correlation within the experimental range. K_Dt=1-3(1-X)^⅔+2(1-X) K_D=6.1×10^(-3) exp(-2470/T) [Mno^-₄]^(-1.23)[H^+]^(0.5)

Co(2) , Sr(2) , Cs(1) 이온의 전기적 분리 특성

오원진,유재형,정종헌,이상문,문제권,원휘준,김계남 한국공업화학회 2000 응용화학 Vol.4 No.1

The electrosorption process using an ACF felt electrode was confirmed to be effective in the removal of Co(II), and an ACF felt electrode could be continuously used in the purification of liquid waste. The separation methods of Co(II), Sr(II), Cs(I) in binary, ternary systems could be obtained. The electrosorption process, without producing secondary wastes, appears to be a promising separation technique for various metal ions in liquid waste treatment.

Fixation of $\gamma$-Radionuclides by the PVA-PMAA System

Won, Hui-Jun,Ahn, Byung-Gil,Jung, Chong-Hun,Kim, Gye-Nam,Oh, Won-Zin Korean Nuclear Society 2000 Nuclear Engineering and Technology Vol.32 No.3

A series of laboratory experiments was conducted to investigate the fixation characteristics of poly(vinylalcohol)-poly(methacrylic acid)(PVA-PMAA) mixed solution on the soluble ${\gamma}$- radionuclides. Using the potentiometric titration technique, it was found out that the PVA and PMAA in a solution form intermacromolecular complex. The mobilized portion of each radionuclide by water from sand surface treated with a fixative was measured by ${\gamma}$-ray spectroscopy. The mobilized portion of minor radionuclides such as 241Am, 154Eu, 155Eu and 144Ce were higher than those of 134Cs and 137Cs. The capability of PVA-PMAA system was better among the candidate solutions for the fixation of total ${\gamma}$-radioactivity. 134,137Cs which is composed of more than 85 % of total ${\gamma}$-radioactivity could be fixed effectively by the PVA-PMAA solution.

제올라이트를 함유한 부분활성화된 PAN복합체 섬유의 제조에 관한 연구

오원진,설용건,정경택,문제권,황덕근,이화섭 한국화학공학회 1998 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.36 No.5

아크릴로니트릴모노머를 전구체로하여 제올라이트를 함유한 부분활성화 PAN 복합체 섬유를 제조하였다. 중량평균 분자량 630,000이고, 다분산지수가 1.30인 방사 dope를 건습식 방사법(dry-jet wet spinning technique)으로 방사하였다. 제올라이트를 함유한 35-40㎛ 두께의 PAN섬유는 건습열 연신과정을 통해 배향도가 증가되었다, 같은 조건에서 얻어진 PAN섬유에 비하여 제올라이트를 함유한 PAN 복합체 섬유는 89%의 인장강도를 나타내었다. 고리화와 부분활성화 상태는 적외선분광 분석법과 X선회절 분석법을 이용하여 확인하였다. PAN 섬유의 부분활성화 이후에도 제올라이트의 함유에 따른 특성 피이크를 X선회절 분석법을 이용하여 확인할 수 있었다. 제올라이트를 함유한 PAN 복합체 섬유는 새로운 유무기 복합 흡착제로 사용을 기대할 수 있을 것으로 사료된다. Partially activated polyacrylonitrile(PAN) composite fiber containing zeolite particle was prepared by using acrylonitrile(AN) as a precursor. Weight average molecular weight(Mw) and polydispersity index of spinning dope was 630,000 and 1.30 respectively. Dry-jet wet spinning technique was used for making PAN composite fiber. During, the dry-jet wet spinning process, PAN composite fiber of 35-45㎛ in diameter shows increased orientation. Initial elastic modulus of PAN composite fiber containing zeolite particles was 89 % of PAN fiber at the same experimental condition. The cyclization and activated state of PAN fiber were conformed by Fourier transform infrared(FT-IR) spectroscopy and X-ray diffraction(XRD). After the activation process, characteristic peaks of PAN composite fiber could be observed due to the incorporation of zeolite particles from XRD. Partially activated PAN composite fiber containing zeolite particles is expected to use as an organic-inorganic composite absorbent.

전기 흡 탈착공정에 대한 매개변수의 영향

오원진,이상문,문제권,이성호,정종헌 한국공업화학회 1999 응용화학 Vol.3 No.2

The potential dependent adsorption of cobalt ions present in trace amounts in liquid waste is studied using an activated carbon fibers(ACF) as an electrode. In this study, the effect of parameters on the electrosorption was investigated. The parameters are concentration of electrolyte, appling potential and current, contact time, and the amount of ACF used as an electrode.

EDTA 농도 , pH 및 온도가 코발트 오염토양의 제염효과에 미치는 영향

원휘준,권회삼,안병길,김계남,이병직,이계호,오원진 한국공업화학회 1998 응용화학 Vol.2 No.2

In order to decontaminate the soil contaminated with ^(60)Co ion, a series of preliminary experiment was conducted. Decontamination characteristics of EDTA at various [EDTA], pH, and different temperature were investigated using the soil artificially contaminated with Co²^+ ion. And, the effect of dissolved iron ion on the decontamination performance of Co²^+ ion was also investigated.