초록

□ Co와 Cs에 대한 황산화균의 내성 및 적용 가능성 평가
□ 황산화균을 활용한 토양 내 Co와 Cs의 용출제거 가능성 확인 후 최적조건 도출 중
□ 지표생물종 Eisenia Fetida를 활용한 부지환경평가 기초자료 확보

(출처 : 보고서 요약서 3p)

Abstract ▼

Ⅲ. Research Results
Soil sampling was carried out at the vicinity area from the NPP in Korea. The collected soil texture is mainly sand, which contained approximately 80% of SiO2, and the main elements were Al₂O₃ and K₂O. The collected soil was artificially contam

Ⅲ. Research Results
Soil sampling was carried out at the vicinity area from the NPP in Korea. The collected soil texture is mainly sand, which contained approximately 80% of SiO2, and the main elements were Al₂O₃ and K₂O. The collected soil was artificially contaminated using solution of Co(NO₃)₂·6H₂O and CsCl for bioleaching experiments.
The sulfur-oxidizing bacteria used in the bioleaching experiment induces oxidation of sulfur and reduction of pH in culture medium. The pH of medium decreased below 1.5 and SO₄^2- concentration increased up to 10 mg/L by the bacteria incubation for a month. The sulfur-oxidizing bacteria was identified a similar species with Acidithiobacillus thiooxidans (ATCC8085) that has 95% similarity by 16s rRNA analysis. Moreover, the bacteria could metabolize under 50 mg/L of Co exposure condition and regardless of Cs concentration.
In order to verify the bioleaching efficiency, the artificially contaminated soil was mixed with the bacteria for 50 days. The Co content in the soil was reduced by 98% from 0.582 mg to 0.009 mg; in addition, the Cs was reduced by 89% from 0.909 mg to 0.099 mg. Various experimental conditions were examined to optimize the bioleaching process. That are solid-liquid ratios, amount of S-powder and bacteria inoculum. The removal efficiency of Co and Cs from soil retained 90% and 80%, respectively regardless of the amount of S-powder and the amount of microbial inoculum, while, removal efficiency decreased when the solid-liquid ratio is below 5 mL/g. Na2S, S2O3, Cystine, and Glutathione were applied for an energy source of bacteria. In addition, alginate S-ball and solid block were assessed for the bacteria growth experiment. The bacteria cannot grow using various sulfur types except for the S-powder, however, alginate S-ball and solid S-block may applicable for their growth.
Environmental Assessment can be performed using the soil ecological toxicity assessment. In this study, we use earthworm species Eisenia petida. Earthworm exposure experiments were conducted in the artificially contaminated soil with Co and Cs. Uptake results from soil to earthworm indicated that accumulation of Co and Cs increased with respect the time and exposure concentration. Co accumulation concentration was 65.0±12.5 ug/g when exposed for 15 days in the soil with Co concentration of 50 mg/kg and Cs accumulation concentration was 51.17±10.77 ug/g when exposed for 15 days in the soil with Cs concentration of 50 mg/kg. In case of Co and Cs mix-contaminated soil, the accumulation concentration was reduced by 31.3% of Co and 55.7% of Cs. The Co and Cs extraction by different methods presents different leaching efficiency. TCLP extraction method showed a higher leaching amount of Co, and Mehnich3 was a higher leaching amount for Cs in the soil.

(출처 : SUMMARY 6p)

목차 Contents

• 표지 ... 1
• 제 출 문 ... 2
• 보고서 요약서 ... 3
• 요약문 ... 4
• SUMMARY ... 6
• CONTENTS ... 8
• 목차 ... 9
• 제1장 연구개발과제의 개요 ... 10
• 1-1절 연구개발의 목적 및 범위 ... 10
• 1-2절 연구개발의 필요성 ... 10
• 제2장 국내‧외 기술개발 현황 ... 12
• 2-1절 국내 기술동향 ... 12
• 2-2절 국외 기술동향 ... 13
• 제3장 연구개발 수행 내용 및 결과 ... 14
• 3-1절 원자력 발전시설 주변 부지의 Co와 Cs의 거동특성 평가 ... 14
• 3-2절 인위오염토양의 제조 ... 15
• 3-3절 황산화균의 배양 및 성장특성 평가 ... 16
• 3-4절 황산화균의 Co와 Cs에 대한 내성 평가 ... 17
• 3-5절 황산화균의 배양을 위한 에너지원인 황의 형태변화 ... 18
• 3-6절 미생물용출법을 활용한 토양 내 Co와 Cs 제거 ... 20
• 3-7절 미생물용출법의 최적화 방안 도출 ... 22
• 3-8절 원전해체부지 환경평가 기술 ... 24
• 제4장 목표달성도 및 관련분야에의 기여도 ... 36
• 4-1절 연구개발목표의 달성도 ... 36
• 제5장 연구개발결과의 활용계획 ... 37
• 제6장 참고문헌 ... 38
• 끝페이지 ... 39