Zinc ferrocyanide가 도입된 탄소나노튜브 자성복합 흡착제의 방사성 폐액 내 Cs 분리 특성과 HGM 흡착공정 적용성 연구 = A study of zinc ferrocyanide functionalized magnetic carbon nanotubes complex for separation of cesium ions from radioactive waste and High gradient magnetic adsorption column process application

다국어 초록 (Multilingual Abstract)

The design life of nuclear power plant is 30~40 year. Our country’s nuclear power plants have operated 50 years. Even considering the continued operation period, we should prepare and develop decontamination and decommissioning technology for nuclear facilities.
In particular, cesium ions from radioactive wastewater were classified hazardous material because of their high solubility and long half time. Insoluble metal ferrocyanide are well known for selective removal of alkali ions by cation exchange and has strongest affinity for cesium ions. Especially, zinc ferrocyanide has high affinity to cesium ions, relatively low solubility for water and not difficulty of desorption. However, there are some difficulties in using as adsorbents for process because they are very fine powder.
For enhancing separation efficiency of adsorbents after removal of cesium ions, compose magnetic carbon nanotube complex which functionalized with zinc ferrocyanide(mag_MWCNTs-ZnFC). Then, for elevating maximum adsorption capacity, more amount of zinc ferrocyanide were functionalized at surface of adsorbent (mag_MWCNTs-ZnFC-1, mag_MWCNTs-ZnFC-2, mag_MWCNTs-ZnFC-3, mag_MWCNTs-ZnFC-4, mag_MWCNTs-ZnFC-5 was composed).
The more amount of zinc ferrocyanide were used, the more maximum adsorption capacity was represented(until concentration of reagent is 0.5 M and 1.5 M, respectively K4Fe(CN)6, ZnCl2). All adsorbents have high selective removal for cesium ions (all adsorbents has maximum adsorption capacity more than 0.90 mmol/g and strong affinity to cesium ions at high concentration of sodium ions) and they are easy to recover by magnetic force (all adsorbents has magnetization more than 11.6 emu/g).
Although the mag_MWCNTs-ZnFC adsorbents were fine particles, which are difficult to use at fixed-column process, they were easily separated from wastewater after adsorption removal of cesium ion by using at high gradient magnetic fixed-column(HGM column).
Considering all of these results, the mag_MWCNTs-ZnFC adsorbents has selective and effective removal efficiency for cesium ions. All adsorbents can use as adsorption materials or reagents for decontamination for cesium ions from accident and decommissioning of nuclear power plants.

목차 (Table of Contents)

• 1. 서론 1
• 2. 이론적 배경 4
• 2.1. 방사성 폐기물의 발생 및 방사성 핵종 Cs의 특징 4
• 2.1.1. 방사성 폐기물의 발생 및 처리 4
• 2.1.2. 방사성 핵종 Cs의 특징 7
• 2.2. Cs의 흡착 분리 기술 9
• 2.2.1. CNT 지지체 기반의 흡착제 특성 11
• 2.2.2. Metal ferrocyanide를 이용한 Cs의 선택적 흡착 16
• 2.2.3. 흡착 평형 20
• 2.2.4. Column을 이용한 흡착 22
• 2.3. 흡착제의 자력 분리 25
• 2.3.1. 자성을 띤 흡착제를 이용한 Cs의 흡착 25
• 2.3.2. 입자 크기에 따른 자력 고액분리 특성 27
• 2.3.3. High Gradient Magnetic Separation 29
• 3. 흡착제 합성 및 실험방법 33
• 3.1. 실험재료 및 시약 33
• 3.2. 흡착제 합성 34
• 3.2.1. 흡착제 합성 34
• 3.2.2. 물리화학적 특성 분석 37
• 3.3. 실험방법 39
• 3.3.1. 등온 흡착 실험 39
• 3.3.2. 경쟁 흡착 실험 39
• 3.3.3. 흡착제 회수 실험 40
• 3.3.4. High Gradient Magnetic Column 흡착 실험 41
• 4. 실험결과 및 고찰 42
• 4.1. 흡착제의 물리화학적 특성 분석 42
• 4.1.1. 흡착제의 화학적 특성 42
• 4.1.2. 흡착제의 물리적 특성 48
• 4.2. 흡착제의 Cs 흡착 성능 평가(Batch Experiment) 57
• 4.2.1. Cs 흡착 성능 평가 57
• 4.2.2. 경쟁 이온 존재 시 Cs의 선택적 흡착 특성 62
• 4.2.3. 흡착제 회수 64
• 4.3. High Gradient Magnetic Column 흡착 실험 67
• 4.3.1. High Gradient Magnetic Column 수력학적 특성 67
• 4.3.2. High Gradient Magnetic Column의 Cs 흡착 특성 73
• 5. 결론 77
• 6. 참고문헌 79
• 7. 초록 86