초록 ▼

연차 목표
▪ 스트론튬 선택성 고효율 흡착제 개발 (Sr 흡착능 30mg/g)
- 금속산화물계, 유기계 및 바이오(biosorbent) 흡착소재 제조
- 스트론튬 선택성 흡착제의 해수 내 물리화학적 특성 분석
- 흡착제의 해수 스트론튬 흡착 메커니즘 규명
▪ 스트론튬 흡·탈착 기술 개발 및 공정 설계
- 스트론튬 흡·탈착 공정 요소기술 개발
- 고효율 스트론튬 흡·탈착 공정 설계
개발내용 및 결과
▪ Titante-nanotube 합성 및 성능평가
[흡착능: 91.7 mg/g (

연차 목표
▪ 스트론튬 선택성 고효율 흡착제 개발 (Sr 흡착능 30mg/g)
- 금속산화물계, 유기계 및 바이오(biosorbent) 흡착소재 제조
- 스트론튬 선택성 흡착제의 해수 내 물리화학적 특성 분석
- 흡착제의 해수 스트론튬 흡착 메커니즘 규명
▪ 스트론튬 흡·탈착 기술 개발 및 공정 설계
- 스트론튬 흡·탈착 공정 요소기술 개발
- 고효율 스트론튬 흡·탈착 공정 설계
개발내용 및 결과
▪ Titante-nanotube 합성 및 성능평가
[흡착능: 91.7 mg/g (D.I.water), 0.25 mg/g (Seawater)]
▪ Alginate bead 제조 및 성능평가
[흡착능: 110 mg/g (D.I.water), 3.5 mg/g (Seawater)]
▪ MnO₂/CNT복합체 제조 및 성능평가
[흡착능: 30 mg/g (D.I.water), 2.57 mg/g (Seawater)]
▪ MnO₂/Fe₃O₄ 복합체 제조 및 성능평가
[흡착능: 42.2 mg/g (D.I.water), 1.4 mg/g (Seawater)]
▪ Zeolite계열 소재의 흡착제 적용연구 - 천연/합성 제올라이트 Sr 흡착능 평가
[천연제올라이트: 23.6mg/g (D.I.water),합성제올라이트: 101.2mg/g (D.I.water)]
▪ 컬럼형(70.5cm³) 연속식 회수공정 개발
[alginate-bead 적용, 해수 Sr 회수공정]
▪ 해수 Sr 탈착시스템 및 농축공정 개발
[해수 Sr 농축액 농도: 63 mg/L]
기대효과
▪ 스트론튬의 새로운 수급체계 확보에 따른 관련 산업의 안정적 발전에 기여
▪ 스트론튬 회수 원천기술을 확보, 향후 성장 가능한 미래소재시장 선점
▪ 새로운 산업의 육성으로 인력 고용 효과 유발
▪ 다양한 해수용존 유용자원 회수기술개발을 위한 기반기술 활용
적용분야
▪ 해수 추출 스트론튬의 국내산업 활용
▪ 개발된 스트론튬 회수 기술(흡착/회수 공정모델)을 다양한 해수용존 유용금속 회수공정에 확대응용
▪ 방사성 스트론튬 제거 및 회수공정에 확대응용

Abstract ▼

Strontium (Sr) which has many industrial applications such as ferrite magnet, ceramic, and fire works exists in seawater with the concentration of approximately 7 mg/L. In previous report estimating economic potential on recovery of various elements from seawater in terms of their commercial values

Strontium (Sr) which has many industrial applications such as ferrite magnet, ceramic, and fire works exists in seawater with the concentration of approximately 7 mg/L. In previous report estimating economic potential on recovery of various elements from seawater in terms of their commercial values and concentrations in seawater, Sr locates upper than approximate break-even line, which implies Sr recovery from seawater can be potentially profitable. Recently, Sr separation from seawater has received great attention in the environmental aspect after Fukushima Nuclear Power Plant (NPP) accident which released much amount of radioactive Sr and Cs. Accordingly, the efficient separation of radioactive elements released to seawater has become critical as an important technological need as well as their removal from radioactive wastes.
So far, it has been introduced to separate Sr from aqueous media by various methods including solvent extraction, adsorption by solid materials, and ion exchange. Among them, the adsorption technique using solid adsorbents is of great interest for selectively separating Sr from seawater with respect to low concentration level of Sr. Herein, we report Sr recovery from seawater using various kinds of adsorbents.
Zeolites have been known as an excellent adsorbent for its high ion exchange capacity, selectivity, and environmentally friendly materials, which are microporous crystalline aluminosilicatese. Among zeolites, Na-A zeolite has excellent adsorption properties for strontium ion (Sr²⁺), in which the selectivity for ions is in the order of Cs⁺ > Rb⁺ > K⁺ > NH₄ ⁺ > Sr²⁺ > Na⁺ > Ca²⁺ > Fe²⁺ > Al³⁺ > Mg²⁺ > Li+. In this work, the adsorption properties of Na-A zeolite was investigated by using Sr containing solution with competition test for co-existing ions, which shows good adsorption performance.
Alginate bead was investigated as low-cost strontium bio-sorbent. Alginate bead has demonstrated a superior adsorption capacity for Sr ions (110 mg/g). The mechanism of Sr adsorption was inferred as an ion exchange reaction with Ca ion. It could be regenerated by using 0.5M CaCl₂ solution without damage on adsorbent and Sr adsorption capacity did not decrease after three repeated uses. Despite negative effect of concentrated ions in seawater, alginate bead showed 3.5 mg/g of Sr adsorption capacity in seawater.
Titanate nanostructures have been attracting too much interest in most of research fields due to its special physicochemical properties as effective nano-structure, specific surface area and easy as well as economical one step synthesis process. Unique physicochemical properties make titanate nanotubes (TNTs) as wide acceptable nanomaterial in different applications such as in Li-ion batteries, photo-catalysis, hydrogen storage, solar batteries, ion-exchange and gas sensors. Additionally, the titanate nanotubes can be used as excellent adsorbents for the removal as well as recovery applications of both organic and inorganic materials such as hazardous metals ions (e.g. Pb²⁺ and Cd²⁺), heavy metal cations (e.g. Ni²⁺, Cr²⁺, Cu²⁺ and Sr²⁺), dyes and radioactive isotopes due to their high surface area (abundant hydroxyl groups) and ion exchange capability. In this study, strontium uptake has demonstrated by titanate nanotubes. The titanate nanotubes with high specific surface area have allowed more strontium ions from aqueous solution by ion-exchange mechanism.
Carbon-hydrous manganese oxide composite (h-MnO₂/MWCNT) and nano-structured MnO₂ were synthesized and characterized as inorganic ion exchange for the sorption recovery of strontium (Sr) from seawater. These h-MnO₂ adsorbents represented a high selectivity for Sr adsorption, and Ca and Mg ions significantly hindered the Sr adsorption in seawater. Nano-structure MnO₂ materials demonstrated the dependence of Sr selectivity on the crystallographic forms. That is, the δ-phase showed a higher Sr selectivity than α-phase. The ball-type adsorption module including adsorbent performed effectively the whole recovery process (adsorption-desorption-concentration) without any loss in the performance of adsorbent.
In practical point of view related to Sr recovery from seawater, continuous Sr adsorption column system was developed and applied to recovery of real seawater Sr. Alginate bead was packed in the column module and used as Sr adsorbent. Continuous seawater Sr recovery column system was operated by following procedure; 1) Sr adsorption (seawater) 2) washing (D.I.water) 3) desorption/concentration (0.1 M HCl, circulation). All the solution was supplied by peristaltic pump in upflow mode. Seawater Sr adsorption equilibrium was obtained at 9 hours with 50~100 ml/min flow rate. After washing the column module with D.I. water, 0.1 M HCl was injected to column as eluent to desorb Sr from column module. Finally 65 mg/L seawater Sr was recovered in eluent after 15 times repeated elution of column modules. It was 10-folds higher Sr concentration compared with seawater.

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 연차보고서 요약서 ... 4
• 요약문 ... 6
• SUMMARY ... 8
• CONTENTS ... 10
• 목차 ... 12
• 제1장 연구개발과제의 개요 ... 16
• 제1절 연구개발의 목적 및 필요성 ... 16
• 1. 기술개발 목적 및 필요성 ... 16
• 2. 기술개발 개요 ... 17
• 제2절 연구개발 범위 ... 17
• 1. 최종목표 ... 17
• 2. 당해 연도 연구개발내용 ... 18
• 제2장 국내외 기술개발 현황 ... 19
• 제1절 국내의 경우 ... 19
• 1. 국·내외적으로 해수로부터 스트론튬회수공정개발기술은 거의 전무한 실정 ... 19
• 2. 도시 광산 산업시도 ... 19
• 3. 환경 친화적인 청정 스트론튬 회수공정개발의 필요성 ... 19
• 4. 삼면이 바다인 우리나라의 해양자원을 기반으로 하여 스트론튬 회수연구 필요 ... 19
• 5. 국내연구자들에 의한 스트론튬회수연구 ... 19
• 제2절 국외의 경우 ... 19
• 1. 해수로부터 희유금속확보를 위한 기술개발 ... 19
• 2. 미국의 희유금속 확보책 ... 19
• 3. EU의 희유금속 확보책 ... 20
• 4. 일본의 희유금속 확보책 ... 20
• 5. 중국의 희유금속 확보책 ... 20
• 6. 스트론튬의 Bio-sorption ... 20
• 제3절 기술개발 현황 ... 20
• 1. 전이금속-Sr 복합 흡착제를 이용한 회수공정개발 ... 20
• 2. 제올라이트 기반의 이온교환 흡착제 개발 ... 20
• 3. 천연 열대과일껍질을 활용한 흡착제 개발 ... 21
• 제3장 연구개발수행 내용 및 결과 ... 22
• 제1절 제올라이트(Zeolite) 계열 흡착소재 ... 22
• 1. Na-A 제올라이트 흡착제 ... 22
• 제2절 알긴산염(Alginate) 기반 바이오 흡착소재 ... 26
• 1. Alginate bead 흡착제 ... 26
• 제3절 티탄산염(Titanate) 계열 이온 교환체 ... 36
• 1. 해수로부터 Sr 분리를 위한 Na-Titanate 적용 : Ca이온이 Sr 흡착거동에 미치는 영향 ... 36
• 2. TiO2 및 금속이 도핑된 TiO2 나노와이어 합성과 나노와이어를 이용한 타이타네이트 나노튜브합성 최적화 ... 48
• 3. Carbon 소재를 이용한 Titanate Nanotube 복합소재 합성 ... 57
• 4. 망간산화물/Titanate Nanotube 복합소재 합성 ... 64
• 제4절 고성능 함수 망간산화물(Hydrous MnO2) 흡착소재 ... 67
• 1. 함수 망간산화물/카본 복합소재 ... 67
• 2. 함수 망간산화물 나노구조 소재 ... 70
• 제5절 기공조절 가능 3차원 다공성 구조체 ... 74
• 1. 비정질 다공성 실리카 합성 및 특성 분석 ... 74
• 2. 비정질 실리카 스트론튬 흡착 실험 ... 78
• 3. graphitic carbon nitride/silica 복합체 합성 ... 78
• 4. Encapsulated g-CN on alginate-based bead ... 81
• 제6절 해수용존 스트론튬 회수공정 요소기술 ... 97
• 1. 해수 내 용존 자원 회수 시스템 개발 ... 97
• 2. 컬럼형(Column type) 연속식 해수 스트론튬 회수공정 설계 ... 99
• 3. 컬럼형 연속식 해수 스트론튬 흡/탈착 조건 도출 연구 ... 101
• 4. 컬럼형 연속식 해수 스트론튬 농축 연구 ... 104
• 제4장 목표달성도 및 관련분야에의 기여도 ... 107
• 제5장 연구개발결과의 활용계획 ... 108
• 제6장 참고문헌 ... 109
• 끝페이지 ... 111