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생지화학적 환원조건에서 우라늄의 침철석 및 몬모릴로나이트에 대한 수착 특성

Sorption Characteristics of Uranium on Goethite and Montmorillonite under Biogeochemical Reducing Conditions

  • 이승엽 (한국원자력연구원 방사성폐기물처분연구부 및 원자력화학연구부) ;
  • 조혜륜 (한국원자력연구원 방사성폐기물처분연구부 및 원자력화학연구부) ;
  • 백민훈 (한국원자력연구원 방사성폐기물처분연구부 및 원자력화학연구부) ;
  • 정의창 (한국원자력연구원 방사성폐기물처분연구부 및 원자력화학연구부) ;
  • 정종태 (한국원자력연구원 방사성폐기물처분연구부 및 원자력화학연구부)
  • 투고 : 2012.12.14
  • 심사 : 2012.12.26
  • 발행 : 2012.12.31

초록

산화/환원 반응에 매우 민감한 우라늄의 침철석 및 몬모릴로나이트에 대한 수착 특성을 알아보기 위해 산화우라늄(VI)과 환원우라늄(IV)를 준비하였다. 환원우라늄은 황산염환원박테리아에 의해 황산염이 환원되는 과정에서 같이 환원된 우라늄(IV)를 희석하여 사용하였다. 광물에 대한 우라늄의 수착량은 우라늄(IV)가 우라늄(VI)에 비해 상대적으로 낮았으며, 이러한 원인 중의 하나는 용액상의 우라늄(IV)가 미세한 콜로이드 형태로 존재하여 광물 표면에 대한 수착력이 약했기 때문이다. 투과전자현미경을 사용하여 우라늄(IV)가 나노 콜로이드의 특징을 가지고 있음을 확인하였고, 이러한 결과는 심부 자연계의 지하수를 따라 이동 가능한 우라늄종이 이온성 우라늄(VI)뿐만 아니라 콜로이드성 우라늄(IV)도 포함될 수 있음을 의미한다.

Two kinds of uranium species, oxidized uranium(VI) and reduced uranium(IV), were prepared to be interacted with goethite and montmorillonite to identify sorption characteristic of uranium species, which are very sensitive to the redox-reaction. The reduced uranium was prepared by diluting a substantial uranium(IV) that was concomitantly produced during a sulfate reduction via a sulfate-reducing bacterium. The sorption amount of uranium(IV) by the minerals was relatively lower than that of uranium(VI) because the aqueous uranium(IV) had fine colloidal forms to cause its weak adsorption onto the mineral surfaces. We found that the uranium(IV) phase has a nano-colloid character by the transmission electron microscope, suggesting that the uranium species possibly migrating with the flow of groundwater in underground environments can be the colloidal uranium(IV) as well as the ionic uranium(VI).

키워드

참고문헌

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