대한환경공학회지 (Journal of Korean Society of Environmental Engineers)

  • 제29권7호
  • /
  • Pages.778-782
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  • 2007
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  • 1225-5025(pISSN)
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  • 2383-7810(eISSN)
대한환경공학회 (Korean Society of Environmental Engineers)
권호 표지

시멘트/Fe(II) 시스템에서의 TCE 분해 기작

Degradation Mechanisms of TCE in Cement/Fe(II) Systems

  • Lee, Yun-Mo (Department of Civil Engineering, Hanyang University) ;
  • Kang, Wan-Hyup (Department of Civil Engineering, Hanyang University) ;
  • Choi, Won-Ho (Department of Civil Engineering, Hanyang University) ;
  • Hwang, In-Sung (Department of Civil and Environmental engineering, Pusan National University) ;
  • Park, Joo-Yang (Department of Civil Engineering, Hanyang University)
  • 발행 : 2007.07.31
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초록

본 연구는 시멘트/Fe(II) 시스템의 TCE 분해 기작에 관한 것이다. 회분식 슬러리 실험을 통해 시멘트/Fe(II) 시스템 내에서 선별된 이온들의 거동을 조사하였다. 시멘트/Fe(II) 시스템에서 주입된 Fe(II)은 반응시간 12시간 이내에 대부분 고체상으로 흡착되었으며 Fe(II)와 함께 주입된 sulfate 역시 12시간 이내에 90% 정도 고체상으로 이동하였다. 시멘트/Fe(II) 시스템의 Fe(II)-Fe(III) (수)산화물 형성을 모사한 적철석/CaO/Fe(II) 시스템의 TCE 분해능 실험결과 시멘트/Fe(II)에 상응하는 분해속도를 보였다. 칼슘산화물은 시멘트 수화물의 주요 구성성분의 하나로서 시멘트 내에 60% 정도 함유되어 있으며 제한된 조건에서 반응성을 갖는 것으로 알려져 있다. 적철석은 시멘트에 포함되어 있는 철산화물을 모의한 것으로 선별실험을 통해 결정하였다. 적철석/CaO/Fe(II) 시스템 내에서의 Fe(II)과 sulfate의 초기 거동은 시멘트/Fe(II) 시스템과 거의 유사하게 나타났다. 적철석/CaO/Fe(II) 시스템을 이용한 TCE 분해 kinetic 실험결과와 선별된 이온들인 Fe(II)과 $SO_4^{2-}$의 초기 거동으로 볼 때 시스템 내에서 green rust와 같은 Fe(II)-Fe(III) 혼합 광물이 형성되는 것으로 판단된다. 따라서 시멘트/Fe(II) 시스템의 TCE 분해는 시멘트에 흡착된 Fe(II)이 반응성을 갖는 Fe(II)-Fe(III) (수)산화물로의 변환을 통한 기작을 갖는 것으로 판단된다.

This study investigated the dechlorination mechanisms of TCE by Fe(II) associated with cement. Batch slurry experiments were peformed to investigate the behaviors of selected ions; Fe(II), Fe(III), $Ca^{2+}$, $SO_4^{2-}$ in cement/Fe(II) system. The kinetic experiments of TCE in cement/Fe(II) systems showed that injected Fe(II) was mostly sorbed on cement within 0.5 day and 90% of injected 200 mM sulfate was sorbed on cement within 0.5 day when $[TCE]_0$ = 0.25 mM and $[Fe(II)]_0$ = 200 mM. The kinetic experiments of TCE in hematite/CaO/Fe((II) systems were conducted for simulation of cement/Fe(II) system. Calcium oxide that is one of the major components in cement hydration reactions or has a reactivity in limited conditions. Hematite assumed the ferric iron oxide component of cement. The reactivities observed in hematite/CaO/Fe(II) system were comparable to those reported for cement/Fe(II) systems containing similar molar amounts of Fe(II). The behavior of Fe(II) and $SO_4^{2-}$ sorbed on solid phase at an early stage of reaction in hematite/CaO/Fe(II) system was similar to that of cement/Fe(II) system. Ferric ion was released from hematite at an early period of reaction at low pH. The experimental evidence of kinetic test using hematite/CaO/Fe(II) system implies that the reactive reductant is a mixed-valent Fe(II)-Fe(III) mineral, which may be similar to green rust. Fe(II) sorbed on cement can be converted to new mineral phase having a reactivity such as Fe(II)-Fe(III) (hydr)oxides in cement/Fe(II) systems.

키워드

참고문헌

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