Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Evaluation of Denitrification Reactivity by the Supported Nanoscale Zero-Valent Iron Prepared in Ethanol-Water Solution

이중용매에서 제조된 나노영가철을 이용한 질산성질소의 환원반응성 평가

  • Park, Heesu (Center for Environmental Technology Research, Korea Institute of Science and Technology) ;
  • Park, Yong-Min (Center for Environmental Technology Research, Korea Institute of Science and Technology) ;
  • Oh, Soo-Kyeong (Center for Environmental Technology Research, Korea Institute of Science and Technology) ;
  • Lee, Seong-Jae (Geoworks, Research Institute for Energy and Resources) ;
  • Choi, Yong-Su (Center for Environmental Technology Research, Korea Institute of Science and Technology) ;
  • Lee, Sang-Hyup (Center for Environmental Technology Research, Korea Institute of Science and Technology)
  • 박희수 (한국과학기술연구원 환경기술연구단) ;
  • 박용민 (한국과학기술연구원 환경기술연구단) ;
  • 오수경 (한국과학기술연구원 환경기술연구단) ;
  • 이성재 (주식회사 지오웍스) ;
  • 최용수 (한국과학기술연구원 환경기술연구단) ;
  • 이상협 (한국과학기술연구원 환경기술연구단)
  • Received : 2008.06.05
  • Accepted : 2008.07.23
  • Published : 2008.10.31
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Abstract

Nanoscale zero-valent iron(nZVI) is famous for its high reactivity originated from its high surface area and it has received considerable attentions as one of the latest innovative technologies for treating contaminated groundwater. Due to its fine powdery form, nZVI has limited filed applications. The efforts to overcome this shortcoming by immobilizing nZVI on a supporting material have been made. This study investigated the differences of resin-supported nZVI's characteristics by changing the preparation methods and evaluated its reactivity. The borohydride reduction of an iron salt was proceeded in ethanol/water solvent containing a dispersant and the synthesis was conducted in the presence of ion-exchange resin. The resulting material was compared to that prepared in a conventional way of using de-ionized water by measuring the phyrical and chemical characteristics. BET surface area and Fe content of nZVI-attached resin was increased from $31.63m^2/g$ and 18.19 mg Fe/g to $38.10m^2/g$ and 22.44 mg Fe/g, respectively, by switching the solution medium from water to ethanol/water with a dispersant. The reactivity of each material was tested using nitrate solution without pH control. The pseudo first-order constant of $0.462h^{-1}$ suggested the reactivity of resin-supported nZVI prepared in ethanol/water was increased 61 % compared to that of the conventional type of supported nZVI. The specific reaction rate constant based on surface area was also increased. The results suggest that this new supported nZVI can be used successfully in on-site remediation for contaminated groundwater.

오염 지하수 처리를 위한 획기적인 방법으로 높은 반응성을 가진 나노영가철이 최근 주목을 받고 있다. 그러나 미세한 분말형태로 인하여 현장공법에 적용이 제한되어 나노영가철을 입자형태의 지지체에 부착시켜서 투수성을 유지하여 실용성을 높인 방법이 제시되었다. 본 연구에서는 지지체의 존재 하에 생성된 나노영가철이 제조방법에 따라 어떤 특성의 변화를 보이는지 분석하고 이에 따른 반응성의 차이를 평가하였다. 지지체로는 이온교환수지를 선택하였으며 분산제를 포함한 에탄올/물의 이중용매를 사용하여 나노영가철을 제조한 후 그것의 물리적, 화학적 특성 및 반응성을 기존의 물만을 사용하여 제조한 경우와 비교하였다. 이중용매 상에서 제조된 반응물질은 비표면적이 $38.10m^2/g$, 철함량이 22.4 mg Fe/g 으로 수용액상에서 제조된 반응물질 보다 비표면적과 철 함량이 각각 20%와 23% 증가하였으며 질산성질소를 이용한 반응성 평가에서도 $0.462h^{-1}$의 반응상수값을 보이며 61% 증가한 반응성을 나타냈다. 단위표면의 반응상수 또한 증가하여 단위 면적에서의 반응성도 향상된 나노영가철을 얻을 수 있었다. 제조된 반응물질은 높은 반응성과 지지체의 사용으로 실제 오염 지하수 등의 처리에서 유용하게 사용될 수 있을 것으로 기대되어진다.

Keywords

Acknowledgement

Supported by : 한국학술진흥재단

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