Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Photocatalytic disinfection of indoor suspended microorganisms (Escherichia coli and Bacillus subtilis spore) with ultraviolet light

광촉매와 UVA에 의한 실내 부유 미생물(E. coli 및 Bacillus. subtilis sp.) 살균 제거 연구

  • Yoon, Young H. (Environmental Engineering Research Division, Korea Institute of Construction & Technology) ;
  • Nam, Sook-Hyun (Environmental Engineering Research Division, Korea Institute of Construction & Technology) ;
  • Joo, Jin-Chul (Environmental Engineering Research Division, Korea Institute of Construction & Technology) ;
  • Ahn, Ho-Sang (Environmental Engineering Research Division, Korea Institute of Construction & Technology)
  • 윤영한 (한국건설기술연구원 수자원환경연구본부 환경연구실) ;
  • 남숙현 (한국건설기술연구원 수자원환경연구본부 환경연구실) ;
  • 주진철 (한국건설기술연구원 수자원환경연구본부 환경연구실) ;
  • 안호상 (한국건설기술연구원 수자원환경연구본부 환경연구실)
  • Received : 2013.10.23
  • Accepted : 2014.02.05
  • Published : 2014.02.28
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Abstract

New control methods are proposed for indoor air quality by removing fine airborne dust-particles. As suspended fine dust-particles contain inorganic dust as well as fine organic bacteria, studies for simultaneous control of these contaminants are required. In this study, photocatalytic disinfection of indoor suspended microorganisms such as E. coli and Bacillus subtilis is performed by three types of photocatalysts with UVA irradiation. The UVA irradiation strength was controlled to the minimum $3{\mu}W/cm^2$, and ZnO, $TiO_2$, and ZnO/Laponite ball were used as the catalysts. The results indicate that E. coli was removed over 80 % after about 2 hours of reaction with UVA and all three types of photocatalysts, whereas only with UVA, around 50 % E. coli removal was obtained. Among the catalysts, ZnO/Laponite composite ball was found to have similar sterilizing capacity to $TiO_2$. However, in case of B. subtilis, which has thick cell wall in its spore state, disinfection was not effective under the low UVA irradiation condition, even with the catalysts. Further studies need to figure out the optimal UVA irradiation ranges as well as photocatalysts doses to control airborne dust, to provide healthy clean air environment.

실내공기 오염물질의 제어를 통하여 공기질을 개선시킬 수 있는 요소기술의 개발을 위하여 미세부유먼지 제거방법을 도출하고자 하였다. 미세부유먼지 중에는 분진과 같은 무기물과 박테리아와 같은 작은 유기물도 포함되어 있어 이들의 동시 제거를 위한 연구가 필요하다. 본 연구에서는 광촉매 및 UVA에 의한 미세부유먼지 중 미생물 제거 기술의 개발을 위하여 여러 종류의 광촉매에 대한 미생물 살균율을 조사하였다. 이를 위하여 3가지 종류의 광촉매(ZnO, $TiO_2$, ZnO/Laponite ball)와 최소한의 UVA 자외선 조사량 3 (${\mu}W/cm^2$)을 이용하여 실내공기 부유미생물의 지표로 사용되는 Gram 양성균인 E. Coli와 Gram 음성균인 Bacillus. subtilis sp.에 대하여 살균실험을 진행하였다. 실험결과, 최소한의 UVA 자외선 조사량에서도 광촉매제와 함께 두 시간 정도 반응하였을 때 E-Coli의 경우 세 가지 광촉매제 모두에서 80 % 이상 사멸되는 것으로 나타났으며, UVA 단독 사용보다는 약 30 % 높은 사멸률을 보였다. 광촉매제 중에는 ZnO/Laponite ball 복합체의 경우에 $TiO_2$와 동등한 살균력이 있는 것으로 나타났다. 하지만, 포자상태에서 강한 외벽을 가지고 있는 B. subtilis sp.의 경우는 낮은 자외선 조사량으로는 살균효과가 저하되기 때문에 살균율을 높일 수 있는 최적의 촉매제 종류와 첨가량 및 자외선 조사량을 찾아야 할 것으로 판단된다.

Keywords

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