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Optimization of Electrolytic Oxidant OCl- Production for Malodorous VOCs Removal

악취성 VOCs 제거를 위한 전해 산화제 OCl-의 생산 최적화

  • Yang, Woo Young (Department of Chemical Engineering, Soongsil University) ;
  • Lee, Tae Ho (Department of Chemical Engineering, Soongsil University) ;
  • Ryu, Hee Wook (Department of Chemical Engineering, Soongsil University)
  • 양우영 (숭실대학교 화학공학과) ;
  • 이태호 (숭실대학교 화학공학과) ;
  • 류희욱 (숭실대학교 화학공학과)
  • Received : 2021.03.19
  • Accepted : 2021.05.26
  • Published : 2021.06.30

Abstract

Volatile organic compounds (VOCs) occur in indoor and outdoor industrial and urban areas and cause environmental problems. Malodorous VOCs, along with aesthetic discomfort, can have a serious effect on the human body. Compared with the existing method of reducing malodorous VOCs, a wet scrubbing method using an electrolytic oxidant has the advantage of reducing pollutants and regenerating oxidants. This study investigated the optimal conditions for producing OCl-, a chlorine-oxidant. Experiments were conducted by changing the type of anode and cathode electrode, the type of electrolyte, the concentration of electrolytes, and the current density. With Ti/IrO2 as the anode electrode and Ti as the cathode electrode, OClproduction was highest and most stable. Although OCl- production was similar with the use of KCl or NaCl, NaCl is preferable because it is cheap and easy to obtain. The effect of NaCl concentration and current density was examined, and the OCl- production rate and concentration were highest at 0.75 M NaCl and 0.03 A cm-2. However, considering the cost of electric power, OCl- production under the conditions of 1.00 M NaCl and 0.01 A cm-2 was most effective among the conditions examined. It is desirable to produce OCl- by adjusting the current density in accordance with the concentration and characteristics of pollutants.

다양한 환경문제를 일으키는 휘발성 유기 화합물(volatile organic compounds, VOCs)은 산업 지대 및 도심의 실내외에서 다양하게 발생한다. 악취성 VOCs는 심미적 불쾌함과 더불어 인체에 심각한 영향을 미칠 수도 있다. 기존에 악취성 VOCs를 저감하는 방식에 비하여, 전기 분해를 통해 생산된 산화제를 이용한 수세정 방식은 오염 물질 저감과 동시에 산화제의 재생이 가능하다는 장점이 있다. 본 연구에서는 염소계 산화제인 OCl-을 생산하기 위한 최적 조건을 연구하였다. 산화 및 환원 전극의 종류와 전해질의 종류, 전해질의 농도 및 전류 밀도를 변화시켰다. 산화 전극은 Ti/IrO2, 환원 전극은 Ti을 사용하였을 때 OCl- 생산이 가장 우수하고 안정적이었다. 전해질의 OCl- 생산 능력은 KCl과 NaCl이 유사하게 나타났으나, 경제적이고 쉽게 구할 수 있는 NaCl이 최적이라고 판단하였다. OCl- 생산 속도가 우수하고 농도가 가장 높게 생산된 NaCl 농도 및 전류 밀도 조건은 0.75 M NaCl, 0.03 A cm-2이었다. 하지만 전력 비용을 고려했을 때 본 실험에서는 1.00 M NaCl, 0.01 A cm-2의 조건의 OCl- 생산이 가장 효율적이었다. 실제 현장 적용시 오염물질의 농도 및 특성에 따라서 전류밀도를 조절하여 OCl-을 생산하는 것이 바람직할 것이다.

Keywords

Acknowledgement

본 결과물은 환경부의 재원으로 한국환경산업기술원의 환경정책기반 공공기술 개발 사업의 지원을 받아 연구되었습니다(2017000700002).

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