Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Prediction of Adsorption Isotherms and Diffusivity on Activated Carbon for Persistent Organic Pollutant(2,3,7,8-TCDD)

활성탄 위에서 잔류성 유기 오염물질(2,3,7,8-TCDD)의 등온 흡착식 및 확산계수 예측

  • Lim, Young-Il (Lab. FACS, RCCT, Department of Chemical Engineering, Hankyong National University) ;
  • Son, Hae-Jeong (Lab. FACS, RCCT, Department of Chemical Engineering, Hankyong National University) ;
  • Lee, Ohsung (Lab. FACS, RCCT, Department of Chemical Engineering, Hankyong National University) ;
  • Nam, Kyong-Soo (Department of Environment Engineering, Kwangwoon University) ;
  • Yoo, Kyoung-Seun (Department of Environment Engineering, Kwangwoon University)
  • 임영일 (한경대학교 화학공학과 FACS 연구실) ;
  • 손혜정 (한경대학교 화학공학과 FACS 연구실) ;
  • 이오성 (한경대학교 화학공학과 FACS 연구실) ;
  • 남경수 (광운대학교 환경공학과) ;
  • 유경선 (광운대학교 환경공학과)
  • Received : 2009.08.12
  • Accepted : 2009.09.18
  • Published : 2009.12.31
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Abstract

In this study, adsorption isotherms of o-DCB(ortho-dichlorobenzene) on an activated carbon heated at $1000^{\circ}C$ for 24 hours were obtained by experiment and were predicted by using molecular simulation. The initial molecular structure of the activated carbon was designed on the basis of its molecular formula and functional groups ratio measured experimentally. Then, the molecular structure was optimized using the COMPASS(condensed-phase optimized molecular potentials for atomistic simulation studies) force field. The particle porosity, specific surface area, and particle density obtained from the optimized molecular structure of activated carbon were compared with those experimental data. The errors between experimental data and simulation results of the particle porosity, specific surface area, and particle density were shown as 7.6, 3.8, and 2.8%, respectively. Adsorption isotherms constants of o-DCB are calculated by the GCMC(grand canonical Monte Carlo) method in the optimized molecular structure of activated carbon. The simulation result of the adsorption isotherms showed an error of under 3%, compared to that of experimental data. Adsorption isotherms, adsorption heat and pore diffusivity of 2,3,7,8-TCDD(tetrachlorodibenzo-p-dioxin) was finally obtained in the same molecular structure of the activated carbon as used for o-DCB. Thus, adsorption characteristics of persistent organic pollutants on activated carbon, which are not easy to experimentally evaluate, are predicted by the molecular simulation.

본 연구에서는 $1,000^{\circ}C$에서 24시간 열처리된 활성탄에서 다이옥신과 유사구조를 갖는 o-DCB(ortho-dichlorobenzene)의 등온흡착식을 실험을 통하여 구하였고, 분자모사를 통하여 예측하였다. 실험으로 분석된 활성탄의 분자식 및 작용기 비율을 바탕으로 초기 활성탄 기본구조를 설계한 후, COMPASS(condensed-phase optimized molecular potentials for atomistic simulation studies) force field를 이용하여 이 구조를 최적화하였다. 최적화된 활성탄 분자구조에서 공극률, 비표면적, 및 입자밀도의 모사결과는 실험값과 비교되었고, 이들에 대한 실험과 모사결과의 오차는 각각 7.62, 3.79, 2.80%를 보여주었다. 통계 열역학적 방법인 GCMC(Grand Canonical Monte Carlo) 기법을 이용하여, 최적화된 활성탄 구조에서 온도에 따른 o-DCB의 등온흡착 상수값을 예측하였으며, 이 모사결과는 실험값과 비교될 때, 3% 이하의 오차를 보였다. o-DCB의 흡착특성을 바탕으로 확인되어진 활성탄 구조에서 다이옥신의 일종인 2,3,7,8-TCDD(tetrachlorodibenzo-p-dioxin) 등온흡착상수, 흡착열, 그리고 기공확산계수를 최종적으로 구함으로서, 실험적으로 구하기 힘든 맹독성 잔류성 유기물질의 흡착특성을 분자모사기법을 통하여 예측하였다.

Keywords

Acknowledgement

Supported by : Hankyong National University

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