Journal of Korean Society for Atmospheric Environment (한국대기환경학회지)

Korean Society for Atmospheric Environment (한국대기환경학회)
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A Comparative Study on Degradation of BTEX Vapor by O3/UV, TiO2/UV, and O3/TiO2/UV System with Operating Conditions

운전조건에 따른 O3/UV, TiO2/UV 및 O3/TiO2/UV 시스템의 BTEX 증기처리에 관한 비교 연구

  • Kim, Kyoung-Jin (Department of Environmental Engineering, Pusan National University) ;
  • Park, Ok-Hyun (Department of Environmental Engineering, Pusan National University)
  • Published : 2008.02.29
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Abstract

A multilayer tower-type photoreactor, in which $TiO_2$-coated glass-tubes were installed, was used to measure the vapor-phase BTEX removal efficiencies by ozone oxidation ($O_3$/UV), photocatalytic oxidation ($TiO_2$/UV) and the combination of ozone and photocatalytic oxidation ($O_3/TiO_2$/UV) process, respectively. The experiments were conducted under various relative humidities, temperatures, ozone concentrations, gas flow rates and BTEX concentrations. As a result, the BTEX removal efficiency and the oxidation rate by $O_3/TiO_2$/UV system were highest, compared to $O_3$/UV and $TiO_2$/UV system. The $O_3/TiO_2$/UV system accelerated the low oxidation rate of low-concentration organic compounds and removed organic compounds to a large extent in a fixed volume of reactor in a short time. Therefore, $O_3/TiO_2$/UV system as a superimposed oxidation technology was developed to efficiently and economically treat refractory VOCs. Also, this study demonstrated feasibility of a technology to scale up a photoreactor from lab-scale to pilot-scale, which uses (i) a separated light-source chamber and a light distribution system, (ii) catalyst fixing to glass-tube media, and (iii) unit connection in series and/or parallel. The experimental results from $O_3/TiO_2$/UV system showed that (i) the highest BTEX removal efficiencies were obtained under relative humidity ranging from 50 to 55% and temperature ranging from 40 to $50^{\circ}C$, and (ii) the removal efficiencies linearly increased with ozone dosage and decreased with gas flow rate. When applying Langmuir-Hinshelwood model to $TiO_2$/UV and $O_3/TiO_2$/UV system, reaction rate constant for $O_3/TiO_2$/UV system was larger than that for $TiO_2$/UV system, however, it was found that adsorption constant for $O_3/TiO_2$/UV system was smaller than that for $TiO_2$/UV system due to competitive adsorption between organics and ozone.

Keywords

References

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