• Title/Summary/Keyword: photocatalysis

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Photocatalysis of Low Concentration of Gaseous-Phase Benzene Using Visible-Light Irradiated N-doped and S-doped Titanium Dioxide

  • Jo, Wan-Kuen;Kim, Jong-Tae
    • Environmental Engineering Research
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    • v.13 no.4
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    • pp.171-176
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    • 2008

  • Studies on visible-light-driven photocatalysis of air pollutants at indoor air quality (IAQ) levels have been limited. Current study investigated visible-light derived photocatalysis with N-doped and S-doped titanium dioxide ($TiO_2$) for the control of benzene at indoor levels. Two preparation processes were employed for each of the two types of photocatalyst: urea-Degussa P-25 $TiO_2$ and titania-colloid methods for the N-doped $TiO_2$; and titanium isopropoxid- and tetraisopropoxide-thiourea methods for the S-doped $TiO_2$. Furthermore, two coating methods (EDTA- and acetylacetone-dissolving methods) were tested for both the N-doped and S-doped $TiO_2$. The two coating methods exhibited different photocatalytic degradation efficiency for the N-doped photocatalysts, whereas they did not exhibit any difference for the S-doped photocatalysts. In addition, the two doping processes showed different photocatalytic degradation efficiency for both the S-doped and N-doped photocatalysts. For both the N-doped and S-doped $TiO_2$, the photocatalytic oxidation (PCO) efficiency increased as the hydraulic diameter (HD) decreased. The degradation efficiency determined via a PCO system with visible-light induced $TiO_2$ was lower than that with UV-light induced unmodified $TiO_2$, which was obtained from previous studies. Nevertheless, it is noteworthy that for the photocatalytic annular reactor with the HD of 0.5 cm, PCO efficiency increased up to 52% for the N-doped $TiO_2$ and 60% for the S-doped $TiO_2$. Consequently, when combined with the advantage of visible light use over UV light use, it is suggested that with appropriate HD conditions, the visible-light-assisted photocatalytic systems can also become an important tool for improving IAQ.

  • https://doi.org/10.4491/eer.2008.13.4.171 인용 PDF KSCI

Use of a Combined Photocatalysis/Microfiltration System for Natural Organic Matter Removal (광촉매 반응과 침지형 정밀여과를 이용한 자연산 유기물의 제거)

  • 추광호;박경원;김문현
    • Membrane Journal
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    • v.14 no.2
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    • pp.149-156
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    • 2004

  • This work focused on the degradation of natural organic matter (NOM) present in lake water using a combined pkotocatalysisimicrofiltration (MF) process. The system performances were investigated in terms of organic removal efficiency and membrane permeability. The addition of iron oxide particles (IOP) into the photocatalytic membrane reactor improved initial NOM removal by sorption, but during photocatalysis the removal efficiency was reversed, probably due to the scattering of UV light by IOP. The modification of TiO$_2$ surfaces by IOP deposition was conducted to enhance the photocatalytic NOM removal efficiency. A minimal amount of Impregnation of IOP on TiO$_2$ surfaces was required to prevent the light scattering effect as well. The coating of MF membranes with IOP helped to improve the NOM removal efficiency while sorbing NOM by IOP. Regardless of tile operating conditions and particles addition examined, no significant fouling was occurring at a flux of 15 L/$m^2$-h during entire MF operation.

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