Inhibition effect of SO₂ on NO_x and VOCs during the photodegradation of synchronous indoor air pollutants at parts per billion (ppb) level by TiO₂

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• 作者：Ao ; C.H. ; Lee ; S.C. ; Zou ; S.C. ; Mak ; C.L.
• 关键词：Titanium dioxide ; BTEX ; Photocatalyst ; Trace level
• 刊名：Applied Catalysis B ; Environmental
• 出版年：2004
• 期刊代码：4_09263373
• 类别：ce
• 出版时间：May 28, 2004
• 卷：49
• 期：3
• 页码：187-193
• 文件大小：149 K

摘要

Sulfur-containing compounds are well-known catalyst poisons. To evaluate the feasibility of photocatalytic technology for indoor air purification, a typical atmospheric SO₂ concentration of 200 parts per billion (ppb) was selected. In order to further evaluate the impact of SO₂ on the photocatalytic activity of other typical indoor air pollutants, SO₂ was co-injected with 200ppb NO and 20ppb benzene, toluene, ethylbenzene, and o-xylene (BTEX) using TiO₂ (P-25) as photocatalyst coated on a glass fiber filter. A concurrent photodegradation of SO₂ with NO, SO₂ with BTEX, and SO₂ with NO and BTEX was also conducted. Results showed that no photodegradation of SO₂ was found. However, the blank glass fiber filter adsorbed more than 75%of the SO₂. The conversion of NO decreased by 8%and the generation of NO₂ increased by 10%with the presence of SO₂. A similar inhibition effect was found on the photodegradation of BTEX with the presence of SO₂. The presence of SO₂ decreased the conversion of BTEX by more than 10%. Ion chromatography analysis on the TiO₂ glass fiber filter showed that sulfate ion was formed from the adsorption of SO₂. The formation of sulfate ion inhibited the formation of nitrate ion, which increased the generation of NO₂. It is suggested that the inhibition effect of SO₂ is due to the sulfate ion competing with the pollutant for adsorption sites on TiO₂. The promotion effect of NO on BTEX was also reduced by the presence of SO₂.