Photodegradation of Dye Pollutants Catalyzed by Porous K3PW12O40 under Visible Irradiation
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- 作者：Chuncheng Chen ; Qi Wang ; Pengxiang Lei ; Wenjing Song ; Wanhong Ma ; and Jincai Zhao
- 刊名：Environmental Science & Technology
- 出版年：2006
- 出版时间：June 15, 2006
- 年：2006
- 卷：40
- 期：12
- 页码：3965 - 3970
- 全文大小：318K
- 年卷期：v.40,no.12(June 15, 2006)
- ISSN：1520-5851
文摘
Microporous solid K3PW12O40 is prepared by precipitationof phosphotungstic acid and potassium ion, followed bycalcination. Using this material as photocatalyst, a seriesof dye pollutants, such as rhodamine B, malachitegreen, rhodamine 6G, fuchsin basic, and methyl violet,were efficiently degraded in the presence of H2O2 undervisible light irradiation (
> 420 nm). The photocatalyst wascharacterized via SEM, BET surface area, FT-IR, andXRD. The photocatalyst has relative large surface area,and the Keggin structure of phosphotungstic ions is intactduring the precipitation and calcination. The degradationkinetics, TOC changes, degradation products, ESR detectionof active oxygen species, and the effect of radicalscavengers are also investigated to clarify the degradationprocess and the reaction pathway. The dyes can befacilely bleached and mineralized (ca. 40% of TOC removalfor RhB), and the main degradation products of RhBdetected, besides CO2, are the small organic acids. Theyare released from the surface of the catalyst to the bulksolution during the degradation of the dye, which avoidsthe poisoning of photocatalyst by the intermediates.The formation of active oxygen species such as the O2-
/HO2 and OH are detected during the degradation ofdye, and they are proposed to be responsible for thedegradation of dyes. The K3PW12O40 catalyst is very stableand very easily separated from the reaction system forreuse.
> 420 nm). The photocatalyst wascharacterized via SEM, BET surface area, FT-IR, andXRD. The photocatalyst has relative large surface area,and the Keggin structure of phosphotungstic ions is intactduring the precipitation and calcination. The degradationkinetics, TOC changes, degradation products, ESR detectionof active oxygen species, and the effect of radicalscavengers are also investigated to clarify the degradationprocess and the reaction pathway. The dyes can befacilely bleached and mineralized (ca. 40% of TOC removalfor RhB), and the main degradation products of RhBdetected, besides CO2, are the small organic acids. Theyare released from the surface of the catalyst to the bulksolution during the degradation of the dye, which avoidsthe poisoning of photocatalyst by the intermediates.The formation of active oxygen species such as the O2-/HO2 and OH are detected during the degradation ofdye, and they are proposed to be responsible for thedegradation of dyes. The K3PW12O40 catalyst is very stableand very easily separated from the reaction system forreuse.