Removal of formaldehyde over Mn(x)Ce(1)-(x)O(2) catalysts: thermal catalytic oxidation versus ozone catalytic oxidation

Autor: Sheng Jen Yu, Moo Been Chang, Shaw Yi Yan, Kuan Lun Pan, Jia Wei Li
Rok vydání: 2014
Předmět:
Zdroj: Journal of environmental sciences (China). 26(12)
ISSN: 1001-0742
Popis: Mn x Ce 1 − x O 2 (x: 0.3–0.9) prepared by Pechini method was used as a catalyst for the thermal catalytic oxidation of formaldehyde (HCHO). At x = 0.3 and 0.5, most of the manganese was incorporated in the fluorite structure of CeO 2 to form a solid solution. The catalytic activity was best at x = 0.5, at which the temperature of 100% removal rate is the lowest (270°C). The temperature for 100% removal of HCHO oxidation is reduced by approximately 40°C by loading 5 wt.% CuO x into Mn 0.5 Ce 0.5 O 2 . With ozone catalytic oxidation, HCHO (61 ppm) in gas stream was completely oxidized by adding 506 ppm O 3 over Mn 0.5 Ce 0.5 O 2 catalyst with a GHSV (gas hourly space velocity) of 10,000 hr − 1 at 25°C. The effect of the molar ratio of O 3 to HCHO was also investigated. As O 3 /HCHO ratio was increased from 3 to 8, the removal efficiency of HCHO was increased from 83.3% to 100%. With O 3 /HCHO ratio of 8, the mineralization efficiency of HCHO to CO 2 was 86.1%. At 25°C, the p-type oxide semiconductor (Mn 0.5 Ce 0.5 O 2 ) exhibited an excellent ozone decomposition efficiency of 99.2%, which significantly exceeded that of n-type oxide semiconductors such as TiO 2 , which had a low ozone decomposition efficiency (9.81%). At a GHSV of 10,000 hr − 1 , [O 3 ]/[HCHO] = 3 and temperature of 25°C, a high HCHO removal efficiency (≥ 81.2%) was maintained throughout the durability test of 80 hr, indicating the long-term stability of the catalyst for HCHO removal.
Databáze: OpenAIRE
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