Catalytic oxidation of gaseous PCDD/Fs with ozone over iron oxide catalysts.
Catalytic oxidation of PCDD/Fs (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans) with ozone (catalytic ozonation) over nano-sized iron oxides (denoted as FexOy) was carried out at temperature of 120-180 degrees C. The effects of operating temperature, ozone concentration, space velocity (SV) and water vapor contents on PCDD/F removal and destruction efficiencies via catalytic ozonation were investigated. High activity of the iron oxide catalyst towards PCDD/F decomposition was observed even at low temperatures with the aid of ozone. The PCDD/F removal and destruction efficiencies achieved with FexOy/O3 at 180 degrees C reach 94% and 91%, respectively. In the absence of ozone, the destruction efficiencies of all PCDD/F congeners are below 20% and decrease with increasing chlorination level of PCDD/F congener at lower temperature (120 degrees C). However, in the presence of ozone, the destruction efficiencies of all PCDD/F congeners are over 80% on FexOy/O3 at 180 degrees C. Higher temperature and ozone addition increase the activity of iron oxide for the decomposition of PCDD/Fs. Additionally, in the presence of 5% water vapor, the destruction efficiency of the PCDD/Fs is above 90% even at lower operating temperature (150 degrees C). It indicates that the presence of appropriate amount of water vapor enhances the catalytic activity for the decomposition of gas-phase PCDD/Fs.
Wang
Hou Chuan
HC
Graduate Institute of Environmental Engineering, National Central University, Chungli 320, Taiwan.
Chang
Shu Hao
SH
Hung
Pao Chang
PC
Hwang
Jyh Feng
JF
Chang
Moo Been
MB
D000397:Air Pollution / Q000032:analysis / Q000517:prevention & control; D001572:Benzofurans / Q000032:analysis* / Q000737:chemistry; D002384:Catalysis; D000072338:Dibenzofurans, Polychlorinated; D005290:Ferric Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010126:Ozone / Q000032:analysis* / Q000737:chemistry; D011078:Polychlorinated Biphenyls / Q000032:analysis* / Q000737:chemistry; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D013696:Temperature; D014835:Volatilization
D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D005290:Ferric Compounds; D000072317:Polychlorinated Dibenzodioxins; C000499:ferric oxide; D010126:Ozone; D011078:Polychlorinated Biphenyls