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Effects of SO 2 on selective catalytic reduction of NO with NH 3 over a TiO 2 photocatalyst

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ABSTRACT

The effect of SO2 gas was investigated on the activity of the photo-assisted selective catalytic reduction of nitrogen monoxide (NO) with ammonia (NH3) over a TiO2 photocatalyst in the presence of excess oxygen (photo-SCR). The introduction of SO2 (300 ppm) greatly decreased the activity of the photo-SCR at 373 K. The increment of the reaction temperature enhanced the resistance to SO2 gas, and at 553 K the conversion of NO was stable for at least 300 min of the reaction. X-ray diffraction, FTIR spectroscopy, thermogravimetry and differential thermal analysis, x-ray photoelectron spectroscopy (XPS), elemental analysis and N2 adsorption measurement revealed that the ammonium sulfate species were generated after the reaction. There was a strong negative correlation between the deposition amount of the ammonium sulfate species and the specific surface area. Based on the above relationship, we concluded that the deposition of the ammonium sulfate species decreased the specific surface area by plugging the pore structure of the catalyst, and the decrease of the specific surface area resulted in the deactivation of the catalyst.

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Time course of the photo-SCR in the presence or absence of SO2 gas at various temperatures. (◆) SO2: 0 ppm, 433 K, (▲) SO2: 300 ppm, 373 K, (■) SO2: 300 ppm, 433 K, (●) SO2: 300 ppm, 553 K. NO: 1000 ppm, NH3: 1000 ppm, O2: 2%, He: balance gas, flow rate: 200 mL min−1, GHSV: 100 000 h−1, light source: 200 W Hg–Xe lamp.
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Figure 1: Time course of the photo-SCR in the presence or absence of SO2 gas at various temperatures. (◆) SO2: 0 ppm, 433 K, (▲) SO2: 300 ppm, 373 K, (■) SO2: 300 ppm, 433 K, (●) SO2: 300 ppm, 553 K. NO: 1000 ppm, NH3: 1000 ppm, O2: 2%, He: balance gas, flow rate: 200 mL min−1, GHSV: 100 000 h−1, light source: 200 W Hg–Xe lamp.

Mentions: Figure 1 shows the time course of the photo-SCR over the TiO2 photocatalyst under illumination in the presence or absence of SO2 (300 ppm) gas at various temperatures. The conversion of NO was stable for 300 min at 433 K in the absence of SO2 gas, as we reported previously [14]. In the presence of SO2 at 433 K, the conversion of NO decreased with the reaction time, which indicates that the SO2 poisoned the catalyst, as in the case of the Mn-based catalysts [9]. The reaction temperature had a significant effect on the deactivation rate of the TiO2 photocatalyst. At 373 K, the conversion decreased more rapidly than at 433 K, and the conversion was almost stable for at least 300 min at 553 K. For simplification, the sample before the reaction was abbreviated as BR, and the samples after the reactions at 373 K, 433 K and 553 K were abbreivated as AR-373K, AR-433K and AR-553K, respectively.


Effects of SO 2 on selective catalytic reduction of NO with NH 3 over a TiO 2 photocatalyst
Time course of the photo-SCR in the presence or absence of SO2 gas at various temperatures. (◆) SO2: 0 ppm, 433 K, (▲) SO2: 300 ppm, 373 K, (■) SO2: 300 ppm, 433 K, (●) SO2: 300 ppm, 553 K. NO: 1000 ppm, NH3: 1000 ppm, O2: 2%, He: balance gas, flow rate: 200 mL min−1, GHSV: 100 000 h−1, light source: 200 W Hg–Xe lamp.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036466&req=5

Figure 1: Time course of the photo-SCR in the presence or absence of SO2 gas at various temperatures. (◆) SO2: 0 ppm, 433 K, (▲) SO2: 300 ppm, 373 K, (■) SO2: 300 ppm, 433 K, (●) SO2: 300 ppm, 553 K. NO: 1000 ppm, NH3: 1000 ppm, O2: 2%, He: balance gas, flow rate: 200 mL min−1, GHSV: 100 000 h−1, light source: 200 W Hg–Xe lamp.
Mentions: Figure 1 shows the time course of the photo-SCR over the TiO2 photocatalyst under illumination in the presence or absence of SO2 (300 ppm) gas at various temperatures. The conversion of NO was stable for 300 min at 433 K in the absence of SO2 gas, as we reported previously [14]. In the presence of SO2 at 433 K, the conversion of NO decreased with the reaction time, which indicates that the SO2 poisoned the catalyst, as in the case of the Mn-based catalysts [9]. The reaction temperature had a significant effect on the deactivation rate of the TiO2 photocatalyst. At 373 K, the conversion decreased more rapidly than at 433 K, and the conversion was almost stable for at least 300 min at 553 K. For simplification, the sample before the reaction was abbreviated as BR, and the samples after the reactions at 373 K, 433 K and 553 K were abbreivated as AR-373K, AR-433K and AR-553K, respectively.

View Article: PubMed Central - PubMed

ABSTRACT

The effect of SO2 gas was investigated on the activity of the photo-assisted selective catalytic reduction of nitrogen monoxide (NO) with ammonia (NH3) over a TiO2 photocatalyst in the presence of excess oxygen (photo-SCR). The introduction of SO2 (300 ppm) greatly decreased the activity of the photo-SCR at 373 K. The increment of the reaction temperature enhanced the resistance to SO2 gas, and at 553 K the conversion of NO was stable for at least 300 min of the reaction. X-ray diffraction, FTIR spectroscopy, thermogravimetry and differential thermal analysis, x-ray photoelectron spectroscopy (XPS), elemental analysis and N2 adsorption measurement revealed that the ammonium sulfate species were generated after the reaction. There was a strong negative correlation between the deposition amount of the ammonium sulfate species and the specific surface area. Based on the above relationship, we concluded that the deposition of the ammonium sulfate species decreased the specific surface area by plugging the pore structure of the catalyst, and the decrease of the specific surface area resulted in the deactivation of the catalyst.

No MeSH data available.


Related in: MedlinePlus