SO_2与矿物气溶胶组分α-Fe_2O_3的光化学反应机制

A mechanism observation on the photochemical reaction between SO_2 and α-Fe_2O_3.

利用红外漫反射光谱仪(DRIFTS)研究了SO2在α-Fe2O3表面上的多相光化学反应.结果表明,在无光照和光照条件下,α-Fe2O3表面均生成硫酸盐,但硫酸盐的生成量和生成速率不同.模拟太阳光照射下,反应4hBET吸附系数为9.61×10-9,无光照条件下为1.39×10-8;光照条件下硫酸盐生成量低于无光照条件.当O2的体积浓度<21%时,增加O2浓度促进了硫酸盐的生成.用草酸和腐殖酸处理后的α-Fe2O3与SO2反应,由于α-Fe2O3表面反应活性位被占据,导致硫酸盐生成量急剧减少.

The attempt has been done to observe photochemical oxidation of gaseous SO2 on α-Fe2O3 using a in suit diffuse reflectance infrared Fourier transform spectroscopy（DRIFTS）. SO2 could be oxidized to form sulfate on the surface of α-Fe2O3 both under light irradiation and in the dark. However, the rate and quantity of sulfate are different, and the BET uptake coefficients are 9.61 ×10^-9 and 1.39× 10^-8 under the irradiation and in the dark, respectively. The amount of sulfate formed under irradiation is slightly less than the one in the dark. When oxygen proportion was less than 21%, O2 could enhance SO2 uptake on the surface of α-Fe2O3. In the case of α-Fe2O3 pretreated by oxalic acid and humic acid, the yield of sulfate decreased swiftly, which is due to the occupation of the active sites on the surface of α-Fe2O3.