硝酸盐对羰基硫与气溶胶表面非均相反应的影响

Effects of Nitrates on the Heterogeneous Reaction of Carbonyl Sulfide on Model Aerosols

利用原位漫反射傅里叶红外光谱(DRIFTS)对硝酸盐与α-Fe_2O_3形成的混合气溶胶与羰基硫(COS)的非均相反应进行研究,并比较了不同硝酸盐(NaNO_3、KNO_3和NH_4NO_3)和α-Fe_2O_3的混合物与COS反应的情况.结果表明:NaNO_3质量分数为4%的混合颗粒物与COS反应具有最高的反应活性,相比纯α-Fe_2O_3的反应速率提高了约5倍;含等质量分数(24%)硝酸盐的混合物和纯α-Fe_2O_3对COS的转化能力依次为:α-Fe_2O_3/KNO_3>α-Fe_2O_3/NaNO_3>α-Fe_2O_3/NH_4NO_3>α-Fe_2O_3,而纯NaNO_3、KNO_3和NH_4NO_3颗粒与COS不发生反应,说明硝酸盐的存在很大程度上提高了COS在α-Fe_2O_3颗粒物表面的转化能力.

The heterogeneous reaction of carbonyl sulfide （COS） on hematite particles in the presence of nitrate was investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS）. For sodium nitrate-containing samples, the hematite sample containing NaNO3 with mass fraction of 4% gave the highest reaction rate, which was about 5 times higher than that of hematite. For the particles containing nitrate at the same mass fraction （24%）the reactivity in descending order was a-Fe2O3/KNO3〉a-Fe2O3/NaNO3〉a-Fe2O3/NH4NO3〉a-Fe2O3 and a-Fe2O3. No uptake of COS was observed for the pure NaNO3, KNO3 and NH,NO3 samples. These results indicate that the added nitrate increased the COS conversion ability ofa-Fe2O3 particles.