SO2在Fe2O3颗粒表面不同温度下非均相反应的实验模拟

A Simulated Heterogeneous Reaction of SO_2 on the Surface of Hematite at Different Temperatures

使用漫反射Fourier变换红外光谱(DFTIRS)、离子色谱(IC)及透射电子显微镜(TEM)对不同温度条件下SO2在α-Fe2O3颗粒表面的非均相反应过程进行实验模拟和监测,并分析了反应剧烈波段(8.7μm)的产物硫酸盐以及颗粒吸收和后向散射光学系数的变化.结果表明,在15-45℃内,硫酸盐生成量、生成速率以及吸收系数、后向散射系数都随反应温度的升高而呈现先增加后减少的趋势;同一反应温度下,硫酸盐生成速率随时间呈现先增大后减小,最后逐渐趋于稳定的演变;光学系数变化与硫酸盐生成量之间存在较好的指数关系.在当前全球气候变暖背景下,研究结果将对深入了解真实大气中SO2与矿尘非均相反应造成的气溶胶光学特性演变,以及定量评估其辐射强迫影响具有一定意义.

Changes of the sulfate product and optical coefficients during the heterogeneous reaction of SO2 on the surface of hematite at different temperatures were investigated using in situ diffuse reflectance Fourier transform infrared spectroscopy （DFTIRS）, ion chromatogram （IC）, and transmission electron microscopy （TEM）. Simulations revealed that within the ambient temperature of 15-45 ℃, the yield and velocity of sulfate product, absorption coefficient, and backward scattering coefficient firstly increased at 15-35 ℃ and then decreased at 35-45 ℃. At persistent temperature, the velocity of sulfate production showed an initial increase followed by a decrease and finally stabilized. There was a high exponential correlation between the optical coefficients and the amount of sulfate product generated. This result is important in understanding the heterogeneous reaction of SO2 on the surface of hematite in the environment and the assessment of this reaction＇s impact on sulfate production and radiative forcing, considering the phenomenon of global warming.