Impact of adsorbed nitrate on the heterogeneous conversion of SO2 on α-Fe2O3 in the absence and presence of simulated solar irradiation
Impact of adsorbed nitrate on the heterogeneous conversion of SO2 on α-Fe2O3 in the absence and presence of simulated solar irradiation
复制标题
在存在和不存在模拟太阳辐射的情况下，吸附硝酸盐对 α-Fe2O3 上 SO2 异相转化的影响
DOI：
10.1016/j.scitotenv.2018.08.295
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发表时间：
2018
影响因子：
9.8
通讯作者：
Shicheng Zhang
中科院分区：
文献类型：
--
作者：
Chengtian Du;Lingdong Kong;Assiya Zhanzakova;Songying Tong;Xin Yang;LinWang;Hongbo Fu;Tiantao Cheng;Jianmin Chen;Shicheng Zhang
吸附的硝酸盐在大气中普遍存在，它可以进行光解产生氧化活性自由基。硝酸盐的光解可能与大气气态污染物的氧化转化相耦合。然而，对所涉及的过程仍然知之甚少。采用原位漫反射红外光谱（DRIFTS）技术，研究了模拟太阳光照射条件下，NO3-对α-Fe 2 O3上SO2非均相氧化反应的影响.结果表明，对于未吸附硝酸盐的α-Fe 2 O3颗粒，湿颗粒上吸附态硫酸盐的形成比干颗粒上强。同时，由于α-Fe 2 O3是典型的光催化剂，光也能促进SO2在干颗粒上的多相转化和硫酸盐的生成。而在光照条件下，SO2在潮湿α-Fe 2 O3颗粒上的非均相转化受到一定程度的抑制，表明发生了光诱导还原溶解。对于SO2在吸附有硝酸盐的α-Fe 2 O3颗粒上的非均相转化，湿颗粒上硫酸盐的生成量仍高于干颗粒上。对于吸附有硝酸盐的干燥α-Fe 2 O3颗粒，光照促进了吸附态硫酸盐的形成。对于吸附有硝酸盐的潮湿α-Fe 2 O3颗粒，光照下SO2的非均相转化比无光照下强，说明吸附的硝酸盐的光解与SO2的氧化和硫酸盐的生成耦合。在引入SO2的过程中，观察到了吸附态硝酸盐的消耗和吸附态N2 O 4的形成。提出了NO_3 ~-对SO_2在α-Fe_2O_3颗粒上非均相转化影响的可能机制，并讨论了这些结果的大气意义。
Adsorbed nitrate is ubiquitous in the atmosphere, and it can undergo photolysis to produce oxidizing active radicals. Nitrate photolysis may be coupled with the oxidation conversions of atmospheric gaseous pollutants. However, the processes involved remain poorly understood. In this study, the impact of adsorbed nitrate on the heterogeneous oxidation of SO2on α-Fe2O3was investigated in the absence and presence of simulated solar irradiation by using in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that for α-Fe2O3particles with no adsorbed nitrate, the formation of adsorbed sulfate on humid particles is stronger than that on dry particles. Meanwhile, light can also promote the heterogeneous conversion of SO2and the formation of sulfate on dry particles because α-Fe2O3is a typical photocatalyst. However, the heterogeneous conversion of SO2on humid α-Fe2O3particles is somewhat suppressed under light, suggesting the occurrence of photoinduced reductive dissolution. For the heterogeneous conversion of SO2on α-Fe2O3particles with adsorbed nitrate, the formation of sulfate on humid particles is still higher than that on dry particles. For the dry α-Fe2O3particles with adsorbed nitrate, light promotes the formation of adsorbed sulfate. For the humid α-Fe2O3particles with adsorbed nitrate, the heterogeneous conversion of SO2under light is stronger than that under no light, indicating that the photolysis of adsorbed nitrate is coupled with the oxidation of SO2and the formation of sulfate. The consumption of adsorbed nitrate and the formation of adsorbed N2O4are observed during the introduction of SO2. A possible mechanism for the impact of adsorbed nitrate on the heterogeneous conversion of SO2on α-Fe2O3particles is proposed, and atmospheric implications based on these results are discussed.