NO_2在高岭石表面的非均相反应研究

Heterogeneous reaction of NO_2 on the surface of kaolinite particles

高岭石是典型的1∶1型层状结构的硅铝酸盐,研究其非均相反应对于了解粘土类矿物的非均相反应具有重要的意义.因此,试验以原位漫反射红外傅里叶变换光谱(DRIFTS)为研究手段,对NO2在高岭石表面的非均相反应进行了系统的研究.结果表明,NO2在高岭石表面发生歧化反应生成NO3-和NO2-.相对湿度对非均相反应具有重要影响,有水汽存在时会增加反应的持续能力,但相对湿度的增加会使摄取系数降低.在干态和湿态条件下,NO2在高岭石表面的反应机理不同,干态下为二级反应,湿态下为一级反应.

The studies of heterogeneous reactions on kaolinite,typically a 1：1 layered aluminosilicate,are necessary to understanding heterogeneous reactions on clay minerals.Using diffuse reflectance infrared Fourier transform spectroscopy（DRIFTS）,we investigated the heterogeneous reaction of NO2 on the surface of kaolinite particles.It is found that NO 3-and NO 2-were generated on the surface via the disproportionate reaction.Relative humidity played an important role in the heterogeneous reaction of NO2 and kaolinite.The reaction extence can be enhanced by the introduction of water vapor,while the uptake coefficient decreased as humidity increased.The reactions under the dry and humid conditions were determined to be second-order and first-order,respectively.