Shen Xiao-Li, Chen Zhong-Ming, Zhao Yue, Huang Dao
State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2012 Nov;32(11):2946-9.
Glyoxal is one of the most important volatile organic compounds in the atmosphere. The reactions of glyoxal in the gaseous and aqueous phases and on the surfaces of secondary inorganic acidic aerosols can lead to atmospheric secondary organic aerosol (SOA) formation. However, up to now, there is no report on the heterogeneous reaction of glyoxal on dust particles. The present work investigated the heterogeneous absorption and transformation mechanisms of glyoxal on SiO2 and alpha-Al2 O3 particles. The progress of heterogeneous reaction conducted in the flow tube reactor was in situ monitored by transmission Fourier transform Infrared (T-FTIR). The reaction products were analyzed by combining T-FTIR with HPLC, IC, and HPLC-MS. It was found that oligomers form after the glyoxal is absorbed onto the particles (SiO2 and alpha-Al2 O3); and for alpha-Al2 O3, organic acids form on the particle surface in absence of illumination and oxidants. Moreover, it was revealed that water vapor favors the formation of oligomers, but suppresses the production of organic acids. These findings help further understand the SOA formation from the heterogeneous reaction of glyoxal on dust in the atmosphere.
