Comparison of hydrolysis and oxidation reactions of carbonyl sulfide on particle matter

Abstract

Reactions of carbonyl sulfide (OCS) on atmospheric particles were investigated in a flowing system using Fourier transform infrared (FTIR) at 293 K. Results show that OCS could be slowly oxidized and hydrolyzed on atmospheric particles. As a simplified model, alumina (Al 2 O 3 ) was used to further compare the two reactions and the results indicate that hydrolysis reaction of OCS has an advantage over oxidation reaction to take place at a given time and that heterogeneous reactions of OCS on particles at atmospheric conditions may include oxidation and hydrolysis reactions. To explore the effect of metals on hydrolysis reaction, zinc (Zn), iron (Fe), calcium (Ca), and magnesium (Mg) supported on Al 2 O 3 were prepared by incipient wetness method, and the results suggest that all metal oxides significantly enhance the initial intrinsic activity of OCS when compared with unmodified Al 2 O 3 . The Zn-modified Al 2 O 3 gives a significant increase of CO 2 produced throughout the time-scale of these experiments and the possible reaction processes are proposed. 