Single Droplet Tweezer Revealing the Reaction Mechanism of Mn(II)-Catalyzed SO2 Oxidation

• DOI: 10.1021/acs.est.4c00309
• Publication Date: 2024-03-06T15:52:00Z
• Authors: Xue Cao; Yu-Xin Liu; Qishen Huang; Zhe Chen; Jiuyi Sun; Jian Sun; Shu-Feng Pang; Pai Liu; Weigang Wang; Yun-Hong Zhang; Maofa Ge
• Keywords: Parametrization (atmospheric modeling); Reaction rate

Sulfate aerosol is one of the major components secondary fine particulate matter in urban haze that has crucial impacts on social economy and public health. Among atmospheric sulfate sources, Mn(II)-catalyzed SO2 oxidation surfaces been regarded as a dominating one. In this work, we measured reaction kinetics single droplets using an optical tweezer. We show occurs at Mn(II)-active sites surface, per piecewise kinetic formulation, characterized by threshold surface Mn(II) concentration gaseous concentration. When lower than value, rate first order with respect to both SO2, agreeing our traditional knowledge. But when above threshold, becomes independent concentration, greater unity. The can serve tool estimate formation based field observation, established parametrization corrects these calculations. This framework for holds promising potential generalization various heterogeneous pathways.