Kinetic model for gas-surface uptake experiments in a fast flow reactor
Egor V. Demidov, Alexei F. Khalizov
ACS MARM, Oral presentation, 2025
Abstract
Heterogeneous reactions affect the gas-phase composition of the atmosphere and are a critical pathway for processing of atmospheric aerosols. Such reactions are enabled by adsorption of gas-phase compounds onto aerosol particles or other environmental surfaces, which catalyse reactions that would otherwise not occur in gas phase. Kinetic parameters required to include heterogeneous reactions in atmospheric models are obtained in the laboratory, with experiments typically involving aerosol reactors or coated wall reactors. Since the experiments do not cover the broadest range of atmospheric conditions, assumptions are made about chemical mechanisms, which are then used to simulate heterogeneous chemistry. We present a numerical model for a coated wall reactor that can be used to derive rate constants for adsorption, desorption, and chemical reaction, along with the numbers of adsorptive and reactive sites from experimental measurements. The model performance is evaluated by comparing uptake probabilities calculated with the model against probabilities derived from experimental data.