Uptake Mechanism of Acetic Acid onto Natural Gobi Dust

Abstract

A challenge for understanding the environmental fate of atmospheric organic acids is to evaluate the impacts of their heterogeneous interactions with mineral dust aerosols in the atmosphere. However, the uptake of organic acids on authentic natural mineral dust is rarely investigated under atmosphere-relevant conditions. Herein, we investigated the uptake of acetic acid (AcA) onto a natural mineral dust from the Gobi Desert, Gobi dust, under atmosphere-relevant conditions, combining both the gas-phase and adsorbed-phase approaches. Gobi dust is evidenced to reversibly and irreversibly adsorb AcA molecules under both dry and humid conditions. In the presence of moisture, the fraction of the reversibly adsorbed AcA is promoted, which addresses the impact of water molecules with AcA on minerals. Physisorbed AcA monomer, dimer, and chemisorbed acetate are identified based on real-time surface monitoring using diffuse reflectance infrared Fourier transform spectroscopy. This study provides original data and insights into the impacts of heterogeneous interactions with mineral dust on the environmental fate of acetic acid. It also provides complete and visual mechanisms for a comprehensive understanding of the involved surface reactions. This study initiates the exploration of the heterogeneous kinetics of the fractions of reversibly and irreversibly adsorbed AcA on natural mineral dust under atmospheric conditions.

How Relevant Is It to Use Mineral Proxies to Mimic the Atmospheric Reactivity of Natural Dust Samples? A Reactivity Study Using SO2 as Probe Molecule

“…The sample was sieved (using a shaking siever) after collection and the fraction below 100 µm was used for the investigations. The Gobi mineral desert dust sample comes from the Gobi Desert, Ningxia Province, China (36 • 29 14.39 N 107 • 28 30.75 E) [46]. This area represents another major source of atmospheric mineral dust [44].…”

Unraveling the Uptake of Glyoxal on a Diversity of Natural Dusts and Surrogates: Linking Dust Composition to Glyoxal Uptake and Estimation of Atmospheric Lifetimes

“…Furthermore, mineral dust may act as cloud condensation nuclei (CCN) and ice nuclei (IN) leading to cloud formation. − The lifetime of mineral dust particles ranges from a few minutes to several days, mainly depending on their mass (sedimentation velocity). Mineral dust particles can interact/react with inorganic and organic pollutants (i.e., chemical processing or aging in this manuscript). − These interactions will likely affect both the global SOA budget and global/regional cloud formation potential or the interaction of mineral dust with radiation.…”

The Kinetics of Adsorption and Desorption of Selected Semivolatile Hydrocarbons and H2O Vapor on Two Mineral Dust Materials: A Molecular View

“…Considering acetic acid and a natural mineral dust sample from the Gobi desert as an example, Wang et al 14 came to the conclusion that there are a plethora of different adsorption sites, especially in the presence of atmospheric water. Using a simple breakthrough experiment coupled with gas-phase acetic acid detection using FTIR absorption, the total adsorption at saturation corresponded to a molecular monolayer in the absence of H 2 O vapor (2.7 × 10 14 molecules cm −2 ).…”