Reactive uptake of acetic acid on calcite and nitric acid reacted calcite aerosol in an environmental reaction chamber

Abstract

The heterogeneous chemistry of gas-phase acetic acid with CaCO(3)(calcite) aerosol was studied under varying conditions of relative humidity (RH) in an environmental reaction chamber. Infrared spectroscopy showed the loss of gas-phase reactant and the appearance of a gaseous product species, CO(2). The acetic acid is observed to adsorb onto the calcite aerosol through both a fast and a slow uptake channel. While the fast channel is relatively independent of RH, the slow channel exhibits enhanced uptake and reaction as the RH is increased. In additional experiments, the calcite aerosol was exposed to both nitric and acetic acids in the presence of water vapor. The rapid conversion of the particulate carbonate to nitrate and subsequent deliquescence significantly enhances the uptake and reaction of acetic acid. These results suggest a possible mechanism for observed correlations between particulate nitrate and organic acids in the atmosphere. Calcium rich mineral dust may be an important sink for simple organic acids.

Synergistic effect in the humidifying process of atmospheric relevant calcium nitrate, calcite and oxalic acid mixtures

“…Because the product Ca(NO 3 ) 2 is very hygroscopic which enhanced absorption of water and consequently enhanced further uptake of HNO 3 or NO 2 (Al-Abadleh et al, 2003;Liu et al, 2008). The presence of Ca(NO 3 ) 2 can also promote the reactions between calcite and other acidic gases by providing an aqueous circumstance under humid condition (Prince et al, 2008). When insoluble calcium salts (e.g.…”

“…Due to its alkalescence, calcite has a significant neutralization effect on atmospheric acidic constituents, such as H 2 SO 4 , SO 2 , HNO 3 , NO 2 , and carboxylic acids (Dentener et al, 1996;Prince et al, 2008;Usher et al, 2003). These reactions not only change atmospheric trace gas distributions but also modify the composition and mixing state of particles, and consequently affect the thermodynamic and optical properties of particles.…”

“…For example, Ca(NO 3 ) 2 /CaCO 3 mixture formed from heterogeneous reaction between nitric acid and calcite has been observed in both field measurement and laboratory studies (Al-Abadleh et al, 2003;Laskin et al, 2005;. Soluble calcium nitrate formed on calcite surface enormously enhanced the hygroscopicity of the mixtures and reactivity to other soluble gases (Al-Abadleh et al, 2003;Liu et al, 2008;Prince et al, 2008). However, little is known about the interaction between calcite and HOx in mixed mineral dust particles.…”

Long-range atmospheric transport of volatile monocarboxylic acids with Asian dust over a high mountain snow site, central Japan

“…This dust event was also recognized by the lidar observations at Niigata, Sendai, and Tsukuba in Japan. We estimated that Asian dust events observed on 10 December, 1 January, and 2 February during 2008and 6, 25-26 and 31 December, and 22-24 February during 2010 (Table 1).…”

“…Based on a good correlation between monocarboxylic acids and nss-Ca 2+ , it is very likely that organic acids in aerosols exist in the form of salts such as Ca(HCOO) 2 , Ca(HCOO)(CH 3 COO), and/or Ca(CH 3 COO) 2 . Prince et al (2008) reported that gas-phase acetic acid is adsorbed on the surface of calcite (CaCO 3 ), a major mineral of dust particles. Acetic acid can form calcium acetate in the atmosphere (Alexander et al, 2015).…”