The formation and growth of calcium sulfate crystals through oxidation of SO₂by O₃on size-resolved calcium carbonate

Abstract

The heterogeneous formation pathway of rod-like calcium sulfate crystals in the atmosphere.

Effects of NO<sub>2</sub> and C<sub>3</sub>H<sub>6</sub> on the heterogeneous oxidation of SO<sub>2</sub> on TiO<sub>2</sub> in the presence or absence of UV irradiation

“…The heterogeneous reaction of SO 2 on mineral dust can be promoted by gaseous oxidants. For example, SO 2 could be oxidized into sulfate by O 3 on the surface of CaCO 3 particles (Li et al, 2006;Zhang et al, 2018). Similar results were obtained when introducing H 2 O 2 into the heterogeneous oxidation system (Capaldo et al, 1999;Jayne et al, 1990).…”

Effects of NO<sub>2</sub> and C<sub>3</sub>H<sub>6</sub> on the heterogeneous oxidation of SO<sub>2</sub> on TiO<sub>2</sub> in the presence or absence of UV–Vis irradiation

“…With reaction time increasing, the adsorption sites on the surface became saturated with sulfite and prevented SO 2 from adsorbing on the particles further. Coexisting NO 2 could enhance the heterogeneous formation of sulfate with much lower concentrations (200 ppb) relative to previous studies (∼ 100 ppm) (Ma et al, 2008;Liu et al, 2012;Zhao et al, 2018). The presence of C 3 H 6 had little effect on sulfate formation in the heterogeneous reaction of SO 2 but suppressed sulfate formation in the heterogeneous reaction of SO 2 and NO 2 , because C 3 H 6 could react ROS generated in the adsorption of NO 2 .…”

“…Therefore, NO 2 was proposed to act as a catalyst in the oxidation of SO 2 by O 2 , in which the intermediates observed in the spectra, i.e., nitrogen tetroxide (N 2 O 4 ), might play an important role (Ma et al, 2008). This synergistic effect between SO 2 and NO 2 was further observed on many other mineral oxides such as CaO, α-Fe 2 O 3 , ZnO, MgO, α-Al 2 O 3 , and TiO 2 (Liu et al, 2012;Ma et al, 2017;Zhao et al, 2018;. These effects were confirmed in smog chamber studies and field observations of heavy haze in China, and they were proposed to be an important reason for the rapid growth of sulfate in haze events (He et al, 2014;Ma et al, 2018;Wang et al, 2014a;Chu et al, 2016).…”

Acidity and the multiphase chemistry of atmospheric aqueous particles and clouds

“…Typically, the participating nucleophiles are H 2 O, HSO − 4 , and SO 2− 4 , although amines (Stropoli and Elrod, 2015) and alcohols (Surratt et al, 2010;Piletic et al, 2013) can also contribute. A nucleophilic attack by H 2 O results in hydrolysis and polyol formation, thus explaining the presence of isoprene-derived tetrols in particles (Kourtchev et al, 2005;Xia and Hopke, 2006;Liang et al, 2012;Zhang et al, 2013). The hydrolysis of epoxides catalyzed by NH + 4 can only be important in less acidic aerosol solutions due to the orders of magnitude of lower-rate coefficients (Noziere et al, 2018).…”