Unveiling the Role of Carbonate Radical Anions in Dust‐Driven SO2 Oxidation
Yangyang LiuTao WangQiuyue GeWenbo YouKejian LiWei WangLifang XieLongqian WangXiaozhong FangXuejun RuanLe YangRunbo WangLiwu Zhang
2
Citation
166
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract Carbonate radical anion () is generally overlooked in atmospheric chemistry. Our recent work emphasizes the important role of carbonate radicals produced on mineral dust surfaces in fast sulfate production under solar irradiation in the presence of CO 2 at specifically low RH and light intensity. Yet so far how involves and affects secondary sulfate production under diverse RH, light intensity, and complex constituent matrix remains unknown, which essentially limits our comprehensive knowledge of initiated SO 2 oxidation scheme in the atmosphere. Herein, we explored the heterogeneous SO 2 oxidation over both model and authentic dust and clays in the presence of CO 2 at atmospheric relevant RHs and light intensities. Interestingly, we observe that CO 2 promotes sulfate yield over authentic dust and clays at atmospheric‐relevant RH and light intensity. This observation relates to the favorable kinetic between SO 2 oxidation and while auto‐quenching of these radical ions is largely minimized due to the sufficient sites of crustal constituents. Furthermore, employing a suite of authentic dust and machine learning strategies, we evaluated the relative importance of each constituent within airborne minerals or clays as well as environmental conditions including relative humidity, light intensity, and CO 2 concentration in affecting SO 2 uptake capability. On this basis, sulfate formation mediated by dust‐driven pathway, accounting for nearly ∼20.9% of overall contribution by the end of this century during some pollution episodes, even higher than gas‐phase (∼16.9%), will be increased by 163% if CO 2 ‐initiated SO 2 oxidation scheme is incorporated.Carbon isotopes of pedogenic carbonate are often used to study paleoenvironments, but the existence of detrital carbonate changes the carbon isotopic composition. To develop an experimental method to determine existence of detrital carbonate in carbonate nodules, and to avoid it during isotope analysis, 23 pedogenic carbonate nodules in Miocene loess from the Loess Plateau of China were studied through micromorphology and carbon isotope analysis. The difference in carbon isotopic composition between matrix carbonate (B) and pore carbonate (A) (δ 13C(B-A)) ranges from 0.27‰ to 0.44‰ in nodules containing detrital carbonate and–0.16‰ to 0.13‰ in nodules where detrital carbonate is absent. The latter is within measurement error, but the former is beyond it. Here we propose an isotopic approach to determine if nodules contain detrital carbonate: if δ 13C(B-A) is within the measurement error, the nodules do not contain detrital carbonate, and vice versa. We suggest that it is better to analyze pore carbonate instead of matrix carbonate when using carbon isotope of carbonate nodules to reconstruct paleoenvironments.
Carbonate minerals
Carbon fibers
Cite
Citations (0)