Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China.
Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China; Key Laboratory of National Land Space Planning and Disaster Emergency Management of Inner Mongolia, School of Resources, Environment and Architectural Engineering, Chifeng University, Chifeng, 024000, China.
Chemosphere. 2022 Sep;303(Pt 1):134854. doi: 10.1016/j.chemosphere.2022.134854. Epub 2022 May 6.
Environmentally persistent free radicals (EPFRs) have been recognized as harmful and persistent environmental pollutants. In polluted regions, many acidic and basic atmospheric pollutants, which are present at high concentrations, may influence the extent of the formation of EPFRs. In the present paper, density functional theory (DFT) and ab-initio molecular dynamics (AIMD) calculations were performed to investigate the formation mechanisms of EPFRs with the influence of the acidic pollutants sulfuric acid (SA), nitric acid (NA), organic acid (OA), and the basic pollutants, ammonia (A), dimethylamine (DMA) on α-AlO (0001) surface. Results indicate that both acidic and basic pollutants can enhance the formation of EPFRs by acting as "bridge" or "semi-bridge" roles by proceeding via a barrierless process. Acidic pollutants enhance the formation of EPFRs by first transferring its hydrogen atom to the α-AlO surface and subsequently reacting with phenol to form an EPFR. In contrast, basic pollutants enhance the formation of EPFRs by first abstracting a hydrogen atom from phenol to form a phenoxy EPFR and eventually interacting with the α-AlO surface. These new mechanistic insights will inform in understanding the abundant EPFRs in polluted regions with high mass concentrations of acidic and basic pollutants.
环境持久性自由基（EPFRs）已被认为是有害且持久的环境污染物。在污染地区，许多高浓度存在的酸性和碱性大气污染物可能会影响 EPFRs 的形成程度。在本文中，我们采用密度泛函理论（DFT）和从头算分子动力学（AIMD）计算方法，研究了酸性污染物硫酸（SA）、硝酸（NA）、有机酸（OA）和碱性污染物氨（A）、二甲胺（DMA）对α-AlO（0001）表面上 EPFRs 形成机制的影响。结果表明，酸性和碱性污染物都可以通过无势垒过程作为“桥”或“半桥”作用来增强 EPFRs 的形成。酸性污染物首先将其氢原子转移到α-AlO 表面，然后与苯酚反应形成 EPFR，从而增强 EPFRs 的形成。相比之下，碱性污染物通过首先从苯酚中提取一个氢原子形成酚氧自由基 EPFR，最终与α-AlO 表面相互作用来增强 EPFRs 的形成。这些新的机理见解将有助于理解在高浓度酸性和碱性污染物存在的污染地区中丰富的 EPFRs。
