CRAEMS: Fundamental Studies of Nanoparticle Formation in Air Pollution

伍斯特理工学院环境分子科学合作研究活动（CRAEMS）奖由化学部特别项目办公室支持。 Barbara Wyslouzil因对空气污染中纳米颗粒形成的基础研究而获得该奖项的支持。 还通过子奖项向特拉华州大学的道格·多伦、默里约翰斯顿、王海和安东尼·韦克斯勒提供支持。将进行一个综合的实验和理论计划，以了解在分子水平上，纳米颗粒形成的过程是相关的空气污染。将讨论的主题是（1）水溶液系统中的成核，（2）碳烟开始，（3）碳烟和金属在燃烧过程中的相互作用。水、水/酒精和水/硝酸气溶胶将在超音速喷嘴中产生，并通过小角中子散射和FTIR表征。 分子模拟技术将被应用于计算成核速率和解决重要的非平衡效应。将在平焰燃烧器中产生烟尘颗粒，并通过使用扫描移动粒度仪进行采样来表征。 尺寸分布将比较小角中子和X射线散射实验得出的。将通过质谱法测定颗粒的分子组成。金属和烟灰之间的反应将通过从乙烯-氧气火焰中产生粒子来研究，并以二茂铁为种子。 本课程将发展包含金属氧化物粒子形成与碳沉积之分子机制的数学模型。粒子成核是许多环境与工业制程中的关键步骤。 耐火颗粒是在燃烧和冶金过程中形成的，而酸水滴是在烟道气、火山羽流和大气中的光化学反应中产生的。这项研究将有助于确定它们形成的机制以及它们在空气污染中所起的作用。

This Collaborative Research Activities in Environmental Molecular Science (CRAEMS) Award to Worcester Polytechnic Institute is supported by the Special Projects Office in the Chemistry Division. Barbara Wyslouzil is supported by this award for the fundamental study of nanoparticle formation in air pollution. Support is also provided to Doug Doren, Murray Johnston, Hai Wang, and Anthony Wexler at the University of Delaware through subawards. An integrated experimental and theoretical program will be carried out to understand, at a molecular level, the processes of nanoparticle formation that are relevant to air pollution. The topics that will be addressed are (1) nucleation in aqueous systems, (2) soot inception, and (3) the interaction between soot and metals during combustion. Water, water/alcohol and water/nitric acid aerosols will be generated in a supersonic nozzle and characterized by small angle neutron scattering and FTIR. Molecular simulation techniques will be applied to calculate nucleation rates and to address important non-equilibrium effects. Soot particles will be generated in a flat flame burner and characterized by sampling with a scanning mobility particle sizer. Size distributions will be compared to those derived from small angle neutron and x-ray scattering experiments. Molecular composition of the particles will be determined by mass spectrometry. The reaction between metals and soot will be studied by generating particles from ethylene-oxygen flames, seeded with ferrocene. Mathematical models will be developed that incorporate molecular mechanisms of metal oxide particle formation and carbon deposition.Particle nucleation is a key step in many environmental and industrial processes. Refractory particles are formed in combustion and metallurgical processes, while acid-water droplets are produced in stack gases, volcanic plumes and in photochemical reactions in the atmosphere. This research will help define the mechanisms by which they are formed and the role they play in air pollution.