NIRT: Combustion-Generated Nanoparticles: The Role of Transition Metals in Nanoparticle and Pollutant Formation

燃烧生成的纳米颗粒--过渡金属在纳米颗粒和污染物形成中的作用CTS-0404314该项目涉及：1.燃烧生成的金属氧化物纳米颗粒在主要含碳纳米颗粒的形成/生长中的作用和2.凝聚在纳米颗粒上的金属氧化物在有机污染物形成中的作用。镍和铜已被确定为初步研究的重要金属。他们的氧化物在一系列条件下的反应性正在使用各种实验技术进行研究。树枝状合成技术被用来制备1-3纳米的金属氧化物纳米颗粒，包括和不带相关的碳质层；溶胶-凝胶技术被用来在碳和二氧化硅上形成薄的金属氧化物薄膜。利用高温流动反应装置，结合GC-MS、EPR和FTIR分析，研究了在200~1100℃的温度范围内，有机化合物与这些纳米粒子替代物在氧化和热解条件下的反应。用高效液相-紫外吸收法研究了金属催化的多环芳烃的生成。在路易斯安那州立大学的同步加速器设施中，使用X射线光谱技术对金属氧化物的性质及其化学结合进行了表征。从头算模拟技术被用来评估纳米颗粒的几何形状、反应位置、可能的反应机理，以及它们如何随着颗粒大小和金属特性的变化而变化。据估计，美国每年有超过65万人因接触空气中的细颗粒物而过早死亡。PM2.5被定义为平均空气动力学直径小于2.5微米的颗粒物，已被证明会在接触者中引发心肺疾病和癌症。然而，直到最近才意识到，燃烧产生的亚微米纳米颗粒可能是这些死亡和相关疾病的大多数(单独或与其他污染物结合)的原因。尽管NIH和EPA已经启动了健康效应研究计划，但致病因素仍然未知，由于缺乏对燃烧产生的纳米颗粒的复杂组成和反应性的了解，进展受到阻碍。这一计划的推动力是实际的，即。了解燃烧产生的纳米颗粒的来源和性质，以便将其对环境的影响降至最低。其目的是帮助了解影响燃烧产生的纳米颗粒对健康影响的化学因素，以便通过燃烧控制减轻或消除它们的影响。

NIRT: Combustion-Generated Nanoparticles--The Role of Transition Metals in Nanoparticle and Pollutant FormationCTS-0404314 This project addresses: 1.) The role of combustion-generated metal oxide nanoparticles in the formation/growth of primarily carbonaceous nanoparticles and 2.) The role of metal oxides condensed on growing nanoparticles in the formation of organic pollutants. Ni and Cu have been identified as important metals for initial study. The reactivity of their oxides under a range of conditions is being studied using a variety of experimental techniques. Dendrimeric synthesis techniques is used to create 1-3 nm metal oxide nanoparticles with and without associated carbonaceous layers; sol-gel techniques are used to create thin metal-oxide films on carbon and silica. The reactions of organic chemicals with these nanoparticle surrogates from 200 to 1100 C under oxidative and pyrolytic conditions are studied using a high-temperature flow reactor coupled with GC-MS, EPR, and FTIR analysis. Metal-catalyzed PAH formation is studied using HPLC-UV absorption. The nature of the metal oxides and their chemical binding is characterized using x-ray spectroscopic techniques at the LSU synchrotron facility. Ab initio modeling techniques are used to assess nanoparticle geometries, reaction sites, possible reaction mechanisms, and how they may vary as a function of particle size and metal identity. It has been estimated that over 650,000 people die prematurely in the US each year due to exposure to airborne fine particles. PM2.5, defined as particles with a mean aerodynamic diameter of less than 2.5 microns, have been shown to initiate cardiopulmonary disease and cancer in exposed populations. It has been realized only recently, however, that submicron, combustion-generated nanoparticles are the likely cause (alone or in combination with other pollutants) for the majority of these deaths and associated illnesses. Although health-effects research programs have been initiated by NIH and EPA, the causative agents remain unknown and progress is hindered by lack of understanding of the complex composition and reactivity of combustion-generated nanoparticles. The impetus of this program is practical, viz. to understand the origin and nature of combustion-generated nanoparticles so that their environmental impact can be minimized. The goal is contribute to the understanding of the chemical factors impacting the health effects of combustion-generated nanoparticles so that their effects can be mitigated or eliminated through combustion control.