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

NIRT：燃烧产生的奈米微粒--过渡金属在奈米微粒与污染物形成中的角色CTS-0404314本计画的研究内容包括：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，以及2.）在有机污染物的形成中，金属氧化物凝聚在生长的纳米颗粒上的作用。 Ni和Cu已被确定为用于初步研究的重要金属。 正在使用各种实验技术研究它们的氧化物在一系列条件下的反应性。树枝状合成技术用于产生具有和不具有相关碳质层的1-3 nm金属氧化物纳米颗粒;溶胶-凝胶技术用于在碳和二氧化硅上产生薄金属氧化物膜。 使用高温流动反应器结合GC-MS，EPR和FTIR分析，研究了在氧化和热解条件下从200至1100 C的有机化学品与这些纳米颗粒替代物的反应。采用HPLC-UV吸收研究了金属催化的PAH形成。 的性质的金属氧化物和它们的化学结合的特征在于使用X射线光谱技术在路易斯安那州立大学同步加速器设施。从头算建模技术被用来评估纳米颗粒的几何形状，反应位点，可能的反应机制，以及它们如何作为颗粒尺寸和金属身份的函数而变化。据估计，美国每年有超过65万人因暴露于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，已被证明会在暴露人群中引发心肺疾病和癌症。 然而，直到最近才意识到，亚微米燃烧产生的纳米颗粒是大多数死亡和相关疾病的可能原因（单独或与其他污染物结合）。 尽管NIH和EPA已经启动了健康影响研究计划，但致病因子仍然未知，并且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。 该计划的推动力是实用的，即了解燃烧产生的纳米颗粒的起源和性质，以便将其对环境的影响降至最低。我们的目标是有助于了解影响燃烧产生的纳米颗粒的健康效应的化学因素，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.