Project 1: Formation and Reactions of Environmentally Persistent Free Radicals in

项目1：环境持久性自由基的形成和反应

• 批准号: 8379655
• 负责人: Barry Dellinger
• 金额: $ 26.02万
• 依托单位: LOUISIANA STATE UNIV A&M COL BATON ROUGE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8379655
• 关键词: Affect; Binding; Biochemistry; Biological; Breathing; Caliber; Cardiac; Chemistry; Chlorobenzene; Chlorophenols; Collaborations; Complex; Copper; Data; Defect; Devices; Electron Spin Resonance Spectroscopy; Electron Transport; Environment; Free Radical Formation; Free Radicals; Fright; Functional disorder; Gases; Genetic Recombination; Hazardous Substances; Hazardous Waste; Hydroxyl Radical; Kinetics; Knowledge; Laboratories; Lead; Literature; Lung; Measurement; Measures; Mediating; Metals; Modeling; Modification; Molecular; Oxidation-Reduction; Oxidative Stress; Oxides; Oxygen; Particle Size; Particulate Matter; Pathway interactions; Pentachlorophenol; Phase; Reaction; Relative (related person); Reporting; Research; Roentgen Rays; Role; Sampling; Silicon Dioxide; Soil; Soot; Source; Spectroscopy, Fourier Transform Infrared; Structure; Superfund; Surface; System; Techniques; Toxic effect; Transition Elements; Wood material; base; chemical property; chlorobenzene; density; dibenzo(1,4)dioxin; dibenzofuran; fly ash; innovation; iron oxide; metal complex; metal oxide; particle; phenoxy radical; pollutant; reaction rate; remediation; semiquinone radicals; superfund site; theories

Environmentally persistent free radicals (EPFRs) are formed on the surfaces of transition metal-containing particles by chemisorption of a molecular precursor and electron transfer from the organic to the metal, resulting in reduction of the metal and formation of the EPFR. Association of some radicals with the metal increases their stability and reduces their rate of reaction with oxygen such that they can persist for several days in the environment. EPFRs have been found associated with soot and fly-ash produced from the combustion of hazardous wastes and Superfund soils from a former wood-treatment facility contaminated with pentachlorophenol. EPFRs are formed in high concentrations in the thermal and cool-zones of incinerators and other thermal treatment devices for remediation of Superfund sites where they can also react, primarily by radical-radical recombination, to form polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This project explores the origin and fate of EPFRs in thermal treatment devices through four Specific Aims: 1) Identify the mechanisms of EPFR formation and stabilization on transition metal surfaces; 2) Determine the role of iron oxide-containing, combustion-generated particles in the formation of PCDD/F from chlorobenzenes and chlorophenols; 3) Assess the effect of particle size on EPFR and PCDD/F formation for Fe2O3 - containing particles; and 4) Develop Reaction Kinetic Models of Surface-Mediated Formation of EPFRs and PCDD/Fs. This project provides the basic chemistry needed for the other projects in the Center. Collaboration with Project 6 will lead to understanding how the structure and chemical properties of particles affect EPFR formation and reactivity. It provides the background for study of formation and stabilization of EPFRs in contaminated Superfund soils in Project 3. It also provides the basic biological chemistry necessary to understand the cardiac and pulmonary dysfunction induced by inhalation of EPFRs demonstrated in Biomedical Projects 2, 4, and 5. Collaboration with the Oxidative Stress Core, Materials Core, and Computational Core has already shown EPFR-particle systems participate in long chain cycles in biological media producing hydroxyl radical that initiates oxidative stress in the exposed host.

通过分子前体的化学吸附和电子从有机物转移到金属，环境持久性自由基（EPFR）在含过渡金属的颗粒表面形成，导致金属还原并形成EPFR。一些自由基与金属的结合增加了它们的稳定性并降低了它们与氧气的反应速率，使得它们可以在环境中持续数天。 EPFR 被发现与危险废物燃烧产生的烟灰和飞灰以及来自受污染的前木材处理设施的超级基金土壤有关 与五氯苯酚。 EPFR 在焚烧炉和其他用于修复超级基金场地的热处理装置的热区和冷区中形成高浓度，它们也可以在这些装置中发生反应，主要通过自由基-自由基重组，形成多氯二苯并-对-二恶英和二苯并呋喃 (PCDD) /Fs）。该项目通过四个具体目标探讨热处理设备中 EPFR 的起源和命运： 1) 确定 EPFR 形成和转变稳定的机制 金属表面； 2) 确定含氧化铁的燃烧产生的颗粒在氯苯和氯酚形成 PCDD/F 中的作用； 3) 评估含 Fe2O3 颗粒的粒径对 EPFR 和 PCDD/F 形成的影响； 4) 开发表面介导的 EPFR 和 PCDD/F 形成的反应动力学模型。该项目提供了中心其他项目所需的基础化学。与项目 6 的合作将有助于了解颗粒的结构和化学性质如何影响 EPFR 的形成和反应性。为研究提供了背景 项目 3 中受污染的超级基金土壤中 EPFR 的形成和稳定。它还提供了了解生物医学项目 2、4 和 5 中演示的吸入 EPFR 引起的心肺功能障碍所需的基本生物化学。与氧化应激核心的合作、材料核心和计算核心已经表明 EPFR 颗粒系统参与生物介质中的长链循环，产生羟基自由基，从而在暴露的宿主中引发氧化应激。