Investigation of PAH Photodegradation in Solutions

溶液中 PAH 光降解的研究

基本信息

批准号：
7933139
负责人：
KRISHNA L FOSTER
金额：
$ 6.27万
依托单位：
CALIFORNIA STATE UNIVERSITY LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-09-30 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7933139
关键词：
Alcohols Aldehydes Aromatic Compounds Aromatic Polycyclic Hydrocarbons Asthma Benzene Benzo(a)pyrene Biodegradation Biological Biomass Bioremediations Breathing Carcinogens Catalysis Cations Charge Chemicals Chronic Chrysenes Complex Development Electrons Environment Excision Exposure to Fossil Fuels Glycols Human Human Activities Investigation Isomerism Ketones Kinetics Life Link Mass Spectrum Analysis Measures Mediating Methods Modeling Mutagens Parents Particulate Matter Pathway interactions Phase Procedures Process Public Health Pyrenes Quinones Relative (related person)Research Role Scientist Site Solutions Structure Surface System Techniques Toxic effect Water Work analytical tool aqueous autooxidation charge transfer complex cost effective design electron donor flexibility fluoranthene minimally invasive particle photolysis physical property pollutant quantum remediation respiratory success sunlight-induced tool

项目摘要

DESCRIPTION (provided by applicant): Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and mutanogenic pollutants ubiquitous in the natural world. Human activities, including the combustion of fossil fuels, contribute to the total abundance of these compounds in the environment. Semi-volatile PAHs adsorbed to fine particulate matter enter the body via inhalation. It is a matter of public health to understand the fate of PAHs after they are released into the environment. Sunlight-induced photooxidation is an important method of PAH removal from the environment. The proposed research is designed to measure photochemical rate constants and product quantum yields necessary to predict the rates of PAH decay in condensed phase systems including atmospheric particles, water, and other environmental surfaces. Unlike previous studies, the results of this study can be used to identify and quantify PAH photooxidation products in local environments. This is important information because PAH photooxidation products are not only more reactive than PAHs and another group of suspected carcinogens, but they are also more soluble in aqueous systems and consequently can be transported over longer distances. The hypothesis of the proposed work is that PAHs that degrade predominately via the radical-cation mediated mechanism will have degradation rates that are dependent on the electron-donor capacity of the media in which they reside, and there will be a diversity of under-characterized and previously unidentified photoproducts created in these processes. To explore this hypothesis, three specific objectives for the proposed research have been formulated: (1) Characterize photoproducts of PAH photodegradation using structurally sensitive HPLC/MS/MS techniques; (2) Measure formation rates and quantum yields of the observed photoproducts in solutions with varied polarity to elucidate the role of electron donors on the rates of PAH photodegradation in the environment; (3) Manipulate mechanism-specific intermediates during photolysis to elucidate the dominant mechanism for PAH photodegradation in matrices with a range of electron-scavenging potentials. The proposed work will use recently developed LC/MS/MS techniques to measure the product quantum yields of PAH photooxidation in solutions with exceptional sensitivity and selectivity relative to other analytical techniques. The success of this project will help to elucidate the role of the environment on the damaging effects of particle inhalation. The study will also provide kinetic parameters necessary to model the photodegradation of environmental PAHs, inspiring ideas for removal from contaminated sites.

描述（由申请人提供）：多环芳烃（PAH）是自然界中普遍存在的致癌和致突变污染物。人类活动，包括化石燃料的燃烧，导致了环境中这些化合物的总丰度。半挥发性多环芳烃吸附在细颗粒物上，通过吸入进入体内。了解多环芳烃释放到环境中后的命运是一个公共卫生问题。阳光诱导的光氧化是去除环境中多环芳烃的重要方法。拟议的研究旨在测量光化学速率常数和产物量子产率，以预测凝相系统（包括大气颗粒、水和其他环境表面）中多环芳烃的衰变速率。与之前的研究不同，这项研究的结果可用于识别和量化当地环境中的 PAH 光氧化产物。这是重要的信息，因为多环芳烃光氧化产物不仅比多环芳烃和另一组可疑致癌物更具反应性，而且在水系统中更易溶解，因此可以传输更远的距离。拟议工作的假设是，主要通过自由基阳离子介导机制降解的 PAH 的降解速率取决于它们所在介质的电子供体能力，并且将存在多种未充分表征的物质。以及在这些过程中创建的先前未识别的照片产品。为了探索这一假设，本研究制定了三个具体目标：（1）使用结构敏感的 HPLC/MS/MS 技术表征 PAH 光降解的光产物； (2) 测量不同极性溶液中所观察到的光产物的形成速率和量子产率，以阐明电子供体对环境中 PAH 光降解速率的作用； (3) 操纵光解过程中特定机制的中间体，以阐明具有一系列电子清除电位的基质中 PAH 光降解的主要机制。拟议的工作将使用最近开发的 LC/MS/MS 技术来测量溶液中 PAH 光氧化的产物量子产率，相对于其他分析技术具有优异的灵敏度和选择性。该项目的成功将有助于阐明环境对颗粒吸入破坏性影响的作用。该研究还将提供模拟环境多环芳烃光降解所需的动力学参数，激发从污染场地去除的想法。