采用实验和密度泛函理论计算揭示吸光性环境介质对多环芳烃光降解的影响机制  

Employing experiment and density functional theory calculation to unveil the effects of light-absorbing media on photodegradation of polycyclic aromatic hydrocarbons

作　　者：邵建平[1] 陈景文[1] 谢晴[1] 张思玉[1,2] 

机构地区：[1]工业生态与环境工程教育部重点实验室,大连理工大学环境学院,大连116024 [2]环境模拟与污染控制国家重点联合实验室,清华大学环境学院持久性有机污染物研究中心,北京100084

出　　处：《环境化学》2013年第7期1246-1252,共7页Environmental Chemistry

基　　金：国家重点基础研究计划(973)课题(2013CB430403);国家自然科学重点基金(21137001)资助

摘　　要：多环芳烃(PAHs)在环境中的光降解动力学受环境介质吸光组分的影响.为揭示介质吸光组分对PAHs光降解影响的内在机制,以吸光很弱的甲醇和吸光较强的丙酮和二甲基亚砜(DMSO)为模拟环境介质,考察不同吸光性溶剂介质对3种PAHs(菲、芘和苯并[a]芘)光解的影响;并采用密度泛函理论(DFT)计算,分析了溶剂分子光敏化能量/电子转移反应对PAHs光解的影响机制.结果表明,激发态的丙酮分子抑制了菲和芘的光解,而加快了苯并[a]芘的光解;激发态的DMSO分子抑制了菲的光解,促进了芘和苯并[a]芘的光解.过滤掉DMSO所吸收的部分光谱频段后,PAHs在DMSO中的光解速率与甲醇中的接近.DFT计算表明,激发态的丙酮或DMSO主要作为电子受体与PAHs发生光敏化电子转移反应,是影响PAHs光解的内在原因.Photodegradation kinetics of polycyclic aromatic hydrocarbons （PAHs） strongly depends on the effects of light-absorbing constituents of the environmental media. In order to unveil the effects of the light-absorbing constituents on the photodegradation of PAHs, three solvents （ methanol, acetone and dimethylsulfoxide） were selected to model the light-absorbing constituents of environmental media, and were employed in a simulated photodegradation experiment solvents, methanol has very strong PAHs sunlight absorbance. were analyzed with th acetone photode for three PAHs （phenanthrene, pyrene and benzo[ a ] pyrene）. Among the three weak sunlight absorbance, while acetone and dimethylsulfoxide （DMSO） have The photoindueed electron/energy transfer reactions between the solvents and e aid of density functional theory （DFY） calculation. The results indicated that significantly inhibited the photodegradation rate of phenanthrene and pyrene, but enhanced the gradation of benzo [ a] pyrene. DMSO significantly inhibited the photodegradation rate of phenanthrene, but enhanced the photodegradation of pyrene DMSO, the photodegradation rate constants of and benzo[ a] pyrene. After filtering out the light-absorption of the three PAHs in DMSO were similar to those in methanol. The computational results indicated that the electron transfer from PAHs to the excited state acetone （ or DMSO） is the main reason which influenced the PAHs photodegradation.

关 键 词：多环芳烃 光解 吸光性介质 DFT计算 

分 类 号：X50[环境科学与工程—环境工程]