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.
出处
《环境化学》
CAS
CSCD
北大核心
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
关键词
多环芳烃
光解
吸光性介质
DFT计算
polycyclic aromatic hydrocarbons, photodegradation, light-absorbing media, DFT prediction.
