基于同位素标记的典型VOCs同分异构体太阳光催化降解机理研究

In order to effectively understand and simulate the photodegradation transformation process and mechanism of typical volatile organic compounds (VOCs) in the atmospheric environment, two kinds of VOCs isomers with position and functional group isomerism are selected as target compounds. Firstly, the adsorption as well as degradation performances and mechanisms of these isomers with their similarities and differences are discussed by using in-situ infrared system, proton transfer reaction-time of flight mass spectrometry, nuclear magnetic resonance apparatus, etc. Meanwhile, the corresponding relationship between adsorption characteristic and degradation behavior is established. Furthermore, according to isotope labeling the oxygen atom of O2 and H2O reaction species in the system as well as carbon atom of VOCs isomers, the reaction sites of VOCs isomer are clarified, while the fate of reaction species as well as their reaction mechanism with the typical functional groups of VOCs isomers are further revealed. In addition, the transformation process and fate of key atom on the VOCs isomers are explored. The top-down solar-light-driven photocatalytic degradation pathway and mechanism of the VOCs isomers are finally elaborated, while the answers for the similarities and differences of degradation mechanisms to VOCs isomers are solidly given. All these could provide detailed theoretical and experimental evidence for the photochemical migration, transformation and fate of typical VOCs, especially for VOCs isomers.

为了有效地了解和模拟研究大气环境中典型挥发性有机物(VOCs)的光化学转化过程和机制，本项目选取官能团位置异构和官能团异类异构的两类典型VOCs同分异构体为目标化合物，利用原位红外、质子传递反应飞行时间质谱和核磁共振等技术探讨VOCs同分异构体在光催化剂上吸附、降解行为和机理及其异同点，阐述VOCs同分异构体吸附特征与光催化降解行为之间的关系，进一步借助同位素标记示踪大气反应体系中反应物种(如O2和H2O)上O原子和VOCs同分异构体上特征原子(如C)，明晰VOCs同分异构体的光催化降解反应位点，揭示反应物种的归趋及其对VOCs同分异构体上特征官能团的作用机制，探究VOCs同分异构体上关键原子的光催化降解转化途径和归趋，揭示VOCs同分异构体自上而下的太阳光催化降解机理并阐释其异同的本质原因，为大气环境中典型VOCs特别是VOCs同分异构体的光化学迁移、转化和归趋提供详细的理论和实验依据。

为了有效地了解和模拟研究大气环境中典型挥发性有机物(VOCs)的光化学转化过程和机制，本项目选取官能团位置异构和官能团异类异构的两类典型VOCs同分异构体为目标化合物，主要开展了正己烷、丙烯醇、苯乙烯、二甲苯等一系列典型VOCs在TiO2、铋氧化物和复合金属氧化物等上的光催化降解过程和机理研究，并进一步结合氧同位素示踪技术，系统阐释了苯乙烯、二甲苯、甲苯、三甲苯等一系列典型VOCs太阳光催化降解过程中O2和H2O的贡献机制，为大气环境中典型VOCs特别是VOCs同分异构体的光化学迁移、转化和归趋提供详细的理论和实验依据。项目执行期间共发表标注SCI论文11篇，申请中国发明专利5件（已授权3件），培养硕士研究生5名，圆满地完成了预期目标。