燃烧及碳纳米材料的生产和处置过程中，均有可能产生富勒烯（ C60）等纳米颗粒物．这些纳米颗粒物进入大气后，主要存在于气溶胶中．由于本身的共轭结构C60可以吸收紫外可见光发生光氧化转化，研究C60在气溶胶中的光转化对于评价其环境归趋具有重要意义．本研究以环己烷、甲苯和二氯甲烷等溶剂模拟气溶胶表面液体层，采用模拟日光实验和密度泛函理论（ DFT）计算研究了C60在3种溶剂中的光化学转化．实验结果表明，C60在环己烷、甲苯和二氯甲烷中的光降解符合准一级动力学，光解速率常数分别为（0．80±0．01）×10－3、（3．80±0．02）×10－3、（14．80±0．20）×10－3 min－1．DFT计算结果表明，C60在3种溶剂中均可以通过光致产生1O2发生氧化反应．然而，仅在二氯甲烷中C60可以通过电子转移生成O·－2来促进C60的光转化．甲苯溶剂中激发态甲苯分子可以敏化C60产生C·－60从而加快C60的降解．理论计算结果有助于解释实验中C60在二氯甲烷中光解速率最快，在甲苯中光解速率比在环己烷中快的现象．
Fullerene ( C60 ) nanoparticles can be produced during combustion, carbonaceous nanomaterials production and disposition. These nanoparticles mainly exist in aerosols when released to the atmosphere. Photo?oxidation is an important degradation process for C60 because of its conjugated structure and strong light?absorbing properties within the solar spectrum. Phototransformation of C60 in aerosols has important implications for its environmental fate. Herein, we performed simulated sunlight experiments and density functional theory ( DFT ) computations to investigate photochemical transformation of C60 in three solvents, cyclohexane, toluene and dichloromethane that were selected as model aerosol surface. The experimental results show that phototransformation of C60 in these organic phases can be described by first order kinetics, and the photodegradation rate constants of C60 in cyclohexane, toluene and dichloromethane were ( 0. 80 ±
0.01) × 10-3 , ( 3. 80 ± 0. 02 ) × 10-3 , ( 14. 80 ± 0. 20 ) × 10-3 min-1 , respectively. DFT calculation indicates 1 O2 can be photogenerated in the three solvents and participates in the photodegradation of C60. However, O·-2 can only be produced in dichloromethane through electron transfer from C60 to O2, and C·-60 can be formed in toluene as a result of electron transfer from T1Toluene? to C60. The DFT calculation results can explain why the photodegradation rate constant of C60 in these solvents decreased in the order of k dichloromethane> k toluene> k cyclohexane .
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