Yan Xiuxiu, An Jing, Zhang Yanzi, Wei Shuhe, He Wenxiang, Zhou Qixing
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; National-Local Joint Engineering Laboratory of Contaminated Soil Remediation by Bio-physicochemical Synergistic Process, Shenyang 110142, China.
J Hazard Mater. 2023 Oct 15;460:132259. doi: 10.1016/j.jhazmat.2023.132259. Epub 2023 Aug 19.
Photodegradation process plays an important role in the natural attenuation of petroleum hydrocarbons (PHs) in oil contaminated soil. The photodegradation characteristics of PHs (C-C) in topsoil of crude oil contaminated soil irradiated by simulated sunlight in 280 d without microbial action were investigated. The results showed that photodegradation rate of PHs was increased with increasing the light intensity and decreased with increasing the initial concentration of PHs. Moreover, the photodegradation capacity of tested PHs was relevant to the length of carbon chain. The photodegradation rates of C-C were higher than that of C-C in photoperiod. C-C showed an obvious trend of photodegradation after 56 d, although their photodegradation rates were less than 20% at the early stage. And, the redundancy analysis indicated that lighting time was the primary factor for photodegradation of PHs under abiotic conditions. The photodegradation rate was well interpreted by a two-stage, first-order kinetic law with a faster initial photolysis rate. The EPR spectrums showed that simulated solar irradiation accelerated the generation of superoxide radicals, which could react with PHs in soil. Also, the function groups in PHs polluted soil were changed after light exposure, which might imply the possible photodegradation pathway of PHs.
光降解过程在石油污染土壤中石油烃（PHs）的自然衰减中起着重要作用。研究了在无微生物作用的情况下，模拟阳光照射280天原油污染土壤表土中PHs（C-C）的光降解特性。结果表明，PHs的光降解速率随光照强度的增加而增加，随PHs初始浓度的增加而降低。此外，受试PHs的光降解能力与碳链长度有关。在光周期内，C-C的光降解速率高于C-C。C-C在56天后呈现出明显的光降解趋势，尽管其在早期的光降解速率小于20%。而且，冗余分析表明，光照时间是在非生物条件下PHs光降解的主要因素。光降解速率可以用具有较快初始光解速率的两阶段一级动力学定律很好地解释。电子顺磁共振光谱表明，模拟太阳辐射加速了超氧自由基的产生，超氧自由基可与土壤中的PHs发生反应。此外，光照后PHs污染土壤中的官能团发生了变化，这可能暗示了PHs可能的光降解途径。
