Li Guoxing, Niu Mingbo, Chen Yue
Shaanxi Key Laboratory of New Transportation Energy and Automotive Energy Saving, School of Energy and Electrical Engineering, Chang'an University, Xi'an, Shaanxi, 710064, PR China.
Shaanxi Key Laboratory of New Transportation Energy and Automotive Energy Saving, School of Energy and Electrical Engineering, Chang'an University, Xi'an, Shaanxi, 710064, PR China.
J Environ Manage. 2025 Jan;373:123992. doi: 10.1016/j.jenvman.2024.123992. Epub 2025 Jan 2.
Benzene and phenol are representative aromatic compounds existing commonly in wastewater. The kinetics of oxidative degradation of benzene and phenol in supercritical water have been investigated in a flow reactor at 823 K and 250 atm, with the excess oxygen ratio ranging from 0.5 to 2.0. For supercritical water oxidation of benzene, CO was observed as the main product accounting for the largest fraction of the reacted carbon. Its concentration was higher than that of CO under all conditions, even at the initial reaction periods where benzene conversions were low. The phenol conversion was found to accelerate with increasing excess oxygen ratio, exhibiting strong dependence on oxygen concentration. CO and CO were the major gaseous products with comparable concentrations, and CH was also formed in considerable amounts. A comprehensive chemical kinetic model was developed based on a gas-phase mechanism, and its performance was further validated by comparing to experimental data from different sources. The model reproduced the benzene and phenol conversions and CO concentration fairly well, but underpredicted the CO yield and overpredicted the CH2 yield slightly. Reaction mechanisms were then inferred through kinetic analyses, emphasizing the importance of CHOO and CHO radicals. Finally, the kinetic characteristics of benzene and phenol oxidation in supercritical water and gas-phase environments were compared.
苯和苯酚是废水中常见的代表性芳香族化合物。在流动反应器中，于823K和250个大气压下，研究了苯和苯酚在超临界水中的氧化降解动力学，过量氧气比范围为0.5至2.0。对于苯的超临界水氧化，观察到CO是主要产物，占反应碳的最大比例。在所有条件下，其浓度均高于CO，即使在苯转化率较低的初始反应阶段也是如此。发现苯酚转化率随着过量氧气比的增加而加速，对氧气浓度表现出强烈的依赖性。CO和CO是主要气态产物，浓度相当，并且还大量生成CH。基于气相机理建立了一个综合化学动力学模型，并通过与不同来源的实验数据进行比较进一步验证了其性能。该模型较好地再现了苯和苯酚的转化率以及CO浓度，但略微低估了CO产率并略微高估了CH2产率。然后通过动力学分析推断反应机理，强调了CHOO和CHO自由基的重要性。最后，比较了苯和苯酚在超临界水和气相环境中氧化的动力学特征。
