Abstract：
Supercritical water gasification technology provides a favorable technology to achieve pollution elimination and resource utilization of phenolic wastewater. In this study, the reaction mechanism of phenolic wastewater supercritical water gasification was investigated using a combination of experimental and computational methods. Five reaction channels were identified to elucidate the underlying pathway of phenol decomposition. Importantly, the rate-determining step was found to be the dearomatization reaction. By integrating computational and experimental analyses, it was found that phenol decomposition via the path with the lowest energy barrier generates cyclopentadiene, featuring a dearomatization barrier of 70.97 kcal/mol. Additionally, supercritical water plays a catalytic role in the dearomatization process by facilitating proton transfer. Based on the obtained reaction pathway, alkali salts (Na2CO3 and K2CO3) are employed as a catalyst to diminish the energy barrier of the rate-determining step to 40.00 kcal/mol and 37.14 kcal/mol. Alkali salts catalysis significantly improved carbon conversion and pollutant removal from phenolic wastewater, increasing CGE from 58.44% to 93.55% and COD removal efficiency from 94.11% to 99.79%. Overall, this study provides a comprehensive understanding of the decomposition mechanism of phenolic wastewater in supercritical water.
摘要：
超临界水气化技术为实现含酚废水的污染消除和资源化利用提供了有利的技术。在这项研究中,采用实验和计算相结合的方法研究了含酚废水超临界水气化的反应机理。确定了五个反应通道以阐明苯酚分解的潜在途径。重要的是,发现速率决定步骤是脱芳构化反应。通过整合计算和实验分析，发现苯酚通过具有最低能垒的路径分解产生环戊二烯，具有70.97kcal/mol的脱芳烃屏障。此外,超临界水通过促进质子转移在脱芳烃过程中起催化作用。根据获得的反应途径，使用碱金属盐（Na2CO3和K2CO3）作为催化剂，将速率确定步骤的能垒降低至40.00kcal/mol和37.14kcal/mol。碱金属盐催化显著提高了含酚废水的碳转化率和污染物去除，将CGE从58.44%提高到93.55%，COD去除率从94.11%提高到99.79%。总的来说,本研究为含酚废水在超临界水中的分解机理提供了全面的认识。
