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 (NaCO and KCO) 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.

中文翻译：

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含酚废水超临界水气化的机理见解和催化增强：实验与密度泛函理论相结合的研究

超临界水气化技术为含酚废水的污染消除和资源化利用提供了有利的技术。本研究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来阐明苯酚分解的潜在途径。重要的是，发现限速步骤是脱芳构化反应。通过综合计算和实验分析，发现苯酚沿着能垒最低的路径分解生成环戊二烯，其脱芳构化能垒为70.97 kcal/mol。此外，超临界水通过促进质子转移在脱芳构化过程中发挥催化作用。根据所获得的反应路径，采用碱金属盐（NaCO和KCO）作为催化剂，将限速步骤的能垒降低至40.00 kcal/mol和37.14 kcal/mol。碱盐催化显着提高了含酚废水的碳转化率和污染物去除率，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，这项研究提供了对超临界水中酚类废水分解机理的全面了解。