The optimization and mechanism for oxidation of the waste anion exchange resin from the nuclear industry in supercritical water were investigated. To achieve the maximum chemical oxygen demand (COD) and total nitrogen (TN) removal efficiencies, the response surface methodology (RSM) was employed to optimize four operating variables. Two quadratic polynomial models with satisfactory accuracy were established based on the experimental results. Under optimized conditions, the removal rates of the COD and TN could reach 99.91 and 36.02%, respectively. According to the identification of intermediates under different reaction conditions, a detailed degradation mechanism involving Huffman decomposition, depolymerization, oxidation, ring-opening, recombination, and finally oxidation to small molecules was proposed. As the quaternary ammonium falls off, the reaction mainly follows two routes. Phenols and amides were the main intermediates. The optimization and mechanism analysis would provide the theoretical basis and guidelines for the applications of supercritical water oxidation technology in the minimization and inorganic stabilization of radioactive waste.

中文翻译：

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超临界水中核工业模拟废离子交换树脂破坏的优化及机理研究

研究了核工业废阴离子交换树脂在超临界水中的氧化工艺及其机理。为了获得最大的化学需氧量（COD）和总氮（TN）去除效率，采用了响应面方法（RSM）来优化四个操作变量。根据实验结果建立了两个精度令人满意的二次多项式模型。在最佳条件下，COD和TN的去除率分别可以达到99.91％和36.02％。根据不同反应条件下中间体的鉴定，提出了详细的降解机理，涉及霍夫曼分解，解聚，氧化，开环，重组，最后氧化成小分子。随着季铵盐的脱落，反应主要遵循两种途径。酚和酰胺是主要中间体。优化和机理分析将为超临界水氧化技术在放射性废物的最小化和无机稳定化中的应用提供理论依据和指导。