用超临界水氧化技术降解废水中的TNT

Degradation of TNT by Supercritical Water Oxidation

利用超临界水氧化(SCW O)实验装置,研究了不同工艺条件下超临界水氧化技术对废水中TNT的降解规律。结果表明,采用超临界水氧化技术可以有效去除废水中的TNT。反应温度、停留时间是影响TNT降解效果的主要因素,随着反应温度、停留时间的增加,TNT的降解率显著增大。在反应温度为550℃、压力24 M Pa、反应时间120 s的条件下,废水中TNT的降解率可以达到99.9%。通过色谱-质谱(GC-MS)联用对超临界水氧化降解TNT的中间产物进行了分析。结果表明,中间产物主要有三硝基苯、甲苯、硝基苯酚、萘、芴、菲、蒽、邻苯二甲酸正丁酯和庚烷、十二烷、十四烷等直链饱和烷烃,证实SCWO降解TNT的同时,发生了偶合、水解、异构化等副反应。探讨了TNT在超临界水中的氧化反应机理。

The supercritical water oxidation （SCWO） experimental facility was used to investigate the degradation rules of TNT in waste water under different technology conditions. The results show that SCWO technology can eliminate TNT in waste water effectively. Temperature and residence time are two principal factors affecting TNT degradation efficiency. On the supercritical condition, TNT degradation efficiency improved obviously as reaction temperature and residence time rising. A degradation efficiency of 99. 9% in TNT waste water can be obtained under the conditions of 550℃, 24 MPa and 120 s. The degradation intermediate products were analyzed by GC- MS. The results show that the main intermediates during SCWO included 1, 3, 5-trinitrobenzene, toluene, nitrophenol, naphthalene, fluorine phenanthrene, anthracene, dibutyl phthalate, heptane, dodecane, tetradecane and other linear chain paraffins, confirming that many side reactions, such as coupled reaction, hydrolysis reaction and isomerization reaction happened simultaneously as TNT is oxidized by SCWO. The degradation mechanism of TNT in supercritical water is discussed.