Co/Bi催化剂催化湿法氧化降解垃圾渗滤液中的氨氮

Catalytic Wet Air Oxidation of Ammonia in Landfill Leachates in the Presence of Co/Bi Catalyst

采用催化湿法氧化 (CWAO)技术 ,以 Co/ Bi为催化剂 ,对垃圾渗滤液中氨氮 (NH3-N)进行降解处理 ,并利用 GC-MS检测了垃圾渗滤液中含氮有机物的相对含量 .结果表明 ,随着反应温度的升高 ,CWAO对NH3-N的降解能力逐渐增强 ,在 2 2 0 ,2 40 ,2 60和 2 80℃条件下 ,NH3-N降解规律符合一级动力学反应 (r>0 .93 ,n=6) .在升温过程 (2 0～ 3 0 0℃ )中 ,NH3-N浓度变化经历了先升后降两个阶段 ,并在 2 2 0℃时达到最大值 .GC-MS检测结果表明 ,在第一阶段 ,垃圾渗滤液中几种含氮有机物因催化氧化而生成 NH3-N;第二阶段 ,NH3-N逐渐被氧化降解 ,达到了 CWAO技术同时降解有机物和 NH3-N的目的 .同时 ,选取垃圾渗滤液中一种含氮有机物 2 -巯基苯并噻唑进行含氮有机物氮降解机理的验证实验 .

Catalytic Wet Air Oxidation(CWAO) was used for the decomposition of ammonia(NH_3-N) from the landfill leachates in the presence of Co/Bi catalyst and the relative content of nitrogenous organic compounds in the landfill leachates was also measured by GC-MS. The results show that the decomposition ability of NH_3-N by CWAO gradually increased with increasing reaction temperature. The kinetic decomposition of NH_3-N at temperatures 220, 240, 260 and 280 ℃ was well described with the first-order kinetics model(r>0.93, n=6). During the overall process of temperature rising(20—300 ℃), the concentration of NH_3-N increased in the first stage and then decreased in the second stage, which culminated at 220 ℃. Further investigations by GC-MS indicated that during the first stage, some nitrogenous organic compounds in the landfill leachates were degraded into NH_3-N by CWAO, and then NH_3-N was degraded by CWAO during the second stage, which presented the advantage of simultaneous removal of both NH_3-N and organic compounds by CWAO. One of the nitrogen-organic compounds, 2-mercaptobenzothiazole, in the landfill leachates was selected to verify the degradation of the nitrogen-organic compounds.