湿式催化氧化降解焦化废水

Degradation of coking wastewater by the wet catalytic oxidation

摘要:

以Cu(NO3)2•3H2O为原料，采用共沉淀法制备了CuMgLa/Al2O3催化剂，TEM和N2吸脱附结果表明，该催化剂具有介孔结构，主活性组分CuO的粒径约为25 nm。以喹啉为降解目标污染物，考察了温度、催化剂质量浓度等对湿式催化氧化降解喹啉效果的影响。结果表明，当喹啉模拟废水质量浓度为1000 mg/L，催化剂质量浓度为0.2 g/L，反应温度为240 ℃，氧分压为0.53 MPa，反应60 min时，喹啉降解率接近100.0%，化学需氧量（COD）去除率达到94.8%。通过UV-Vis、LC-MS分析喹啉降解生成的中间体，结合叔丁醇淬灭实验，发现·OH氧化在湿式催化氧化降解喹啉体系中起主导作用，推测了喹啉可能的降解路径。在最优工艺条件下，COD质量浓度为7000 mg/L的模拟焦化废水COD的去除率达94.6%；而COD质量浓度为4740 mg/L，NH3-N质量浓度为884.2 mg/L的实际焦化废水COD去除率为69.6%，NH3-N去除率为28.0%。

Abstract:

CuMgLa/Al2O3 was prepared from Cu(NO3)2•3H2O by coprecipitation method and characterized by TEM and N2 adsorption-desorption technique. The results showed that CuMgLa/Al2O3 had a mesoporous structure and the particle size of the main active component CuO was about 25 nm. The effects of temperature and catalyst mass concentration on the degradation of quinoline by wet catalytic oxidation were investigated. It was found that under the conditions of mass concentration of quinoline simulated wastewater 1000 mg/L, catalyst mass concentration 0.2 g/L, reaction temperature 240 °C, oxygen partial pressure 0.53 MPa, reaction time 60 min, the removal rate of quinoline could reach about 100.0%, and the removal rate of chemical oxygen demand（COD）could reach 94.8%. The quenching experiments of tert-butanol revealed that ·OH oxidation played a key role in quinoline degradation. The intermediate of quinoline degradation was analyzed by LC-MS and UV-Vis, and the possible degradation path of quinoline was speculated. Meanwhile, under the optimal conditions, COD removal rate of 7000 mg/L mass concentration of simulated coking wastewater could reach 94.6%. The removal rates of COD and NH3-N were 69.6% and 28.0% for the actual coking wastewater with COD and NH3-N mass concentration of 4740 and of 884.2 mg/L.