Fe3O4/CeO2复合材料催化降解橙黄G的效能及降解途径

为研究磁性纳米Fe₃O₄/CeO₂复合材料在高浓度难降解有机废水处理中的应用，利用共沉淀法制备Fe₃O₄/CeO₂复合材料，并将其作为非均相类Fenton催化剂降解橙黄G染料废水，利用单因素法优化出最佳降解工艺，同时利用TOF-MS/MS(飞行时间质谱)检测降解中间产物，推测出可能降解途径.结果表明，当Ce/Fe为1 :1(质量比)时制备的Fe₃O₄/CeO₂复合材料催化效果最佳.最佳降解工艺条件:初始pH为2.0，温度为30 ℃，H₂O₂投加量为30 mmol/L，Fe₃O₄/CeO₂复合材料的投加量为2.0 g/L，初始ρ(橙黄G)为50 mg/L.在最佳降解工艺条件下反应120 min后，橙黄G去除率为96.2%，TOC去除率为65.0%，Fe₃O₄/CeO₂复合材料至少可重复利用6次.研究显示，橙黄G降解主要有三条可能的降解途径，包括偶氮键断裂、偶氮键与苯环断开、脱磺酸基、羟基化以及开环等过程，共检测出八种可能的降解中间产物，主要有苯胺、苯酚、萘酚以及羧酸等. 

OG Degradation Efficiency and Pathway Using Fe3O4/CeO2 Composite

Abstract: In recent years, environmental pollution has become more and more serious. High concentration refractory organic wastewater is highly toxic and difficult to decompose. Therefore, developing a new high efficient wastewater treatment process is extremely urgent. Fe₃O₄/CeO₂ composite was synthesized using the co-precipitation method. The composite was used for the degradation of Orange G as Fenton-like heterogeneous catalyst. The process parameters were investigated by the single factor experiment. The degradation intermediate products were determined by TOF-MS/MS. The possible degradation pathway of OG by heterogeneous Fenton-like process was attained. The results indicated that the optimal conditions were pH value 2.0, H₂O₂ concentration 30 mmol/L, initial dye concentration 50 mg/L, catalyst dosage 2.0 g/L and temperature 30 °C. Under the optimal conditions, the degradation percentage of OG was 96.2% within 120 min, and the TOC removal rate was 65.0%. Mass spectrometry analysis results showed that the OG degradation was mainly through three possible degradation pathways, including the process of azo bond rupture, desulfonation, hydroxylation and ring opening process. Eight possible degradation intermediate productions were measured, including aniline, phenol, naphthol and carboxylic acid.