微波诱导Fe_2O_3/Al_2O_3催化剂催化氧化处理水中苯酚

Microwave-Induced Catalytic Oxidation Process for Treatment of Phenol in Water with Fe_2O_3/Al_2O_3 Catalyst

以γ-Al_2O_3为载体,采用浸渍焙烧法制备了Fe_2O_3/Al_2O_3催化剂,并将其应用于微波诱导催化氧化处理模拟含酚废水.X射线衍射和X射线荧光光谱测试结果表明,活性组分氧化铁在催化剂中以α-Fe_2O_3的形式存在,其含量为3.71%.与载体氧化铝相比,Fe_2O_3/Al_2O_3催化剂的比表面积和平均孔径及平均孔容略有降低.对于100mg/L的模拟含酚废水,最佳的处理工艺条件为微波辐照功率400W,辐照时间5min,催化剂加入量60g/L,H_2O_2浓度600mg/L,体系pH>4.在此工艺条件下,水中苯酚的去除率达97.98%.催化剂连续使用20次后苯酚去除率仍达96.34%.表观反应动力学研究表明,在氧化铁催化剂存在的条件下,微波诱导H2O2产生氧化性极强的羟基自由基,整个反应过程可分为微波诱导阶段和催化氧化阶段,两个阶段的氧化过程均符合一级反应动力学规律.

The ferric oxide catalyst was prepared by the dipping- calcination method using gamma-Al2O3 as a carrier and the microwave- induced oxidation process was developed to treat phenol in water. The catalyst structure was determined by XRD, XRF and N-2 adsorption. The effects of operating conditions on the catalyst activity, the using life of the catalyst and the reaction kinetics were studied. The results show that alpha-Fe2O3 is loaded on the surface of gamma-Al2O3 and the content of alpha-Fe2O3 in the catalyst is 3.71 %. Under the optimal treatment conditions of phenol concentration of 100 mg/L, microwave power of 400 W, irradiation time of 5 min, catalyst amount of 60 g/L, H2O2 concentration of 600 mg/L and pH > 4, a phenol removal rate of 97.98% is obtained. The catalyst can be reused more than 20 times remaining a phenol removal rate of 96. 34 %. The oxidation process can be divided into two stages, both of them are in accord with the first-order reaction kinetics.