CoFe_(2)O_(4)@Zeolite催化剂活化过一硫酸盐对甲基橙的强化降解:性能与机理

Enhanced Degradation of Methyl Orange with CoFe_(2)O_(4)@Zeolite Catalyst as Peroxymonosulfate Activator:Performance and Mechanism

采用共沉淀水热法制备了CoFe_(2)O_(4)@Zeolite(CFZ),并将其用于活化过一硫酸盐(PMS)降解合成染料。综合表征表明,组成多孔壳层的CoFe_(2)O_(4)纳米颗粒均匀地覆盖在Na-A沸石上。CFZ的比表面积为107.06 m^(2)/g,是原始沸石比表面积的3倍。CFZ的饱和磁化强度为29.0 A·m^(2)·kg^(–1),可以进行有效磁分离。催化降解实验表明,CFZ/PMS体系对甲基橙(MO)的去除率远远高于单独使用CFZ或PMS。在最佳条件([MO]=50 mg/L、[PMS]=1.0 mmol/L、0.2 g/L CFZ、pH 8和T=25℃)下,MO去除率可达到97.1%。实验研究了pH、PMS用量、CFZ用量、MO浓度以及共存阴离子等因素对CFZ催化性能的影响。活性氧粒子淬灭实验表明,1O2和O_(2)^(•–)在降解过程中起主导作用。CFZ具有良好的回收性能,5次循环后MO去除效率仅下降2.4%。本文还详细讨论了CFZ/PMS体系的催化降解机理。

CoFe_(2)O_(4)@zeolite(CFZ)was prepared by using a co-precipitation hydrothermal method and used for synthetic dyes degradation by activating peroxymonosulfate(PMS).Comprehensive characterizations suggest that CoFe_(2)O_(4)nanoparticles composing porous shell layer is uniformly covered on Na-A zeolite.The specific surface area of CFZ is 107.06 m2/g,three times that of the original zeolite.Since CFZ has a saturation magnetization of 29.0 A·m^(2)·kg^(–1),it could be separated efficiently by magnetic separation.Catalytic degradation experiments indicate that the removal of methyl orange(MO)in the CFZ/PMS system is much higher than that using CFZ or PMS alone.Under the optimum condition([MO]=50 mg/L,[PMS]=1.0 mmol/L,0.2 g/L CFZ,pH 8 and T=25℃),MO removal efficiency is up to 97.1%.Effect of various factors,including pH,PMS and CFZ dosage,MO concentration and presence of coexisting anions,on the catalytic performance of CFZ is carefully studied.Reactive oxygen species quenching experiments suggest that^(1)O_(2)and O_(2)^(•–)play a dominant role in the degradation process.CFZ shows excellent recycling performance that the MO removal is declined by only 2.4%after 5 cycles.Catalytic degradation mechanism of the CFZ/PMS system is explored in detail.