预磁化强化ZnO@Fe3O4活化PMS降解AO7

为了研究预磁化对ZnO@Fe_3O_4活化过一硫酸盐(PMS)去除水中酸性橙7(AO7)性能的影响,考察了预磁化强度、ZnO@Fe_3O_4投量、PMS投量及初始pH对Mag-ZnO@Fe_3O_4/PMS体系降解AO7效果的影响.结果表明,当预磁化强度由0 T逐渐增大至2 T时,催化剂去除AO7的表观速率常数由0.0463 min~(-1)逐渐增大至0.1832 min~(-1),反应速率提高倍数达到1.4～4.0倍; Mag-ZnO@Fe_3O_4和PMS投量的增加对AO7的去除率均有提升效果,在最优条件下反应20 min后AO7的去除率达92%;体系初始pH对AO7降解有显著影响, pH为6～8条件下有利于Mag-ZnO@Fe_3O_4催化PMS氧化反应的进行.通过投加不同种类的猝灭剂,证实了AO7的降解主要是各种自由基共同作用的结果.经过预磁化处理后的催化剂产生感应磁场,从而影响了反应体系中自由基的复合概率,使得污染物被自由基氧化的速率提高.

Pre-magnetization enhancement for the decolrization of acid orange 7 by ZnO@Fe3O4 activated peroxymonosulphate

In order to study the performance of pre-magnetization on Acid Orange 7 (AO7) removal by ZnO@Fe₃O₄/peroxymonosulphate (PMS), the effects of different intensity of external magnetic fields, ZnO@Fe₃O₄ dosages, PMS dosages and initial pH on the AO7 degradation were investigated. With the increasing of magnetic intensity for preparing pre-magnetized ZnO@Fe₃O₄ (Mag-ZnO@Fe₃O₄) from 0 to 2 T, the rate constant of Acid Orange 7 (AO7) degradation was enhanced progressively from 0.0463 to 0.1832 min^-1 and the corresponding enhancement factor was varied from 1.4 to 4.0. The experimental results indicated that high ZnO@Fe₃O₄ and PMS dosages had a positive impact on the degradation of AO7, and the degradation rate of AO7 could reach 92% under the optimal reaction condition. In addition, initial pH had a significant influence on the degradation of AO7, and initial pH 6~8 enhanced the degradation efficiency. By adding different radical scavengers, it is confirmed radicals play the key role in AO7 degradation. The pre-magnetion induced magnetic field influenced the recombination probability of radicals,promoted the consumption of radicals and the oxidation of pollutants.