Improvement of H2O2 Utilization by the Persistent Heterogeneous Fenton Reaction with the Fe3O4-Zeolite-Cyclodextrin Composite

Most previous reports related to heterogeneous Fenton focused on improving the catalytic activity of the catalysts but ignored the consumption and utilization efficiency of hydrogen peroxide (H2O2), which has caused a large invalid waste of H2O2. This paper reports a Fe3O4-zeolite-cyclodextrin (F-Z-C) heterogeneous Fenton catalyst that can prolong the reaction duration time and improve the H2O2 utilization. The pollutants can be adsorbed to the catalyst surface by the zeolite and the Fe3O4-cyclodextrin nanostructure, which will increase the local concentration of pollutants. Meanwhile, the H2O2 dispersed in water can be temporarily captured and stored by β-cyclodextrin, decreasing the invalid consumption of free H2O2. A series of experiments indicate that the F-Z-C catalyst can store H2O2 and release out slowly in a certain condition. Benefiting from the "storage-release" effect of F-Z-C on H2O2, the utilization efficiency of H2O2 can be greatly improved. As a result, the contradiction between the large needed amount and the low concentration of H2O2 can be solved in practical wastewater treatments.