Abstract
In this work, Hangjin2(#) clay (HC), a natural iron-contained clay mineral first discovered in Inner Mongolia of China, is found to be able to catalyze the heterogeneous Fenton reaction efficiently upon rational modification. After activation using dilute sulfuric acid, the HC prohibited a significantly enhanced activity for heterogeneous Fenton reaction. Via acid activation process, Fe2+/Fe3+ redox can be introduced on the surface of sulfuric acid-activated Hangjin2(#) clay (SHC), and Bronsted acid sites can be also created on the surface of SHC. Furthermore, Bronsted acid sites could effectively promote the generation of center dot OH for methyl orange (MO) oxidation and facilitate the Fe3+/Fe2+ redox process. Fenton degradation of MO was used to evaluate the effect of acid activation on the catalytic activities of SHC. Experimental results revealed that the high activity of SHC was mainly attributed to the synergetic effect of the abundant acid sites on catalyst surface and the Fe3+/Fe2+ redox process. In addition, quenching studies confirmed that center dot OH radicals were principally responsible for the degradation of MO. More importantly, MO degradation for 3 consecutive cycles demonstrated SHC exhibited reusable and stable activity.