A low-cost clay-based heterogeneous Fenton-like catalyst: Activation, efficiency enhancement, and mechanism study

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, Fe 2+ /Fe 3+ redox can be introduced on the surface of sulfuric acid-activated Hangjin2 # clay (SHC), and Brønsted acid sites can be also created on the surface of SHC. Furthermore, Brønsted acid sites could effectively promote the generation of •OH for methyl orange (MO) oxidation and facilitate the Fe 3+ /Fe 2+ 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 Fe 3+ /Fe 2+ redox process. In addition, quenching studies confirmed that •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.