Reutilization of iron sludge as heterogeneous Fenton catalyst for the degradation of rhodamine B: Role of sulfur and mesoporous structure.

Fenton process has gained considerable interest for its application in water treatment. However, the removal of iron sludge which generated during the process makes this method complex and uneconomical. In this study, we report a novel way of modifying iron sludge and use it as heterogeneous Fenton catalyst for the degradation of dye wastewater. It was found that after calcination at 600 °C, the iron sludge (Fe-600) exhibited much enhanced catalytic performance (99%) toward rhodamine B (RhB) in comparison with iron sludge without calcination (10%) in the presence of H2O2. The mesoporous structure of Fe-600 could facilitate its adsorption and immobilization of RhB, and the self-doped lattice sulfide played an important role during the Fenton degradation process. Moreover, the Fe-600 exhibited excellent heterogeneous Fenton degradation efficiency of acid red G and methylene blue as well. Our results may shed new light on the scalable preparation of novel heterogeneous Fenton catalysts and make contribution to the application of homogeneous Fenton degradation of wastewater.