Sulfidation modified Fe3O4 nanoparticles as an efficient Fenton-like catalyst for azo dyes degradation at wide pH range

The application of a novel sulfidation modified Fe 3 O 4 nanoparticles (S-Fe 3 O 4 NP) as catalyst for degradation of dyes-containing wastewater through Fenton-like reaction is investigated in the current research. Results demonstrate the as-prepared S-Fe 3 O 4 NP is mainly composed of interconnected FeS 2 and sulfur-doped Fe 3 O 4 , which can be recovered from aqueous solution by magnetic separation method. S-Fe 3 O 4 NP/H 2 O 2 catalytic system exhibits great advantage and much higher catalytic performance over Fe 3 O 4 based Fenton-like process, which can effectively degrade RhB at wide pH range from 3 to 9. It also presents excellent recyclability in the first three cycles and high catalytic activity towards degradation of various azo dyes such as MB , MG and AR-73. The H + species, Fe 2+ ions and surface Fe 2+ active sites generated in the S-Fe 3 O 4 NP/H 2 O 2 system can significantly facilitate the production of hydroxyl radicals and this synergetic effect between FeS 2 and sulfur-doped Fe 3 O 4 leads to the enhanced catalytic performance of S-Fe 3 O 4 NP.