Synthesis of magnetically separable MnO2/Fe3O4/silica nanofiber composite with enhanced Fenton-like catalytic activity for degradation of Acid Red 73

For the first time, the hierarchical MnO2/Fe3O4/silica nanofiber (MnO2/Fe3O4/SNF) composite was successfully fabricated by immobilization of highly dispersed Fe3O4 nanoparticles and MnO2 nanosheets on the surface of chrysotile-based silica nanofiber through layer-by-layer assembly. In the composite, the silica nanofiber was served as backbone to inhibit the self-aggregation of nano-sized catalysts and maintain the stability of the overall structure. The as-synthesized composite was employed to catalyze the degradation process of Acid red 73 (AR-73) with the assistance of peroxymonosulfate (PMS). It was found that the composite exhibited an obvious enhancement in catalytic performance in comparison to the unsupported MnO2 and Fe3O4/MnO2 nanoparticles. Besides, the composite exhibited other advantages of easy separation and good recyclability. It was proposed that the excellent catalytic activity could be attributed to the high dispersion structure of the nano-catalyst in the composite. This research also exhibited the great potential of chrysotile-derived silica nanofiber as support material for the efficient assembly of nano-sized catalyst to apply in environmental remediation.