Facile preparation of nano-Fe3O4/micro-carbon fiber from waste paper as self-propulsive solar-Fenton catalyst with excellent degradation performance and reusability

Magnetically recyclable and self-propulsive micron carbon fiber (CF) immobilizing Fe3O4nanoparticles with favorable solar-Fenton catalytic activity were successfully prepared by a combined twostep method. In the first step, CF was synthesized from waste paper and subsequently modified by mussel-inspired polydopamine (PDA) with biomimetic adhesion function and highly active functional groups. In the second, well-dispersed Fe3O4nanoparticles were fabricated and anchored on the surface of the PDA modified CF. The solar-Fenton catalytic performance and reusability for the composites were fully evaluated. The results show the degradation rate of the prepared catalyst for methylene blue (MB) in a free agitating process reached 97.8% after 80 min under simulated Sunlight. After 10 repetitive catalytic cycles, the degradation rate for MB could maintain above 95% meanwhile the magnetic properties of the catalyst remained strong indicating good recovery of the catalyst after the reaction. The possible degradation mechanism of MB is also discussed. It indicates that hydroxyl radicals play an important role in the catalytic degradation reaction, while hole trapping and superoxide radical are beneficial to the enhancement of decolorization efficiency of MB.