Heterogeneous Fenton system with dual working mechanisms for aqueous pollutants degradation

Fenton reaction is an efficient method for advanced oxidation in water treatment. Improving the efficiency of the rate-limiting step in Fenton reaction system is highly desirable. However, the distinct degradation mechanisms towards different pollutants in the same Fenton or Fenton-like system are sometimes overlooked. In this contribution, introduction of a suitable co-catalyst into Fenton reaction system was proposed and the corresponding degradation mechanism was studied. Herein, as an efficient co-catalyst, MoS2 was assembled with a Fe-based mixed-valence metal-organic framework (MOF) matrix (NH2-MIL-101 (Fe)) to form peony-like hetero-architecture composite materials through a facile hydrothermal method. The prepared composites showed excellent performance in removing 97.4% Rhodamine B (50 ppm) and 99.9% bisphenol A (20 ppm) within 10 min. Moreover, the different degradation mechanisms for bisphenol A (co-catalyst accelerated Fenton reaction) and Rhodamine B (pollutant photosensitization assisted degradation) were elucidated by X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy and radical scavenging experiments. This co-catalyst cooperative Fenton system design strategy and distinct degradation mechanisms would be helpful for developing high-performance Fenton reaction systems.