A novel route for microplastic mineralization: visible-light-driven heterogeneous photocatalysis and photothermal Fenton-like reaction

Microplastic pollution has attracted considerable attention. Here, we develop a visible-light-driven photocatalysis and photothermal Fenton-like reaction method for their removal, utilizing an alpha-Fe2O3 nanoflower on TiO2 with a hierarchical structure of inverse opal-like layer/nanotube arrays (alpha-Fe2O3/TiO2HNTAs film). Without external H2O2 dosage, nearly 100% degradation of 310 nm polystyrene (PS) spheres is obtained after 4 h at 75 degrees C induced by visible-light irradiation. The light initiation and photothermal effect are essential for achieving high degradation efficiency of plastics on alpha-Fe2O3. A distinctive melting phenomenon of PS under mild conditions due to the synergistic effect is observed for the first time. The catalyst system also works well for PS spheres with large particle size (2.0-2.9 mu m) and real PS plastic foam. We believe that this work provides a novel strategy and new insights for removing microplastics and bulk plastics. A synergic mode of heterogeneous photocatalysis and photothermal Fenton-like reaction for highly efficient microplastic degradation, utilizing alpha-Fe2O3 nanoflower on TiO2 with a hierarchical structure of inverse opal-like layer/nanotube arrays.

Automated summary

In this study, a visible-light-driven photocatalysis and photothermal Fenton-like reaction method for the removal of microplastics is developed by utilizing alpha-Fe2O3 nanoflower on TiO2 with a hierarchical structure of inverse opal-like layer/nanotube arrays. The results show that the light initiation and photothermal effect are essential for achieving high degradation efficiency of plastics, and a distinctive melting phenomenon of plastics under mild conditions is observed for the first time. The catalyst system also demonstrates good performance in degrading plastic spheres and foam of different particle sizes. This work provides a novel strategy and insights for removing microplastics and bulk plastics.