Removal and Degradation of Microplastics Using the Magnetic and Nanozyme Activities of Bare Iron Oxide Nanoaggregates

Removal and degradation of microplastics are often carried out separately. In this work, hydrophilic bare Fe3O4 nanoaggregates allowed efficient removal of the most common microplastics including high-density polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyethylene terephthalate. Full extraction was achieved using Fe3O4 at 1 % of the mass of microplastics. Hydrogen bonding is the main force for the adsorption of Fe3O4. Unlike the more commonly used hydrophobically modified Fe3O4 nanoparticles, the bare Fe3O4 benefitted from the peroxidase-like activity of its exposed surface, enabling further catalytic degradation of microplastics with nearly 100 % efficiency and easy recovery of the Fe3O4.