Magnetically recyclable flake-like BiOI-Fe3O4 microswimmers for fast and efficient degradation of microplastics

Abstract

Microplastics ubiquitously in the environment endanger both marine organisms and human beings. Currently, the smaller sizes of microplastics in size ranging from 1 µm to 10 µm are likely to pass through the filtration systems in water treatment facilities and present in the drinking water supply. This study proposes a promising method of degrading the 1.1 µm polystyrene latex (PSL) beads microplastics using a self-propelled and magnetically recovered BiOI-Fe3O4 microswimmer. The results reveal flake-like BiOI-Fe3O4 microswimmer successfully degrades 64% polystyrene microplastics in 120 h and reduces the concentration of microplastics in an aqueous solution from 0.05 g/L to 0.018 g/L. The presence of visible light and H2O2 fuel induced the movement of the microswimmer by the decomposition of H2O2 into oxygen bubbles. It is observed that the microswimmer with the mean particle size of 3.913 µm can move at a reasonable speed of 3.0498 µm/s in 5 wt% H2O2 concentration under 3.6 W visible light irradiation. It can be concluded that PSL degrades rapidly when exposed to visible light for less than 24 h.