Microplastic Remediation in Aqueous Systems via TiSiO4–Fe3O4 Microbots

Microplastics pose a significant threat to aquatic ecosystems and public health, necessitating efficient removal strategies. Current filtration-based water treatment methods, such as distillation, are energy-intensive and expensive. In this study, we utilized photocatalytic microswimmers, a type of self-propelling microbot that moves through liquid when exposed to light—a technology originally developed for microscale drug delivery. Varying concentrations of a TiSiO4–Fe3O4 microswimmer composite that we designed were introduced into solutions containing either polystyrene or polyethylene microplastics, hydrogen peroxide, and a buffer. The solutions were irradiated with white light, and absorbance was measured via UV-Vis spectroscopy at 0, 24, 96, and 144 hours following microswimmer introduction to assess microplastic degradation. Statistical analysis using Mann-Whitney U tests partially supported our hypothesis, showing a significant increase in degradation efficiency for polystyrene (P < 0.01) but not polyethylene (P = 0.20) as microswimmer concentration increased. In addition, microplastic degradation rates differed significantly between plastic types (P = 0.01). These findings highlight the promise of microswimmers for polystyrene remediation in drinking water and aquatic environments, while emphasizing the need for further research on polyethylene degradation methods.