Bio-templated micromotors for simultaneous adsorption and degradation of microplastics

Abstract

Microplastic contamination has increasingly become a focus of public attention due to its ubiquity on earth. As the appearance of microplastics in the human body has raised great concerns about their effects on human health, it is imperative to develop efficient technologies to remove microplastics. In this work, taking advantage of the hollow structure of kapok fibers and low-cost MnO2 catalyst, a tubular self-driven micromotor was synthesized for simultaneous adsorption and degradation of microplastics. Functionalization with polydopamine endowed the micromotors with the ability of on-the-fly capture of microplastics. Attributed to the enhanced diffusion caused by the self-propulsion, the propelled micromotors exhibited an adsorption efficiency 3.41 times that of static micromotors, achieving a removal ratio of 73.57 % in 1 mg/mL polystyrene microspheres dispersion in 30 min without external stirring, which poses a prospective approach for in-situ removal of microplastics. In addition, coupling with photocatalytic CdS, the formed CdS/PDA heterojunction could generate photo-induced charge carriers, which together with the active species produced through the Fenton-like processes contributed to the degradation of microplastics. This work proposed a new platform for the simultaneous adsorption and degradation of microplastics and may provide implications for the removal of microplastics in the environment.