Degradation of Microplastics by Microbial in Combination with a Micromotor

Abstract

Microplastics, known for their high durability, are pervasive in the environment and pose potential risks to human health via the food chain. Traditional physical and chemical degradation methods often release harmful gases and cause secondary pollution. While biodegradation is a low-carbon, ecofriendly alternative, its slow degradation remains a challenge. Research demonstrates that integrating physicochemical treatments with biological methods can enhance the efficiency of microplastic degradation; yet, major improvements are still needed. Using industrial waste fly ash and g-C₃N₄ as raw materials, we successfully fabricated MnO₂/g-C₃N₄/fly ash (MCNF) micromotors with Fenton reaction and self-propulsion capabilities through calcination and multilayer self-assembly. Notably, these micromotors do not inhibit microbial growth. Pretreatment of polystyrene (PS) with MCNF micromotors achieved a biodegradation rate of 60% within 24 days, while direct addition of MCNF micromotors enabled polyethylene (PE) degradation to reach 66% within 50 days. Compared to biodegradation alone, this combined approach increased the degradation rates of PS and PE by 40 and 24%, respectively. These findings provide a foundation for effective microplastic degradation and highlight the potential of repurposing waste resources.