The widespread occurrence of microplastics in aquatic environments has raised significant environmental concern; however, their distinctive physicochemical properties may also present unconventional opportunities for water treatment. Here, polytetrafluoroethylene (PTFE) microplastics are repurposed as tribocatalytic materials for the degradation of organic pollutants in aqueous media. Mechanical agitation induces contact electrification of PTFE microparticles, resulting in surface charge accumulation and the generation of reactive oxygen species (ROS) without external light irradiation or chemical additives.
Continuous tribocatalytic experiments demonstrated effective degradation of methylene blue (MB), used as a model dye, in a coiled flow inverter (CFI). The reaction was driven by friction generated between dispersed PTFE microplastics in MB solution and the silicon walls of CFI under continuous flow. More than 90 % of MB was degraded within 30 hours through mechanical activation of PTFE particles, which induced radical generation. The degradation kinetics were better described by a biphasic model than by conventional pseudo-first-order kinetics, indicating the presence of distinct fast and slow reaction regimes. Radical scavenging experiments confirmed that superoxide (O₂•⁻) and hydroxyl (•OH) radicals played dominant roles in the degradation process, highlighting the importance of charge-driven interfacial reactions at the PTFE–water interface. Tribocatalytic performance was found to depend on operational parameters, including agitation intensity, particle loading, and dissolved oxygen availability.
This work advances the mechanistic understanding of microplastic-driven tribocatalysis and reframes microplastics from passive contaminants to functional materials. Repurposing PTFE microplastics as tribocatalysts enable a light-independent and energy-efficient approach to water treatment, highlighting new opportunities to exploit abundant polymeric wastes in sustainable advanced oxidation processes.