Joule heat assisting electrochemical degradation of polyethylene microplastics melted on anode

Polyethylene (PE) microplastics (MPs) in water was rapidly degraded using a “Joule heat assisting electrochemical degradation” strategy. In a tailor-made reactor, PE MPs were captured by anode, being softened or even melted by the interface Joule heat, enabling direct electron transfer and making the maximum use of short-lived active species. Within a few hours, above 99 % of PE MPs (∼ 1 g·L⁻¹) vanished, and residual solid products with higher carbonyl index (CI) and O/C ratio inclined to combine, avoiding creating more harmful nanoplastics (NPs), just leaving a few low-threatening soluble products with unsaturated carbon chains. Compared with SO₄^2- and S₂O₈^2-, the presence of Cl^- water matrix could facilitate the chain-scission degradation and make solid products fusion more significant. After proposing a novel MPs degradation mechanism and verifying the universality of this novel strategy by degrading other five kinds of MPs. Subsequently, a techno-economic analysis was conducted.