Enhanced removal of aromatic emerging contaminants through the electrochemical co-degradation with polystyrene microplastics

The newly developed “Joule heat assisting electrochemical degradation” strategy has been demonstrated as a green and cost-effective strategy for eliminating microplastics (MPs) in water. However, due to their high specific area and abundant surface functional groups, MPs also serve as the ideal carriers for other emerging contaminants in water, and their complexes pose more severe threats to the health of animals and humans. The present study aims to exploit the strong interactions between polystyrene (PS) MPs and four representative aromatic emerging contaminants, in order to potentially enhance the removal these aqueous contaminants through electrochemical co-degradation with PS MPs. Results indicate that PS promotes the degradation of p-benzoquinone or tetracycline, and vice versa. Methylene blue impedes PS degradation, but PS is beneficial to the degradation of methylene blue. Bisphenol A inhibits PS degradation, and vice versa. The different mechanisms were put forward based on universality examination towards more aromatic derivates, sufficient characterizations of pristine MPs and their residual solid and liquid samples, quenching experiment, and DFT calculations. Furthermore, toxicity analysis and techno-economic analysis were also carried out. This study establishes a solid basis for electrochemical co-degradation of MPs and other emerging contaminants in real water matrix in the future.