Catalytic activity and anti-passivation of single iron atoms and atomic clusters co-stabilized on carbonized waste polystyrene plastic

Nanoscale zero-valent iron (n-ZVI) is widely used to efficiently eliminate micropollutants from groundwater, but this is accompanied by rapid passivation in water or air, serious agglomeration, and severe iron leaching. Herein, waste polystyrene plastics are firstly converted into graphitized carbon carriers with large specific surface areas, which serve as the support for iron single atoms/atomic clusters (Fe_SA/AC-N-C_PS). Fe_SA/AC-N-C_PS activating peroxymonosulfate system (Fe_SA/AC-N-C_PS/PMS) can achieve nearly 100% bisphenol A (BPA) degradation within 30 min. The catalytic rate of Fe_SA/AC-N-C_PS is not only 31 times and 20 times higher than that of conventional large n-ZVI (∼70 nm) and small n-ZVI (∼5 nm), respectively, but also exhibits remarkable anti-passivation ability and an extremely low iron leaching (6 μg·L⁻¹), compared to bulk large n-ZVI (1.863 mg·L⁻¹) and small n-ZVI (1.563 mg·L⁻¹). Excellent reactivity and durability of Fe_SA/AC-N-C_PS are benefited from Fe center regulated by pyridine-nitrogen. This work provides a new perspective on the environmental application of waste plastic resource conversion into value-added products.