Fe-Enriched electron transport in CuFeS2 Catalyzed peracetic acid for efficient dipyrone Degradation: Computational and experimental Insights

The increasing presence of pharmaceutical contaminants, such as dipyrone (DIP), in water systems highlights the urgent need for innovative and sustainable remediation technologies. This study examined the degradation of DIP using a chalcopyrite (CP)-activated peracetic acid (PAA) system, highlighting its potential for the removal of pharmaceutical pollutants. Experimental and statistical parameter optimization suggested that approximately 85.5 % of DIP degradation and 60 % of mineralization were achieved with CP (4 g/L) and PAA (10 mM) at neutral pH. Scavenger and probe experiments confirmed the presence of hydroxyl radicals ( • OH) and alkyl radical species in the CP/PAA system, but •OH was the primary contributor to DIP degradation. The surface-active sites confirmed that heterogeneous Cu(I) exerted more significant influence than Fe (II) of CP, producing 4.21 and 2.35 mg/L, respectively. The presence of reductive sulfur species in the CP allowed the capture of additional protons, creating sulfur vacancies and further strengthening the cycling of Cu and Fe species. DFT analysis confirmed that the FeCuS 2 -Fe adsorption energy (−3.71 eV) and the HOMO-LUMO gap of FeCuS 2 -Fe (0.03 eV) were critical to produce radicals. The CP/PAA system is suitable for DIP degradation and contributes significantly to the degradation of other environmental pollutants. It retained its capacity to degrade above 65 % for up to five consecutive cycles, offering a new and innovative method for water treatment.