Superior visible light-mediated catalytic activity of a novel N-doped, Fe3O4-incorporating MgO nanosheet in presence of PMS: Imidacloprid degradation and implications on simultaneous bacterial inactivation

Abstract

Impressive Imidacloprid (IMD) degradation and bacterial inactivation were attained through the photocatalytic activation of peroxymonosulfate (PMS) via a novel, N-doped MgO@Fe₃O₄, under visible light. After complete characterization (XPS, XRD, FT-IR, FE-SEM, EDX, HRTEM, DRS, BET, VSM, and EIS), using [PMS]=75 mg/L, [N-MgO@Fe₃O₄]=150 mg/L at pH=5.6, around 95% of 10 mg/L IMD was degraded within 60 min; highly synergic interactions between the various catalytic routes were revealed. Extensive scavenger tests and EPR studies revealed that SO₄^•-, HO^•, and ¹O₂ are generated and play a key role in IMD degradation. Tap water experiments proceeded unhindered, and only the presence of high HCO₃^- and PO₄^3- concentration resulted in a decrease in the IMD degradation efficiency, while negligible leaching, magnetization, notable separation, and reusability properties were well-preserved for six repetitive cycles. Finally, E. coli disinfection was achieved before IMD degradation, possibly affected by its transformation byproducts. The overall efficacy of N-MgO@Fe₃O₄ indicated the potential for implementation in contaminated waters.