Chloride-modulated CuFe₂O₄ /Illite for enhanced H₂O₂ activation for glyphosate degradation: Unraveling the active species transformation

The effective degradation of persistent and potentially toxic glyphosate in water remains a challenge. Herein, we report an engineering strategy of chloride-modulated synthesis to fabricate illite-modified CuFe₂O₄ composite (CuFe₂O₄/Illite) as robust heterogeneous Fenton-like catalysts. The optimized catalyst exhibited outstanding glyphosate removal efficiency (98.6% in 60 min), wide pH adaptability (pH 3–11), and excellent stability (87.85% efficiency after four cycles). Chloride ions were found to slightly promote degradation, whereas common anions like HCO₃ - , NO₃ - , and SO₄² - showed mild inhibition. Quenching experiments and electron paramagnetic resonance (EPR) analysis identified •OH and O₂• - as the primary reactive oxygen species, with a minor contribution from ¹O₂ contribution. X-ray photoelectron spectroscopy (XPS) results revealed that the facilitated Cu²⁺/Cu⁺ and Fe³ ⁺/Fe²⁺ redox cycles served as an efficient electron-transfer highway, dramatically enhancing the heterolytic cleavage of H 2 O 2 and the sustained generation of reactive species. Based on liquid chromatography-mass spectrometry (LC-MS) analysis, a degradation pathway involving C-P bond cleavage and side-chain oxidation was proposed, leading to the mineralization of toxic intermediate Aminomethylphosphonic acid (AMPA) into CO₂, NH₄⁺, and PO₄³ - . This work provides a promising catalyst and elucidates the underlying mechanism for glyphosate wastewater remediation.