Polytetrafluoroethylene mediated contact-electro-catalysis enhanced permanganate activation: unraveled mechanism involving singlet oxygen and manganese species

Abstract

In this study, a contact-electro-catalysis system was developed for activating permanganate (Mn(VII)) using polytetrafluoroethylene (PTFE). With ultrasound assistance, charge transfer between the water molecules and the PTFE surface generates excited-state PTFE, which captures dissolved oxygen to continuously produce reactive oxygen species ({\text{O}}_{\text{2}}^{\text{•}-} and ¹O₂). Electrons from the excited-state PTFE activated Mn(VII) to reactive intermediates Mn(VI) and Mn(V), whereas in situ H₂O₂ further promoted Mn(VII) activation and ¹O₂ formation. The system efficiently degraded Rhodamine B and Methylene Blue, achieving rates more than twice those of Mn(VII) alone and over 25 times higher than those of the ultrasonic PTFE system. The PTFE exhibited excellent stability and reusability, maintaining removal rates above 90% for Rhodamine B and 80% for Methylene Blue after 10 consecutive cycles. These results demonstrate a mechanically driven, environmentally benign strategy for activating high-valent metal oxidants, providing mechanistic insights into the rational design and construction of sustainable, efficient advanced oxidation systems for environmental remediation applications.

Graphical abstract

Keywords

Contact-electro-catalysis / Potassium permanganate / Reactive manganese species / Radicals formed in situ / Sustainable cycle

Highlight

	● PTFE-mediated contact-electro-catalysis was developed for Mn(VII) activation.
	● Ultrasound-driven CEC continuously generates reactive oxygen species.
	● Mn(VII) accepts electrons from excited PTFE, forming reactive Mn(VI) and Mn(V).
	● In situ H2O2 promotes 1O2 formation via Mn(VII) activation.
	● The US-PTFE-Mn(VII) system exhibits excellent dye degradation & practical potential.

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