Contact-Electro-Catalysis for the Degradation of Pentachlorophenol Using Inert Fluorinated Ethylene Propylene Powders

Abstract

Chlorophenols (CPs) pose significant risks to human health due to their toxicity and carcinogenic properties. The direct oxidative breakdown of CPs can produce even more harmful byproducts, resulting in secondary pollution. There is a pressing need for a technology capable of both reducing and oxidizing CPs for their removal. For this research, we utilized commercially accessible organic polymer fluorinated ethylene propylene (FEP) as a catalyst, activated through ultrasound to kickstart a contact-electro-catalysis process to degrade pentachlorophenol (PCP). A proposed mechanism is presented for the reduction and oxidative breakdown of PCP relying on contact electrification-induced electron transfer that creates reactive species. Experimental findings demonstrate that PCP can be completely degraded with only 1.0 mg of FEP. Experiments on identifying and quenching reactive oxygen species indicate that ^•O₂⁻, ^•OH, and ¹O₂ play a role in the degradation process. The degradation of PCP involves four pathways: direct dechlorination, hydroxylation dechlorination, oxidation, and polymerization. Toxicity assessment reveals that the dechlorination process notably decreases the toxicity of intermediates. Furthermore, characterization and cycling experiments demonstrate the outstanding stability and recyclability of FEP, making it suitable for real environmental water applications. Ultrasound-driven contact-electro-catalysis system offers a straightforward, economical, and eco-friendly approach to degrade PCP. It offers valuable insights for potentially treating stubborn CPs effectively.