Per-and polyfluoroalkyl substances (PFAS) are one of important issues due to its widespread, persistence in the environment. Among PFAS, electrocoagulation of perfluorooctanoic acid (PFOA) in water using iron electrode was investigated. An increase in current density from 2.4 to 80 mA cm-2 led to a significant increase in the removal efficiency of PFOA from 10 to 100% within 6 hours. The electrocoagulation degradation of PFOA followed pseudo-first order kinetics and the k value was from 0.017 to 0.836 h-1 at from 2.4 to 80 mA cm-2. Kinetic investigations demonstrated that the degradation rate constant increased with the increasing applied current density. Under the optimum condition, the removal of TOC and the EEO for PFOA degradation were 60% and 23.2 Wh L-1, with short half-life time (1 h and 13 min). In addition, defluorination was observed by fluoride release of 20% within 6 hours with 100% removal of PFOA. Finally, production of shorter-chain perfluorocarboxylates such as PFPeA, PFHxA, and PFHpA along with formate and fluoride ions were observed as byproducts from PFOA removal. Using the identified byproducts, PFOA degradation mechanism during electrocoagulation was proposed.

Removal and degradation mechanism of perfluorooctanoic acid (PFOA) during electrocoagulation

2019 Spring National Meeting

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