Degradation of Aqueous Perfluorooctanoic Acid by Iron-Activated Persulfate Oxidation

Abstract

Perfluorinated compounds (PFCs) are a class emerging contaminants that have been implicated in bladder cancer and other human health problems. Due to the widespread exposure to humans, persistence in the environment, and their negative effects on human health, we need to develop a treatment method to degrade these chemicals into harmless species. Perfluorooctanoic acid (PFOA, C₈HF₁₅O₂) is one of the top representatives of PFCs commonly reported to be found in water sources, hence it was chosen as the model compound and focus in this project. We examined an iron-activated persulfate oxidation (IAPO) method to decompose aqueous PFOA, and tested the reaction under various conditions, including: oxic, anoxic, and anoxic/dark conditions. We observed 𝑐𝑎. 64% of PFOA (beginning with solution phase concentration fo 𝑐𝑎. 1.64*10⁻⁶ mol L⁻¹) was transformed after four hours under anoxic conditions. This was about seven times higher than measured under oxic conditions, and about five times higher than anoxic/dark conditions. Therefore, we concluded that IAPO can decompose PFOA at 25 °C, the ambient condition temperature. This method can potentially be used as an inexpensive and environmentally-friendly PFOA remediation method, with potential application to other PFCs in groundwater and soil. In addition, this method may be applicable for surface water sources such as potable water reservoirs, waste water effluent, and extracted groundwater.