Thermal Behavior of Perfluorooctanoic Acid Adsorbed on Granular Activated Carbon

In this study, an experiment to investigate the thermal behavior of perfluorooctanoic acid (PFOA) adsorbed on granular activated carbon (GAC) was carried out. PFOA of a known amount adsorbed by GAC was heated by an electric furnace with a gas mixture of oxygen and nitrogen being used for the carrier gas. The samples were analyzed by using LC/MS/MS, an ion chromatograph, and an atmospheric pressure helium- radiofrequency barrier plasma discharge-atomic emission spectrometry (He-rfBD-AES) to analyze the behavior of PFOA from form changes and the mass balance of F. A heating experiment of PFOA was also carried for a comparison. When PFOA was heated, it evaporated at 150°C and 300°C. The generation of fluoride and decomposition compounds along with the combustion was confirmed at 500°C. When PFOA adsorbed by GAC was heated, PFOA and the homologues did not evaporate at 150°C. Additionally, the generation of fluoride was confirmed at 150°C and 300°C. It was indicated that GAC inhibits the evaporation of PFOA, and facilitates the combustion reaction of PFOA compared with when PFOA was heated without using GAC.