Per- and polyfluoroalkyl substances (PFAS) contamination in water poses a significant challenge due to its persistence in the environment and detrimental effects on human health. Thus, developing an innovative strategy to completely destroy PFAS in water is inevitable. In this regard, we developed a novel degradation strategy for perfluorooctanoic acid (PFOA; C7F15COOH), one major class of PFAS, by employing advanced oxidation routes with tailored zeolites materials. Zeolites are crystalline and microporous materials and have shown promise for PFOA adsorptive removal. In this study, we investigated the effects of zeolite micropores on thermal PFOA destruction at reaction temperature below 100 °C using zeolite BEA (with 0.75 nm micropore), MFI (with 0.56 nm micropore) and LTA (with 0.40 nm micropore). It was observed that BEA and MFI zeolites were effective in breaking C-F bonds of PFOA, while LTA was not, mainly due to limited micropore dimensions compared with PFOA molecular size of ~0.5 nm. During the PFOA degradation over these series of catalysts, PFOA molecules underwent gradual C-F bond destruction of the molecules, leading to corresponding products (e.g., C6F13COOH, C5F11COOH and CF3COOH) as intermediates. Control experiments without any solid catalysts revealed that PFOA degradation rates of zeolite catalysts were ~5 folder faster than homogeneous reactions under identical reaction conditions. These results demonstrate zeolites’ superior degradation performance of PFOA via heterogeneous catalysis. Therefore, our findings will open a new avenue for zeolite-enabled thermal degradation of PFOA, laying a foundational basis for further catalyst development for PFAS destruction technologies.
