Enhanced degradation of perfluorooctanoic acid by heat-activated persulfate in the presence of zeolites

The treatment of contaminations with perfluorooctanoic acid (PFOA) is a huge challenge due to its environmental persistence and global distribution. A combination of adsorption and degradation processes is considered as a promising approach for removing PFOA traces from water. In the present study, we developed a novel treatment strategy for PFOA using heat-activated persulfate in the presence of BEA35 - a BEA-structure type zeolite. Our experimental results show for the first time that BEA35 not only removes PFOA by adsorption, but also accelerates its degradation by means of heat-activated persulfate until complete mineralization. The presence of zeolite (50 g L-1) increases PFOA degradation up to 99.8% compared with 58% in homogeneous solution under the same reaction conditions (C0,persulfate = 100 mM, 90 min, 70 °C). The influence of reaction conditions such as pH value, zeolite dosage and type were investigated, and possible reaction mechanisms were considered. The applicability of the zeolite-based treatment system was verified with real groundwater samples. A first cost estimation was provided for the application case of a zeolite fixed-bed adsorber with intermittent regeneration by heat-activated persulfate. The presented approach has the potential to overcome several shortcomings of the existing PFOA degradation technologies, such as high energy demands, vulnerability in complex water matrices, and inefficiency at trace concentration levels. Our findings provide an effective and efficient strategy for treatment of water containing traces of PFOA, which can also inspire the development of remediation technologies for water contaminated by other micropollutants.