Highly Efficient Hydrated Electron Utilization and Reductive Destruction of Perfluoroalkyl Substances Induced by Intermolecular Interaction

Perfluoroalkyl substances (PFASs) are highly toxic synthetic chemicals, which are considered the most persistent organic contaminants in the environment. Previous studies have demonstrated that hydrated electron based techniques could completely destruct these compounds. However, in the reactions, alkaline and anaerobic conditions are generally required or surfactants are involved. Herein, we developed a simple binary composite, only including PFAS and hydrated electron source chemical. The system exhibited high efficiency for the utilization of hydrated electrons to decompose PFASs. By comparing the degradation processes of perfluorooctanoic acid (PFOA) in the presence of seven indole derivatives with different chemical properties, we could conclude that the reaction efficiency was dependent on not only the yield of hydrated electrons but also the interaction between PFOA and indole derivative. Among these derivatives, indole showed the highest degradation performance due to its relatively high ability to generate hydrated electrons, and more importantly, indole could form a hydrogen bonding with PFOA to accelerate the electron transfer. Moreover, the novel composite demonstrated high reaction efficiency even with coexisting humic substance and in a wide pH range (4-10). This study would deepen our understanding of the design of hydrated electron based techniques to treat PFAS-containing wastewater.

Automated summary

A binary composite was developed for the efficient decomposition of PFASs using hydrated electrons, and it was found that the reaction efficiency depended on both the yield of hydrated electrons and the interaction between PFOA and indole derivatives. Among the derivatives, indole exhibited the highest degradation performance due to its ability to generate hydrated electrons and form hydrogen bonding with PFOA.