On-site destruction of recalcitrant perfluoroalkyl substances by molecular sieves

Abstract

A two-stage treatment process for destroying per- and polyfluoroalkyl substances (PFAS) in an aqueous stream. The two-stage treatment process uses a combination of multifunctional crystalline molecular sieves, such as zeolites and zeotypes, to separate PFAS from the aqueous stream, catalytically decompose and defluorinate any PFAS molecules, and generate non-toxic waste products that are safe for disposal. The first stage includes adsorption of the PFAS within one of a pair of vessels containing porous, hydrophobic, hydrothermally stable molecular sieves, dehydration of the captured PFAS on the sieves, and catalytic ozonation of the captured PFAS molecules on the dried sieves. The second stage involves catalytic decomposition and neutralization of the ozonation results with one of a pair of vessels including a zeolite-supported CaO catalyst, catalytic oxidation of any toxic CO generated by the decomposition, and an acid wash for regeneration of the spent catalyst.

Dependencies are inferred from the claim text.