The Removal of Long & Short Chain Perfluoroalkyl Substances via Granular Activated Carbn Adsorption

Per- and polyfluoroalkyl substances (PFASs) and used in many industrial and commercial applications including non-stick cookware, stain resistant fabrics, food packaging, as well as fire fighting foam products, such as those used in civilian and military aviation firefighting. They are problematic because of their persistence in the environment and their long half-life in humans. The two major PFASs of interest are perfluoro octanesulfonic acid (PFOS) and perfluoro octanoic acid (PFOA) due to their predominance in the above applications and associated USEPA Health Advisory Level of 70 ng/L (ppt). This paper cites test results relating to the removal of PFOA and PFOS via granular activated carbon (GAC) adsorption, as well as results exploring GAC efficacy for removal of other PFASs, specifically those with a shorter carbon chain length.

The USEPA recommends GAC adsorption as effective treatment technology for the removal of both PFOA and PFOS. This paper outlines the ability of domestic reagglomerated bituminous coal-based activated carbon to remove PFCs to non-detectable levels (< 2 ppt) and compares its performance to other GAC products in two groundwater well sites located in PA. The specific targeted PFCs are:

• Perfluoro butanoic acid (PFBA)
• Perfluoro butanesulfonic acid (PFBS)
• Perfluoro hexanoic acid (PFHxA)
• Perfluoro hexanesulfonic acid (PFHxS)
• Perfluoro octanoic acid (PFOA)
• Perfluoro octanesulfonic acid (PFOA)

The overall objective of this paper is to reinforce the EPA’s guidelines that granular activated carbon is one of the best available treatment technologies for the removal of PFCs like PFOA and PFOS, but also show that GAC can be highly effective for removal of shorter chain perfluoroalkyl substances.