Perfluoroalkyl acids (PFAAs) are chemicals synthesized for industrial use and are found in products such as, non-stick coatings and fire-fighting foam. These chemicals have been identified as contaminants of emerging concern due to their bioaccumulative, persistent and toxic properties. High levels of PFAAs have been found in bodies of water near industries using Teflon and firefighting training facilities, leading to cancer clusters in the surrounding towns. Methods to remove these PFAAs from the water have included filter materials such as activated carbon, resins and clay.  Previous studies of the adsorption capabilities of these materials show promising results.  However, when exposed to PFAAs along with other contaminants and organic compounds, they may not selectively adsorb PFAAs, resulting in detectable levels of PFAAs still present in the filtered water. The goal of this study is to determine a PFAA-selective adsorption method using organically modified montmorillonite with the use of cation exchangeable surfactants. Here, the organically modified silicates (OMS) are synthesized using montmorillonite and a variety of cationic surfactants varying in size and shape.  The OMS are characterized using infrared spectroscopy, powder X-ray diffraction and scanning electron microscopy.  The characterized OMS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) is used to determine the percent PFAA removal.  Initial results indicate 98, 99, and 100 % removal, respectively, of perfluorooctanoic acid (PFOA) for the OMS synthesized from montmorillonite and docdecyltrimethylammonium bromide (DoTMAB) exposed to 10, 100, and 1000 nM PFOA. Ongoing work is focused on the synthesis and evaluation of a variety of OMS for the removal of PFAAs of varying chain length from contaminated water.<br/>

Synthesis and characterization of organically modified montmorillonite for sequestration of perfluoroalkyl acids in contaminated water

255th National Meeting (2018)

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