Capacitive removal of PFOA and PFOS from Drinking Water

Polyfluoroalkyl and perfluoroalkyl compounds (PFCs) have been used commercially since the 1940’s due to their high level of chemical stability, almost frictionless surface or waterproofing characteristics. Elevated levels of PFCs have been linked to cancer and other health problems including reproductive and developmental risks. PFOA and PFOS are amongst the most prevalent of the PFCs with low levels been found in everyone blood especially in areas where the drinking water contains high levels of PFOA/PFOS due to industrial activity. The EPA has established a limit of less than 70 ng/L. A range of approaches have been investigated to remove PFCs. While these can be effective they have issues and there is need for improved and flexible solution for removing them from drinking water and capturing the PFOA/PFOS so it can be destroyed and removed from the environment. In the Phase I, Mainstream proposes to leverage our high performance capacitive deionization technology for the removal of PFCs from drinking water. The Mainstream CDI technology has been shown to be an energy efficient, high performance approach for the removal of low levels of ions from aqueous solutions. In the proposed Phase I, Mainstream will modify our electrode system to optimize the adsorption of PFOA and PFOS from drinking water. In Phase I, we use of capacitive deionization system to optimize the adsorption rate and process conditions for the removal and the concentration of the rejected PFOA/PFOS molecules. Mainstream CDI system allows the rejection of the retained species into a concentrate waste stream thereby increasing the process efficiency, maximizing environmental benefit and lowering the overall process costs. In Phase II, Mainstream expects build prototype demonstration units for the continuous clean-up of drinking waters with high PFOA/PFOS levels.