(245g) Separation and Destruction of per and Polyfluoroalkyl Substances through Galvanic Reaction

Per and polyfluoroalkyl substances, or PFAs for short, are a rapidly growing concern due to recent studies connecting PFA exposure to cancer and immune system problems. With over 9000 PFA variants identified to date, research into the removal and destruction of these molecules is vital to the health and safety of the world population. Two common PFA molecules are perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA); the EPA has published health advisory limits of 0.02 ppt and 0.004 ppt for drinking water, respectively, and maximum contaminant levels of 4.0 ppt for both contaminants. These low concentration requirements make remediation methods such as filtration and/or incineration ineffective, cost prohibitive, or environmentally damaging. Our process combines a continuous flow reactor with an electroless electrochemical reaction, requiring no external energy. We’ve determined that PFOA and PFOS can be separated, concentrated, and destroyed from water sources ranging from drinking water to landfill leachate using our continuous galvanic reactor. Our experiments show a 95% reduction in PFA molecules after a single treatment stage; higher removal can be achieved using multiple stages. Experiments show that residence time can be reduced to minutes instead of hours, with waste concentration ratios exceeding 500:1. Once concentrated, we can destroy these contaminants using electrolysis, chemical oxidation, or thermal decomposition, resulting in complete mineralization of the original contaminants. This process provides a simple, scalable, and inexpensive resolution to an emerging global environmental issue.