Nanoscale Zero Valent Iron-Enabled Treatment Train Approach for PFAS-Contaminated Water

A. Wells Carpenter, J. Darcy, M. Modiri-Gharehveran, L.S. Lee
United States

Keywords: PFAS, nanomaterial, zero valent iron, water, groundwater, contaminant


Per- and polyfluorinated substances (PFAS) are a group of >5,000 chemicals used across wide ranging applications from water-repellent surfaces to Aqueous Film-Forming Foams (AFFF). These “forever chemicals” are known to cause critical health conditions and are not degraded by normal hazardous waste treatment methods. Reports estimate at least $3Bn in PFAS clean-up cost at military installations across the US. Other federal agencies, such as EPA are supporting PFAS cleanup through the Superfund Cleanup Program. Currently used incineration methods are halting around the US due to concerns of ineffectiveness, and landfilling is expected to soon be banned. AxNano LLC has developed RemRx™ ZVI, a patent-pending zero valent iron/nickel (FeNi)-carbon composite engineered to trap and degrade environmental contaminants through effective reductive chemistry. Our innovative approach combines the utility of an iron/nickel (FeNi) alloy to prolong reactivity, nanoscale particles to increase reactive surface areas, and a carbon substrate to target contaminants and improve reactivity by immobilizing the nanoparticles. Preliminary work has shown FeNi-carbon composites’ ability to transform between 30-90% of various PFAS compounds including some of the mostly commonly recalcitrant compounds such as perfluorooctanesulfonic acid (PFOS) and 6:2 Fluorotelomer sulfonate (6:2 FtS). The presentation will include results from feasibility testing of the FeNi-carbon composite in static batch and flowing column studies against PFAS-contaminated water both laboratory-prepared as well as real-world samples of PFAS-contaminated water from a run-off pond at a fire-fighting training facility. Laboratory testing is being used to inform the design, build and pilot testing of a RemRx™ ZVI-enabled contaminated-water treatment train unit. The unit will combine a reductive treatment step by RemRx™ ZVI as well as oxidative treatment step, with the ultimate goal of transforming all PFAS constituents and meeting regulatory requirements for waste disposal. Proposed pilot testing of the unit on PFAS-impacted surface water at a fire-fighting training facility will be presented. As the RemRx™ ZVI technology for PFAS treatment is matured, it may be used to treat other PFAS-containing wastes that threaten human health across the US, such as reverse osmosis rejects, groundwater, landfill leachates, and industrial wastewaters. Of note, the development of this technology is led by a team of female inventors and entrepreneurs, with the support of NIST SBIR and AFWERX SBIR programs.