SUMMARY
This invention uses an electrochemical process where a reactive metal is deposited onto a copper electrode in solution to break PFAS bonds, converting these chemicals into harmless fluoride ions and carbon fragments under ambient conditions without catalysts or membranes.
The Unmet Need: Efficient, cost-effective, and environmentally benign PFAS degradation
The field of environmental remediation, particularly for persistent organic pollutants, has been grappling with the challenges posed by per- and polyfluoroalkyl substances (PFAS). PFAS have been recognized as persistent environmental contaminants that pose significant health risks, including cancer and immune system disruptions, due to their extreme chemical stability from strong carbon–fluorine bonds.
Current approaches to PFAS remediation suffer from significant limitations. Many conventional methods require extreme thermal conditions, involve expensive catalysts, or produce incomplete degradation that results in hazardous byproducts or shorter-chain PFAS, which remain problematic. The inefficiencies in electron transfer processes and the reliance on high-energy inputs further complicate these treatments, often precluding sustainable integration with renewable energy sources.
Consequently, there is an ongoing demand for innovative solutions that overcome these energy and process barriers while ensuring complete mineralization of these persistent contaminants.
The Proposed Solution: Reactive metal electrodeposition on a copper working electrode within a single-chamber, membrane-free, and catalyst-free cell
The inventors have developed an electrochemical process that operates in a single-chamber, membrane-free, catalyst-free cell at ambient temperature, where reactive metals such as lithium are electrodeposited onto a copper working electrode in an aprotic, high dielectric constant media containing metal salts. This setup enables the deposited metal to efficiently transfer multiple electrons to PFAS molecules, such as perfluorooctanoic acid, breaking their strong carbon–fluorine bonds to yield fluoride ions and carbon fragments, while minimizing the formation of harmful shorter-chain intermediates.
Experimental validation alongside density functional theory and ab initio molecular dynamics simulations confirms rapid defluorination (95% degradation, 97% defluorination efficiency, and 7.7% Faradaic efficiency), demonstrating that the method achieves nearly complete mineralization under mild conditions.
This approach is differentiated by its operational simplicity and efficiency. Eliminating the need for catalysts, membranes, and high-temperature conditions, it provides a streamlined, energy-efficient method for achieving near-complete mineralization. The process leverages principles from battery chemistry to enhance electron transfer, ensuring swift carbon-fluorine bond cleavage while maintaining high defluorination efficiency. Its ambient operating conditions and compatibility with renewable energy sources further underscore its sustainable and versatile performance against persistent PFAS contaminants.