Scientists convert PFAS waste into battery-grade lithium

A Rice University–led team reports a process that uses PFAS-saturated activated carbon to extract lithium from high-salinity brine, recovering lithium fluoride at 99% purity and about 82% of available yield. The researchers say the recovered lithium improved lithium‑ion cell capacity in month‑long tests.

Researchers led by Rice University published a Nature Water study describing a method that uses spent PFAS to recover lithium from high-salinity brine. They repurposed PFAS-saturated granular activated carbon, a filtration waste, as an input to capture fluorine for forming lithium fluoride. The team reports recovering lithium fluoride at 99% purity and about 82% of the available lithium fluoride. They also incorporated the recovered material into lithium‑ion cells and observed higher, more consistent capacity over a month. Key details: - The method starts with PFAS-saturated granular activated carbon collected from filters used to remove PFAS from firefighting foam and other sources. - The researchers mixed the PFAS-laden carbon with very salty brine, then rapidly heated the mixture to about 1,000°C and rapidly cooled it, which released fluoride that bonded with positive ions in the brine to form compounds including lithium fluoride. - The team reheated the resulting mixture to lithium fluoride's boiling point (about 1,676°C) to separate and recover lithium, reporting an 82% recovery of available lithium fluoride at 99% purity. - Recovered lithium fluoride was added to lithium‑ion battery electrolytes; after one month, the treated cells showed higher and more consistent capacity compared with control cells. - The authors report the treated carbon became nontoxic waste after processing and argue the method could have a lower environmental impact and greater profit potential than some existing extraction techniques. - The report notes PFAS are widespread, long‑lived manufactured chemicals, and interest in recovering lithium is rising because of growing demand for battery materials. Summary: The study demonstrates a process that repurposes PFAS-contaminated activated carbon to produce battery‑grade lithium fluoride at high purity and substantial yield, with early test results showing improved battery performance. The authors state the treatment renders the carbon nontoxic and argue the approach could reduce environmental impact and increase profitability compared with other methods. Independent expert review and further evaluation of the environmental and economic claims are pending.