A recent study introduces an innovative electrochemical approach for capturing, concentrating, and eliminating various chemicals known as PFAS—specifically the increasingly common ultra-short-chain PFAS—from water in a seamless process. This breakthrough is set to tackle the escalating issue of per- and polyfluoroalkyl substance contamination, particularly in semiconductor manufacturing.
A University of Illinois Urbana-Champaign study is the first to describe an electrochemical strategy to capture, concentrate and destroy mixtures of diverse chemicals known as PFAS — including the increasingly prevalent ultra-short-chain PFAS — from water in a single process. This new development is poised to address the growing industrial problem of contamination with per- and polyfluoroalkyl substances, particularly in semiconductor manufacturing.
Earlier research from U. of I. revealed that short- and long-chain PFAS could be removed from water through a method called electrosorption. However, this technique proved ineffective for ultra-short-chain PFAS due to their small size and distinct chemical characteristics. The latest study, led by Professor Xiao Su from the Illinois Department of Chemical and Biomolecular Engineering, merges a desalination technology known as redox electrodialysis with electrosorption in a single apparatus, aiming to capture a complete range of PFAS molecules.
The results of this study are detailed in the journal Nature Communications.
“We opted for redox electrodialysis because ultra-short-chain PFAS behave similarly to salt ions in water,” Su explained. “Our goal was to create an efficient electrodialysis system that could capture ultra-short-chain PFAS while simultaneously working with electrosorption for longer-chain PFAS, enabling their destruction through electrochemical oxidation—all within one device.”
Su’s team has previously created highly efficient electrodialysis systems capable of removing various contaminants. However, traditional methods required expensive ion-exchange membranes, which quickly became clogged with PFAS molecules.
To overcome this challenge, Su’s team developed a cost-effective nanofiltration membrane that allows for electric-field-driven PFAS removal without the fouling issues. This advancement builds on their previous work that combined redox polymers with nanofiltration membranes for energy-efficient desalination.
Finding the appropriate materials for PFAS removal is crucial, but determining the most effective system design adds another layer of complexity.
“After testing numerous configurations, we found a setup that first desalinates the contaminated water, removing ultra-short-chain PFAS, while carbon electrodes simultaneously extract the remaining short- and long-chain molecules,” Su stated. “This process also concentrates the PFAS, facilitating their easier destruction after capture.”
Ultimately, the electrochemical oxidation integral to redox electrodialysis converts the captured PFAS into fluoride ions, a vital step in eliminating these stubborn contaminants from our environment.
Su expressed enthusiasm about the potential to scale up this method, aiming to transition it from the laboratory to practical applications, including direct integration into industrial wastewater systems.
“This research comes at a critical time, driven by growing interest from the U.S. government, wastewater treatment plants, and the semiconductor sector,” Su remarked. “As semiconductor production is expected to increase in the coming years, addressing PFAS removal for sustainable manufacturing will be an increasingly important issue.”
Illinois researchers Nayeong Kim, Johannes Elbert, and Ekaterina Shchukina also contributed to this study, which was supported by the National Science Foundation ERASE-PFAS program. Su also has affiliations with civil and environmental engineering, chemistry, and the Beckman Institute for Advanced Science and Technology at the U. of I.
