ERASE-PFAS: Coupling electrified separation and reaction approaches for short-chain PFAS remediation in semiconductor manufacturing

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that are commonly referred to as “forever chemicals” due to their persistence, stability, and resistance to natural environmental degradation processes. During the last two decades, PFAS have been increasingly detected in surface water systems (e.g., lakes and rivers) and groundwater aquifers which serve as sources of drinking water for many communities throughout the United States.

While increasing regulatory measures have led to many long-chain PFAS such perfluoro octane sulfonic acid (PFOS) being phased out, short-chain PFAS (e.g., perfluoroalkane sulfonic acids with six or fewer carbon atoms) are actively being used as alternatives in industries such as the semiconductor industry. In semiconductor manufacturing, short chain PFAS compounds are utilized as functional materials in various unit processes/applications including photoresists, antireflective coatings, wetting agents, etchants, and coolants.

Semiconductor fabs generate significant amounts of wastewater with variable concentrations for short chain PFAS ranging from 10-100 ppt (nanograms/L) to 20 ppm (milligrams/L). The overarching goal of this project is to design, evaluate, and optimize an integrated electrosorption and electrocatalytic process that can selectively extract and degrade short chains PFAS from semiconductor wastewater.

The successful completion of this project will benefit society through the development and implementation of more efficient technologies to treat and remediate industrial wastewater and drinking water sources contaminated by short chain PFAS. Additional benefits to society will be achieved through student education and training including the mentoring of two graduate students at the University of Illinois at Urbana-Champaign.

Because semiconductor wastewater streams typically consist of complex and high turbidity mixtures that contain suspended solids (e.g., silica and cerium nanoparticles), toxic metal ions (e.g., copper) and dissolved organic pollutants (e.g., complexing ligands and surfactants), established and commercial technologies (e.g., ion exchange, sorption with granular activated carbon, and reverse osmosis) cannot effectively extract and destroy short chain PFAS from semiconductor wastewater. A major goal of this project is to advance the fundamental science and engineering knowledge required to develop the next-generation of integrated electrochemical separation and reaction systems that can selectively capture, release, and destroy short-chain PFAS in contaminated water with a focus on wastewater streams from the semiconductor industry.

The specific objectives of the research are to (1) design, synthesize, and characterize electroactive polymer sorbents with high selectivity for short-chain PFAS; (2) evaluate the reactivity of short-chain PFAS at gas-liquid and solid-liquid interfaces to advance the design of electrochemical reactors for PFAS degradation; and (3) evaluate the destruction of short-chain PFAS via coupled electrosorption and electrochemical degradation using plasma and boron-doped, diamond-based electrodes. The successful completion of this project has the potential for transformative impact through the generation of new materials and fundamental knowledge to guide the design, development, and implementation of more efficient technologies to treat and remediate PFAS contaminated wastewater.

To implement the educational and outreach goals of this project, the Principal Investigators (PIs) propose to leverage existing programs at the University of Illinois at Urbana-Champaign (UIUC) such as the Youth in Science and Engineering camps to develop and deliver educational activities for K-12 students including workshops on both water purification and plasma engineering. In addition, the PIs also plan to leverage the UIUC Merrill Scholars Program and the Illinois Undergraduate Scholars Program to recruit and mentor undergraduate students from underrepresented groups to work on the project research activities.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.