John Foster
University of Michigan, MI·Engineering
Water contaminated with "forever chemicals" is hard to clean up because the carbon–fluorine bonds in these molecules are among the strongest in chemistry. One route is to use plasma — a gas energized until it carries free electrons, charged particles and light — placed in direct contact with water so that electrical energy becomes chemical energy at the surface.
- Fields
Engineering
Physics
Earth & Environmental Science
- Topics
per- and polyfluoroalkyl substances
plasma-liquid interaction
non-equilibrium plasma
- Grants
- 2 known grants, through Jul 2028
What they work on
- Test whether plasma breaks down PFAS through a non-oxidative route in which electrons and photons produce short-lived hydrofluorocarbons that hydroxyl radicals then oxidize to release fluoride ions.
- Tune plasma operating parameters to maximize the flux of electrons and ultraviolet photons reaching the gas–liquid interface, and redesign reactors to improve energy efficiency of defluorination.
- Develop analytical methods able to detect PFAS, PFAS precursors and intermediate byproducts in chemically complex water, and apply machine learning to the resulting datasets to guide process optimization.
- Determine what controls self-organization of the anode attachment in an atmospheric-pressure DC glow discharge over a liquid, identifying the constrained variables that set the size and spatial pattern of the plasma-liquid contact area.
- Measure the role of thermal processes such as evaporation in sustaining the discharge, and characterize the solvated electrons and high-speed liquid droplets, some nanoparticle-laden, that the discharge emits, using optical diagnostics.
More about the research
Work in this group centers on that plasma–liquid boundary: what happens physically where the discharge touches the water, and how those processes can be harnessed to destroy pollutants. Two projects run in parallel, one on the fundamental physics of the discharge-liquid contact region, the other on applying plasma to break down a specific family of persistent contaminants.
Why it matters
Most conventional water treatment cannot remove PFAS, chemicals that persist in drinking water supplies and accumulate in people and wildlife. A plasma process that works even in waste-laden water could give utilities and contaminated sites a way to destroy these compounds rather than just concentrate them, and the work includes a data-sharing platform and workshops intended to support evidence-based policy. The physics results could also inform plasma disinfection of contaminated surfaces and other atmospheric-pressure plasma uses.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Collaborative Research: ECLIPSE-PFAS: Electrical Discharge Plasma-Driven Multidisciplinary Approach for Complete Mineralization of PFAS & PFAS Precursors in Complex Aqueous Systems
NSF · Aug 2025 – Jul 2028
ECLIPSE: CAS-Climate: Understanding the Role of Thermally-Driven Processes in Pattern Formation and Droplet Emission in DC Glows with Applications to Water Treatment
NSF · Jul 2022 – Dec 2026
Closest labs
Sarah Wu
University of Idaho, ID·Engineering
Build theoretical and thermodynamic models of liquid-phase plasma discharge in PFAS solutions to quantify energy delivery, plasma–liquid interactions and the generation of hydrated electrons, free electrons held among water molecules.
Mark Kushner
University of Michigan, MI·Engineering
Develop computational models of the interface between an atmospheric-pressure plasma and water, emphasizing how electrons and ions accelerate into the water surface where PFAS 'forever chemicals' collect.
Peng Zhang
University of Michigan, MI·Engineering
Model theoretically and numerically how photoemitted plasma electrons relax from a direction-dependent velocity distribution to a thermalized state, including the development of plasma waves and instabilities.
The school
University of Michigan: 124 labs on PI Pages, $2.1B a year on research, 963 research doctorates a year.
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