Among the most stubborn legacies of industrial chemistry are PFAS — molecules so stable they have earned the name 'forever chemicals,' accumulating in soil, water, and living tissue with no natural exit. Susanna Maisto, a doctoral chemist at Yale University, has spent five years pursuing not containment but destruction, developing a method that chemically transforms PFAS molecules until they can no longer hide in water and can finally be broken apart. Her work, defended in July 2026, points toward a future where manufacturers intercept contamination at its source rather than leaving communitie
Yale chemist develops method to double PFAS size, enabling destruction of 'forever chemicals'
Two separate problems collapse into one.
Mark
Why does the size matter? If you're destroying the molecule anyway, why does it need to get bigger first?
Mimi
Because size changes solubility. A PFAS molecule is tiny and loves water—that's the whole problem. When you double its size with octanol, it suddenly hates water and falls out of solution. That separation is what lets you then destroy it efficiently. You're not just breaking bonds randomly; you're creating a molecule that wants to leave the water phase.
Mark
And the octanol itself—does that persist? Does it become another forever chemical?
Mimi
No. Octanol is a regular alcohol. It breaks down naturally. The whole point is you're converting something indestructible into something that isn't.
Mark
You mentioned it works best in concentrated waste streams. That sounds limiting.
Mimi
It is, in a way. This isn't a tool for cleaning up a contaminated aquifer. It's for catching PFAS at the moment it leaves a factory. That's actually where you want to intervene—before it spreads.
Mark
How long until a semiconductor fab could actually use this?
Mimi
That's the next phase. The chemistry works. Now it needs to be scaled, tested in real industrial conditions, and integrated into existing wastewater systems. That's engineering, not discovery.
The Pulse
- PFAS chemicals bond so tenaciously that every existing treatment method merely relocates the problem — activated carbon, reverse osmosis, all of it moves contamination without ending it.
- Maisto's esterification process uses octanol to double the size of PFAS molecules, forcing them out of solution and into a state where destruction becomes chemically feasible — collapsing two problems into a single 24-hour reaction.
- The method works across a wide range of PFAS types, including newer replacement compounds that have defeated existing treatments, and holds up even in dirty or saline water.
- Because the reaction performs best at high concentrations, the technology is aimed squarely at industrial point sources — semiconductor plants and manufacturing facilities — where contamination can be stopped before it ever reaches a water supply.
- The path from dissertation to deployment remains open: whether industry will adopt the method is now the defining question.
Among the most stubborn legacies of industrial chemistry are PFAS — molecules so stable they have earned the name 'forever chemicals,' accumulating in soil, water, and living tissue with no natural exit. Susanna Maisto, a doctoral chemist at Yale University, has spent five years pursuing not containment but destruction, developing a method that chemically transforms PFAS molecules until they can no longer hide in water and can finally be broken apart. Her work, defended in July 2026, points toward a future where manufacturers intercept contamination at its source rather than leaving communities to inherit the consequences downstream.
The carbon-fluorine bond — the strongest single connection in organic chemistry — is what makes PFAS so useful to industry and so devastating to the environment. Repeated dozens of times over, it produces molecules that don't degrade in soil, water, or living tissue. They simply accumulate, indefinitely.
Susanna Maisto, a fifth-year doctoral student in Professor John Fortner's lab at Yale University, chose to pursue destruction rather than containment. Conventional approaches treat PFAS like fugitives to be caught — activated carbon absorbs them, reverse osmosis filters them out — but neither method actually eliminates anything. Maisto's approach rewires the molecule itself. By introducing octanol, a chemical relative of ordinary alcohol, she causes PFAS to roughly double in size. The enlarged molecule separates naturally from water, and crucially, the same reaction that makes it insoluble also makes it far easier to destroy. Two problems resolve in one step.
The deeper challenge was making an organic reaction work in water at all. Maisto borrowed a technique from University of Tokyo researchers, breaking PFAS into microscopic suspended droplets that act as tiny reaction chambers. The full process takes about 24 hours, works across a wide range of PFAS types including newer replacement compounds, and functions even in contaminated or saline water.
Her data revealed that the reaction performs best at high PFAS concentrations — a finding that shaped her vision for deployment. Rather than treating diluted contamination already spread through municipal systems, the technology is designed for industrial point sources: semiconductor fabrication plants and manufacturing facilities, right where PFAS enter the water stream. The goal is prevention, not cleanup.
The discovery emerged from three years of painstaking troubleshooting after her advisor pointed her toward carboxylic acid chemistry in her first year. Cracking the concentration puzzle, and later solving the destruction chemistry, became the most satisfying moments of her doctoral work. Whether industry will now adopt what she found is the question that remains.
The carbon-fluorine bond is the strongest single connection in organic chemistry. Repeat it dozens of times over, and you get what chemists call a forever chemical—per- and polyfluoroalkyl substances, or PFAS. Industry loves them for exactly this reason: they don't break down. That's what makes them perfect for nonstick cookware, water-resistant fabrics, semiconductor manufacturing. It's also what makes them a nightmare for regulators. Once PFAS enter soil, water, or living tissue, they stay there. They don't degrade. They accumulate.
Susanna Maisto, a fifth-year doctoral student at Yale University working in Professor John Fortner's lab, spent her dissertation hunting for a way to actually destroy these molecules rather than just trap them. She defended her research in late July, and what she found could reshape how manufacturers handle PFAS before it ever reaches a community's water supply.
The conventional approach treats PFAS like a fugitive to be caught. Activated carbon absorbs it. Reverse osmosis filters it out. Both methods are expensive, and neither actually destroys anything—they just move the problem elsewhere. Maisto's strategy is different. She chemically rewires the molecule itself. Her method introduces octanol, a chemical relative of ordinary alcohol, which attaches to a PFAS molecule and roughly doubles its size. The enlarged molecule no longer dissolves in water, so it separates out naturally. And here's the crucial part: the same reaction that makes it insoluble also makes it far easier to destroy. Two separate problems collapse into one.
The real trick was making an organic reaction happen in water at all. Organic chemistry doesn't typically work that way. Maisto borrowed a technique first published by University of Tokyo researchers in 2002, which breaks PFAS into microscopic droplets suspended in the water. These tiny droplets act as microreactors, giving the octanol and PFAS somewhere to actually meet and react. The full process takes about 24 hours. It works across a wide range of PFAS types, including newer replacement compounds that have resisted existing treatment methods. It even functions in dirty water thick with organic matter and in saltwater, though salt does reduce efficiency somewhat—a reasonable trade-off given that the reaction is happening in water in the first place.
Maisto's data revealed something important: the reaction performs best when the water is already heavily contaminated with PFAS. This concentration dependence points directly to where she envisions the technology being deployed: at the source. Not in municipal water systems treating diluted contamination that's already spread. Instead, at semiconductor fabrication plants and manufacturing facilities, right where PFAS leave the industrial process and before it ever enters the broader water supply. The goal isn't cleanup. It's prevention.
The discovery came almost by accident. At the end of her first year at Yale, Maisto's advisor suggested she read about carboxylic acid reactions in the library—the chemical class that encompasses many PFAS. Three years of troubleshooting followed. For months, the reaction seemed to work only at high PFAS concentrations, stalling when levels dropped. Cracking that puzzle, and later solving the destruction chemistry itself, became some of the most satisfying moments of her doctoral work. Now the question is whether industry will adopt it.
Notable Quotes
The reaction performs best when water is already heavily contaminated with PFAS, pointing to deployment at industrial sources rather than municipal systems.— Research findings from Susanna Maisto's dissertation
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