An iron will to take on“forever chemicals”: Ph.D. candidate tackles PFAS with a common metal
When most people think about pollution, they imagine smokestacks or oil spills. But one of today’s most insidious contaminants often comes from something as ordinary as a frying pan. Per- and polyfluoroalkyl substances, or PFAS, are sometimes called “forever chemicals” because they don’t break down easily in nature. They’ve been used for decades in nonstick cookware, firefighting foams, and even cosmetic packaging. But nonstick ironically means these compounds have stuck around—for decades—and now they’re found everywhere from soil to drinking water to human bloodstreams.
At Stevens Institute of Technology, environmental engineering Ph.D. candidate Meng Ji is working on a solution rooted in one of the Earth’s oldest and most abundant materials: iron.
“We demonstrated that iron particles are 26 times more effective than activated carbon, which is a very common used method to treat PFAS and microplastics in a real world per unit surface area,” Ji explained.
A simple, powerful idea
Activated carbon, also known as charcoal, is familiar to many through household water filters (think BRITA™) and has long been used to adsorb PFAS. Absorption is when one substance is taken into the volume of another (like water soaking into a sponge), while adsorption is when particles stick only to the surface of another material, for example, toxins and impurities clinging to the surface of activated carbon in a filter. But Ji and her collaborators wanted to test whether another widely available, low-cost material could do better.
Their research zeroed in on microscale zero-valent iron particles (mZVI), tiny fragments of iron that interact with PFAS at the molecular level. When PFAS-laden water comes into contact with the particles, the hydrophobic portions of the chemicals “stick” to the iron, removing them from the water.
“Activated carbon removes PFAS also through adsorption through a hydrophobic (water-repelling) effect. So they are actually the same mechanism,” Ji said. “But iron is also widely available and cheap, why not use iron? We wanted to do a comparison and then we got this, so we are very excited.”
The results suggest iron is not just comparable to carbon—it’s significantly more effective, offering a promising new tool in the fight against PFAS contamination.
From the lab to the real world
Ji envisions future applications in wastewater treatment and natural water remediation.
“As for water treatment, we want to apply our research at a larger scale — for example, using adsorption to remove contaminants during the dewatering process at construction sites.. Before they discharge water to the public sewer system, construction companies need to treat the contaminated water and make sure it can match the requirements of regulations from the local, state, and federal lawmakers,” she explained. “We hope we can use iron in this process.”
Still, she acknowledges there are hurdles ahead. Iron particles eventually become saturated with PFAS, raising the question of safe disposal or regeneration. Her team is exploring simple solutions, like sodium chloride treatments, to help restore the iron’s effectiveness.
Her findings were recently published in Environmental Science & Technology in a paper titled “Kinetic and Mechanism Study of PFOS Removal by Microscale Zero-Valent Iron from Water”. The study showed that microscale zero-valent iron (mZVI) achieved an areal adsorption capacity for PFOS 26 times greater than that of activated carbon, confirming the material’s potential as a cost-effective, scalable treatment option. Importantly, the research also clarified that the primary removal mechanism was hydrophobic adsorption rather than defluorination or electrostatic attraction, a distinction that will guide future water treatment strategies.
A cultural connection
For Ji, the science and fundamental importance of iron doesn’t end at the lab bench. It extends into her own kitchen, where she draws on a long Chinese tradition of cooking with cast iron. She laughs gently when asked how her family has managed to keep food from sticking to a pan without modern coatings.
“You need to kind of ‘rinse’ a pan before you start to cook,” she explained. “Seasoning a new cat iron pan with pork fat is a traditional method to create a natural, non-stick surface and prevent rust. The process involves heating the pan, rubbing it with a thin layer of rendered port fat, and gradually heating it so the fat bonds to the iron. This forms a durable, protective coating that improves with repeated use. You can test it by frying an egg. A well-seasoned pan should allow the egg to slide easily without sticking. If you succeed, now you know that you have a very perfect iron pot that lasts forever!”
Her advice is practical, but it also reflects a deeper point: for thousands of years, people cooked in iron without needing synthetic chemicals. “Chinese people, we have used the iron pot for many thousands of years,” Ji said. “So we know the method of how to not make food stick in the pan.”
Looking ahead
While industrial applications are still in development, Ji hopes her research will spark broader awareness about the everyday choices people make.
“It’s not a good way to continue to use the no-stick cookware,” she said. “I hope as people learn about the benefits of cooking in the cast iron pan, we can go back to a safer and more traditional way of preparing our food.”
From ancient cooking methods to cutting-edge environmental engineering, Ji’s work shows how old wisdom and new science can converge. In a world struggling with the consequences of “forever chemicals,” her message is simple: sometimes the solution is already in our hands—and our home.
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