Reviewed by Lexie CornerMay 28 2025
Researchers have investigated the most effective way to remove contaminants from water. Their findings were published in ACS Publications on March 19, 2025.
Doctoral student Meng Ji working in the lab with Stevens professors Xiaoguang Meng and Christos Christodoulatos. Image Credit: Stevens Institute of Technology
PFOS (perfluorooctane sulfonate), part of the broader group of PFAS (per- and polyfluoroalkyl substances), are synthetic chemicals widely used in products designed to resist stains, water, grease, and fire. Common applications include non-stick cookware, carpets, upholstered furniture, food packaging, and firefighting foams at airports and military sites.
Due to their persistence in the environment, PFOS are often referred to as “forever chemicals.” Their widespread use has led to contamination of soil, agricultural products, and water supplies, raising concerns about health effects such as liver disease, immune dysfunction, developmental issues, and cancer.
A research team from the Stevens Institute of Technology—including Professors Xiaoguang Meng and Christos Christodoulatos, and Ph.D. student Meng Ji—sought to determine the most efficient method for removing PFOS from water.
Most conventional filters rely on activated carbon, which removes contaminants through adsorption—a process in which PFOS molecules adhere to the porous surface of carbon particles as water passes through.
Another treatment method uses microscale zero-valent iron (mZVI), or iron powder, which is commonly applied in the wastewater industry to break down and remove pollutants from treated water.
Iron powder is commonly used for water treatment and wastewater treatment, because it is cheap it is cheaper than activated carbon.
Xiaoguang Meng, Professor, Department of Civil, Environmental and Ocean Engineering, Stevens Institute of Technology
The researchers set out to compare the adsorption capacity of iron powder and activated carbon. Their findings showed that iron powder was more effective at removing PFOS from water.
The iron powder was 26 times more effective than activated carbon per unit surface area.
Meng Ji, Ph.D. Student, Stevens Institute of Technology
They observed that even after the iron powder rusted in water, its adsorption performance remained largely consistent.
“The particles’ surface is covered by iron oxide, but it is still very active, and that is surprising,” added Meng
This suggests that the oxidized iron continues to play a role in removing PFOS, a result the team found astonishing. According to Meng, the study has attracted attention among researchers; despite its recent publication, it has already been viewed over 1,000 times.
Meng and Ji plan to continue exploring the mechanisms behind this phenomenon.
Meng concluded, “Now we need to do more research to find out why. Because this is important for the development of large-scale removal technologies.”
Journal Reference:
Ji, M., et al. (2025) Kinetic and Mechanism Study of PFOS Removal by Microscale Zero-Valent Iron from Water. Environmental Science & Technology. doi.org/10.1021/acs.est.4c12301.