Magnetic Removal of PFAS from Water — From Molecules to Microplastics

 

Per- and polyfluoroalkyl substances (PFAS) are synthetic compounds known as “forever chemicals,” found in many industrial and everyday products, including nonstick cookware, water- or stain-resistant textiles, food packaging, firefighting foams, laundry detergents, cosmetics, and others. They are among the most problematic contaminants today because of their resistance to chemical degradation by heat, water, and oil. They are extremely persistent and can accumulate in the environment as well as in living organisms, and their removal from water has proved to be very difficult.

In this study, a group of researchers in Germany reported a procedure for removing a broad spectrum of PFAS from water using functionalized magnetic nanoparticles.

Commercial superparamagnetic iron oxide nanoparticles (SPIONs) were used. These nanoparticles, consisting of γ-Fe₂O₃ and with an average diameter of 10.7 nm, were coated with a self-assembled monolayer of different phosphonic acid-based molecules capable of establishing hydrophobic and electrostatic interactions with PFAS. These noncovalent interactions promoted the adsorption of PFAS onto the nanoparticle surface, thereby enabling their removal from water.

The researchers focused on removing PFAS of different sizes, ranging from nanoplastics to fluorinated microplastics found in water used for washing clothes or containing cosmetics. They demonstrated that SPIONs can remove PFAS of different dimensions. Once the PFAS have been removed, the SPIONs can be reused.

This technology was also applied to water sources intended for human consumption, such as river water contaminated by runoff from land or textile washing. The study demonstrated that PFAS concentrations can be reduced by 87%, even below the limit established by German regulations of 100 ng per liter.

The proposed methodology demonstrated its ability to remove contaminants both at the molecular level and as microscopic particles. It highlights the potential of SPIONs as a sustainable platform for treating water containing complex mixtures of these contaminants.

For further information, see Materials Today doi:10.1016/j.mattod.2026.103471