SURFACE MOLECULAR INTERACTIONS OF BIOGENIC NANOMINERALS

Per- and polyfluoroalkyl substances (PFAS) are a group of non-naturally degrading chemicals used in a wide variety of products for both household and industrial applications. These PFAS molecules accumulate in both the environment (water, soil, and sediments), and in biological systems. They can interact and adsorb on the surface of nanoparticles, particularly biogenic nanominerals, which are naturally coated with biomolecules. Nanomagnetite is an abundant mineral with both abiogenic and biogenic origin, the latter formed in the magnetosome of the magnetotactic bacteria. The energetics of the surface molecular interactions of the most common PFAS - PFOA (perfluorooctanoic acid) with coated nanomagnetite was studied using immersion calorimetry. Two biopolymers: a polysaccharide and a polypeptide were chosen for the surface modification. The experimentally measured heat of interaction of the coated nanoparticles with PFOA shows the difference in their affinity towards the contaminant and provides more insight into the potential role of the biogenic nanoparticles in the environmental transport and bioaccumulation of the PFOA molecules.