PFAS Adsorption on Amine-Functionalized Silica Nanoparticles: Interactions, Mechanisms, and Molecular Insights
Year: 2026
Type: article
Abstract: Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that raise significant concerns, driving the need for improved remediation methods and better understanding of PFAS interactions with sorbent materials. Here, we systematically synthesized and compared a series of amine-functionalized ultraporous mesostructured silica nanoparticles (UMNs), which have previously shown great affinity for a range of PFAS, to investigate the factors governing PFAS interactions with amine-functionalized material surfaces, using both experimental and computational approaches. Similar UMN physicochemical properties allow direct comparison, with the major difference between nanoparticles being the nature of the amine group (primary, secondary, tertiary, or polyamine). Adsorption experiments showed that all UMNs exhibited great affinity across a wide range of PFAS, with particularly strong affinity for longer-chain and more hydrophobic PFAS and sulfonic acids, and only minor variations were observed in their performance among different amine functionalization schemes. pH-dependent studies demonstrated that PFAS adsorption decreased when exposure occurred at pH 11, consistent with amine deprotonation. However, PFAS already bound remain strongly retained on UMNs with less than 10% desorption even at high pHs. Molecular dynamics (MD) simulations and solvation free energy calculations further revealed that PFAS-UMN interactions are mainly driven by the important collaborative contributions of hydrophobic contacts and electrostatic interactions, and the modest contribution of desolvation penalties, giving clear molecular insight into the experimentally observed trends. Overall, this work reveals the chemistry that will drive efficient sorbent-based PFAS removal from contaminated environments.
Language: English
Subfield: Environmental Chemistry
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, University of Minnesota, Minnesota Environment and Natural Resources Trust Fund, Legislative-Citizen Commission on Minnesota Resources, National Institutes of Health, College of Science and Engineering, University of Minnesota, Materials Research Science and Engineering Center, Harvard University, ACS Division of Analytical Chemistry, National Institute of Environmental Health Sciences, Division of Materials Research, Division of Electrical, Communications and Cyber Systems, Division of Chemistry
Awards: G135923551, G1801249269, G259601046, G310967942, G403942265, G4046744693, G4470453470, G4489968610, G4734501518, G5373507601, NSF Center for Sustainable Nanotechnology, G6543735977, G6733614791, G6952772301, G6995829561, G7245116212, G743970376, G7573957695, University of Minnesota Materials Research Science and Engineering Center, NNCI: Midwest Nano Infrastructure Corridor (MINIC), Emerging Water Contaminants: Investigating and Mitigating Exposures and Health Risks, Understanding and Enhancing PFAS Phytoremediation Mechanisms Using Novel Nanomaterials
OpenAlex ID: W7147321832