Dual-functional metal–organic framework for efficient removal and fluorescent detection of perfluorooctanoic acid (PFOA) from water

Abstract

Perfluorooctanoic acid (PFOA), a synthetic compound belonging to the per- and polyfluoroalkyl substances (PFAS) family, is notorious for its environmental persistence, bioaccumulation potential, and adverse health effects, posing a major challenge to environmental safety. Effective removal and detection of PFOA remains a challenge for conventional capture materials due to its unique molecular structure. In this study, we present a dual-functional metal–organic framework (MOF), UiO-66-N(CH3)3+, specifically designed for selective removal and detection of PFOA in water. This MOF is synthesized through the post-synthetic modification of UiO-66-NH2(Zr) with methyl iodide, introducing partially quaternized ammonium groups that enable ion-exchange functionality. The cationic ammonium groups significantly enhance electrostatic interaction with the anionic PFOA, leading to improved affinity and selectivity. As a result, UiO-66-N(CH3)3+ exhibits outstanding adsorption performance, achieving a high adsorption capacity of 1178 mg g−1 as estimated using the Langmuir isotherm model, along with over 99% removal efficiency within 5 minutes from a 50 ppb PFOA solution. Beyond its high sorption capability, the same MOF is also developed into a highly efficient fluorescence “turn-on” sensor for PFOA detection via a straightforward indicator displacement assay (IDA). In this approach, the MOF is initially loaded with the anionic dye sulforhodamine B (SRB), replacing the original iodide counterions. When bound within the MOF, SRB is nonfluorescent; however, upon exposure to PFOA, it is displaced and regains its strong fluorescence in solution. This rapid fluorescence “turn-on” response enables effective detection of PFOA with both high sensitivity and selectivity. The dual-functional MOF system described herein offers a promising strategy for the integrated detection and removal of PFOA from water, providing a simple yet powerful framework for designing multifunctional MOF-based adsorbents and sensors for PFAS pollutants.

Graphical abstract: Dual-functional metal–organic framework for efficient removal and fluorescent detection of perfluorooctanoic acid (PFOA) from water

Supplementary files

Article information

Article type
Paper
Submitted
01 May 2025
Accepted
15 Jul 2025
First published
15 Jul 2025
This article is Open Access
Creative Commons BY-NC license

J. Mater. Chem. C, 2025, Advance Article

Dual-functional metal–organic framework for efficient removal and fluorescent detection of perfluorooctanoic acid (PFOA) from water

R. Dalapati, J. Shi, M. Hunter and L. Zang, J. Mater. Chem. C, 2025, Advance Article , DOI: 10.1039/D5TC01765C

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