Researchers from the Price College of Engineering at the University of Utah have developed a groundbreaking material that addresses one of today’s most urgent environmental challenges: the efficient removal and real-time detection of perfluorooctanoic acid (PFOA), a toxic and persistent member of the PFAS “forever chemicals” family, from contaminated water.
In a recent study published in the Journal of Materials Chemistry C, Ling Zang, professor in the Department of Materials Science and Engineering, and his research team introduced a dual-functional metal-organic framework (MOF) known as UiO-66-N(CH₃)₃⁺.
This new MOF demonstrates exceptional capabilities in both PFOA adsorption and fluorescence-based detection; the MOF literally lights up when it binds to the pollutant, making it easier to quantify the scale of the problem and the rate and efficiency of remediation. The MOF also exhibits excellent reusability, as tested through repeated adsorption–desorption cycles. After each adsorption, the material could be readily regenerated by simple washing.
Zang and his colleagues constructed their MOF via post-synthetic modification of another widely studied MOF, known as UiO-66-NH₂, a material recognized for its high porosity and potential in water treatment applications. However, when applied to removal of PFOA, the adsorption capacity of UiO-66-NH₂ is limited due to weak binding interactions. To address this, the researchers incorporated quaternary ammonium groups that enhance electrostatic interactions with PFOA, leading to a 3.4-fold increase in adsorption capacity compared to the parent UiO-66-NH₂ framework. The cationic groups also work synergistically with the MOF’s metal-binding sites, achieving highly selectivity and efficiency in contaminant capture.
Key Technological Breakthroughs
- Record-High Adsorption Capacity
UiO-66-N(CH₃)₃⁺ achieves a maximum PFOA adsorption capacity of 1178 mg/g, as determined by Langmuir isotherm modeling, far surpassing conventional sorbents such as activated carbon and unmodified MOFs. This sets a new benchmark for PFOA uptake in the field. - Ultra-Fast Removal Performance
Thanks to its highly porous, interconnected structure, the MOF removes nearly 100% of PFOA from 50 ppb aqueous solutions within 5 minutes. This sort of rapid treatment is crucial for real-world applications. - High Selectivity and Salt Tolerance
The MOF exhibits strong selectivity for PFOA even in the presence of other PFAS compounds, salts, and natural organic matter, ensuring reliable performance in complex environmental conditions. - Robust Reusability
The material maintains over 93% adsorption capacity after five regeneration cycles, making it both cost-effective and environmentally sustainable. - Integrated Fluorescent Sensing for Real-Time Monitoring
Beyond removal, UiO-66-N(CH₃)₃⁺ functions as a highly sensitive “turn-on” fluorescent sensor for PFOA using an indicator displacement assay (IDA). This enables real-time, on-site quantification of PFOA concentrations, offering a user-friendly and rapid alternative to traditional lab-based techniques.
“This MOF represents a major leap forward for PFAS remediation,” said Rana Dalapati, the study’s lead author. “Its ability to both selectively capture and sensitively detect PFOA in real time makes it a versatile and practical solution for water treatment and environmental monitoring.”
Impact and Future Outlook
PFOA, a widely used industrial chemical, is notoriously difficult to remove due to its chemical stability and resistance to degradation. The dual-functional MOF offers a scalable and field-deployable platform for effective PFAS remediation and monitoring.
The success of this approach also underscores the power of post-synthetic modification in MOF design, opening the door to the development of next-generation multifunctional materials with tailored performance for specific environmental contaminants.
About the Study
This research was conducted by a team led by Ling Zang, including Rana Dalapati and Ph.D. students Jiangfan Shi and Matthew Hunter. Their article, titled “Dual-Functional Metal-Organic Framework for Efficient Removal and Fluorescent Detection of Perfluorooctanoic Acid (PFOA) from Water,” was recently published in the Journal of Materials Chemistry C.
The research was supported by Gentex Corporation under a sponsored project, under award #10072348.