In an industry-funded study published in the Journal of Materials Chemistry C, Ling Zang, professor in the John and Marcia Price College of Engineering’s Department of Materials Science and Engineering, and his team introduced a dual-functional metal-organic framework (MOF) known as UiO-66-N(CH₃)₃⁺, a zirconium-based material known for its thermal and chemical stability.
This new MOF is claimed to demonstrate exceptional capabilities in PFOA adsorption and fluorescence-based detection as the MOF 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.
According to the team, the MOF also exhibits admirable reusability, as tested through repeated adsorption–desorption cycles. After each adsorption, the material could be regenerated via washing.
“This MOF represents a major leap forward for PFAS remediation,” said Rana Dalapati, the study’s lead author and postdoctoral researcher in the Zang Research Group. “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.”
Useful but dangerous
PFOA is a synthetic chemical with water and stain-resistant properties and has commonly been used in non-stick pans, firefighting foam and other products. The material does not break down in the environment and has leached into groundwater, raising public health concerns. Consequently, detecting and mitigating PFOA and other PFAS contamination has become a priority for many environmental quality agencies.
Zang’s team constructed their MOF by modifying UiO-66-NH₂, another widely studied metal-organic framework recognised 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 limitation, the researchers incorporated quaternary ammonium groups that enhance electrostatic interactions with PFOA, resulting in a 3.4-fold increase in adsorption capacity compared to the parent UiO-66-NH₂ framework. These cationic groups also work synergistically with the MOF’s metal-binding sites, achieving high selectivity and efficiency in contaminant capture.
Key technological breakthroughs
The team said UiO-66-N(CH₃)₃⁺ achieves a maximum PFOA adsorption capacity of 1178mg/g, as determined by Langmuir isotherm modelling, which outperforms conventional sorbents such as activated carbon and unmodified MOFs.
Thanks to its highly porous, interconnected structure, the MOF removes nearly 100 per cent of PFOA from 50ppb aqueous solutions within five minutes, which is vital for real-world applications.
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.
Finally, the material maintains over 93 per cent adsorption capacity after five regeneration cycles, making it cost-effective and sustainable.
link