Highly Efficient Removal of Perfluorooctanoic Acid from Water using Zirconium Terephthalate (UiO-66) Gel

The extensive use and environmental release of perfluoroalkyl substances (PFAS), often referred to as “forever chemicals”, has raised significant health and environmental concerns. Due to their persistence and resistance to natural degradation, PFAS appear in concerningly high concentrations, e.g., in our drinking water. Among these substances, perfluorooctanoic acid (PFOA) is particularly prevalent. This study explores the application of synthesized zirconium terephthalate (UiO-66) metal-organic framework (MOF) gel for highly efficient removal of PFOA from water. The UiO-66 gel not only maintains the structural stability of its powder form but also offers improved ease of handling. Structural characterization by PXRD and TEM analyses revealed the gel's nanocrystalline structure (~20 nm in size), which was further confirmed by electron diffraction. Quantitative NMR spectroscopy demonstrated a PFOA removal efficiency of 96%. The successful absorption of the polyfluoro compound into the UiO-66 gel after filtration was confirmed by the detection of fluoride within the gel structure using STEM-EDS elemental mapping. In addition, to demonstrate the potential of developing membrane platforms as practical and scalable solutions for environmental remediation, the performance of a MOF gel filter was successfully tested.