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 called “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 the drinking water. Among these substances, perfluorooctanoic acid (PFOA) is particularly prevalent. This study explores the application of a synthesized zirconium terephthalate (UiO-66) metal–organic framework (MOF) gel for highly efficient removal of PFOA from water. The UiO-66 gel maintains the structural stability of its powder form but also offers improved ease of handling. Structural characterization by Powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM) analyses revealed the gel's nanocrystalline structure (≈20 nm in size), which is 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 is confirmed by the detection of fluoride within the gel structure using Scanning Transmission Electron Microscopy-Energy Dispersive Spectroscopy (STEM-EDS) elemental mapping. In addition, to demonstrate the potential of membrane platforms as practical and scalable solutions for environmental remediation, the performance of an MOF gel filter is successfully tested.