A fluorinated zirconium-based metal-organic framework as a platform for the capture and removal of perfluorinated pollutants from air and water

Abstract

A series of zirconium-based MOFs with acclaimed stability was prepared and their ability to adsorb polyfluorinated pollutants was compared. A novel fluorinated UiO-67 analogue, named UiO-67-F2, was synthesised alongside three previously reported materials, namely UiO-67-NH2, UiO-68-(CF3)2, and UiO-67. The structures were established and confirmed by powder X-ray diffraction. UiO-67-NH2, UiO-68(CF3)2 and UiO-67-F2 were examined as sorbents for the perfluorinated gas, sulphur hexafluoride (SF6) from the gaseous phase. The SF6 uptake of UiO-67-NH2 and UiO-67-F2 at 100 kPa, 20 °C, was high (5.54 and 5.24 mmol g−1, respectively). Furthermore, UiO-67-F2 exhibited a remarkable PFOA uptake of 928 mgPFOA per gMOF in an aqueous solution, which far exceeded that of unmodified UiO-67 (872 mgPFOA per gMOF at 1000 mgPFOA per LWater). This study has identified strengths and potential applications of the novel UiO-67-F2, as well as the impact of fluorine functionalization. It also offers some insight into the structure-property relations of UiO-based MOFs for their use as low-pressure SF6 storage materials and PFAS sorbents intended for water purification under ambient conditions.