Application of MOFs for treating PFAS in contaminated water : Removing and detecting PFAS using different ZIF, UiO and NU-1000 and its derivatives

Sammanfattning

Persistent organic pollutants (POP) are a huge global problem due to their accumulation in the environment and in living organisms, and one large subgroup of POPs is per- and polyfluoroalkyl substances (PFAS). There are conventional methods of removing and analyzing PFAS from water sources, but the problem is usually that they are inconvenient and costly. Metal-organic frameworks (MOFs) have been proposed as a solution to the problem. This study aims to investigate the capacity of nine different MOFs for removing and detecting PFAS. These nine MOFs consist of ZIF-7, ZIF-8, UiO-66, UiO-67, NU-1000, and four variants of these materials. The testing of their adsorption capacity showed that NU-1000 was the dominating candidate followed by UiO-67 and UiO-66. As for the detection of PFAS, the materials were incorporated into two systems of sensors consisting of electrochemical arrays and interdigitated electrodes. The electrochemical impedance spectroscopy measurements (EIS) of the latter showed uncertainty in the detection. However, the measurements from cyclic voltammetry, differential pulse voltammetry, and EIS of the arrays showed an increase in impedance when PFAS passivates the surface. The materials that performed excellently in the adsorption are especially worth further investing in and exploring to find the most suitable candidate of MOF for solving the challenge of treating PFAS in contaminated water.