Structure-Performance Relationships in Zirconium-Based MOF Sponge Composites for Single- and Mixed-PFAS Removal from Aqueous Systems

The prevalence of per- and polyfluoroalkyl substances (PFASs) in drinking water necessitates the development of rapid, scalable remediation technologies. This study reports the synthesis and evaluation of metal–organic framework@polypropylene (MOF@PP) sponge composites for the sequestration of four representative PFAS analytes. We investigate the influence of MOF architecture by comparing three Zr-based frameworks, MOF-808, NU-1000, and UiO-66, integrated into a porous sponge matrix. Testing in multicomponent PFAS solutions revealed that PP@NU-1000 is a superior adsorbent, removing ∼60% of both short- and long-chain PFAS within 30 min and >80% after 1 day. Notably, isothermal titration calorimetry (ITC) and kinetic fitting suggest that the adsorption mechanism primarily involves physisorption which is largely restricted by smaller pore apertures and intraparticle diffusion. Compared with NU-1000, MOF-808 and UiO-66 showed lower and more selective uptake, consistent with stronger pore-access and intraparticle-diffusion limitations. Furthermore, the composites demonstrate recyclability through ethanol washing, while salt and mild acid treatments showed limited efficacy. These findings highlight the potential of MOF-functionalized sponges as high-performance, regenerable materials for sustainable water treatment over extended time scales.