Metal-organic cages (MOCs) are formed from the multicomponent assembly of appropriate ligands (L) and metal ions (M); when used to form well-defined junctions in polymer networks, MOCs of high branch functionality provide polyMOC gels with relatively high shear modulus despite a high fraction of loop defects. The substitution of inelastic loop defects with functional free ligands at little to no cost to the modulus provides a route for polyMOC gels to be used in practical applications. By using different endo- and exo-functionalized free ligands, this material can be tailored to adsorb multiple water pollutants with high specificity. Our modular system uses telechelic tetra-arm poly(ethylene glycol) (PEG) end-functionalized with M12L24-forming bispyridine ligands and is self-assembled with platinum salt, which provides a robust gel that can withstand up to 12 wash and reuse cycles. Preliminary results demonstrate that free ligands functionalized with fluorinated alkyl groups produce polyMOC gels able to adsorb model compound perfluorooctanoic acid (PFOA) at 95% efficiency that can be washed and regenerated for reuse.