Effect of functional groups in MIL-101 on water sorption behavior

Four MIL-101-type porous coordination polymers were synthesized containing different substituents (–H, –NO2, –NH2, –SO3H) in the ligand and their water sorption properties were investigated. All of the compounds adsorbed huge amounts of water (ca. 0.8–1.2 g g−1) and the adsorbed water can be released at relatively low temperatures (ca. 353 K). In addition, the trapping pressure of water adsorption was found to be controlled by changing the substituents, varying the hydrophobicity of the functional groups.

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► MIL-101 with different functionalities (–H, –NO2, –NH2, –SO3H).
► Huge capacity of nanopores for water adsorption.
► Water sorption pressures were modulated by functional groups on the pore surface.