1 research outputs found
Understanding the Adsorption of PFOA on MIL-101(Cr)-Based Anionic-Exchange Metal–Organic Frameworks: Comparing DFT Calculations with Aqueous Sorption Experiments
To examine the effects of different
functionalization methods on adsorption behavior, anionic-exchange
MIL-101Â(Cr) metal–organic frameworks (MOFs) were synthesized
using preassembled modification (PAM) and postsynthetic modification
(PSM) methods. Perfluorooctanoic acid (PFOA) adsorption results indicated
that the maximum PFOA adsorption capacity was 1.19 and 1.89 mmol g<sup>–1</sup> for anionic-exchange MIL-101Â(Cr) prepared by PAM
and PSM, respectively. The sorption equilibrium was rapidly reached
within 60 min. Our results indicated that PSM is a better modification
technique for introducing functional groups onto MOFs for adsorptive
removal because PAM places functional groups onto the aperture of
the nanopore, which hinders the entrance of organic contaminants.
Our experimental results and the results of complementary density
functional theory calculations revealed that in addition to the anion-exchange
mechanism, the major PFOA adsorption mechanism is a combination of
Lewis acid/base complexation between PFOA and CrÂ(III) and electrostatic
interaction between PFOA and the protonated carboxyl groups of the
bdc (terephthalic acid) linker