Water Bridges Substitute for Defects in Amine-Functionalized UiO-66, Boosting CO2 Adsorption

Arianjel F Hernandez; Rebekah K Impastato; Mohammad I Hossain; Brooks D Rabideau; T Grant Glover

doi:10.1021/acs.langmuir.1c01149

Water Bridges Substitute for Defects in Amine-Functionalized UiO-66, Boosting CO₂ Adsorption

Langmuir. 2021 Sep 7;37(35):10439-10449. doi: 10.1021/acs.langmuir.1c01149. Epub 2021 Aug 24.

Authors

Arianjel F Hernandez¹, Rebekah K Impastato¹, Mohammad I Hossain¹, Brooks D Rabideau¹, T Grant Glover¹

Affiliation

¹ Department of Chemical & Biomolecular Engineering, University of South Alabama, Mobile, Alabama 36688, United States.

PMID: 34427450
DOI: 10.1021/acs.langmuir.1c01149

Abstract

The binary adsorption of CO₂ and water on an amine-functionalized UiO-66 metal-organic framework (MOF) was studied experimentally and computationally. Grand canonical Monte Carlo simulations were used to investigate three additional UiO-66 MOFs with different functionalized linkers. Each MOF was studied in a defect-free form as well as two additional forms with precise linker defects. Binary adsorption isotherms are presented for CO₂ at specific water loadings. While water loading in defect-free MOFs reduces the CO₂ uptake, the defects slightly boost the CO₂ uptake at low water loadings. It was found that water bridges form between the metal oxide cores, replacing the missing linkers. Effectively, this creates smaller pores that are more welcoming of CO₂ adsorption. Experimental measurement of the binary isotherms for UiO-66-NH₂ shows a behavior that is consistent with this enhancement.