Dative post synthetic methods on SBUs of MWCNT@MOFs hybrid composite and its effect on CO2 uptake properties

Two hybrid materials composed of metal-organic framework (MIL-100(Cr) and Cu-3(BTC)(2)) and carboxyl-modified multi-wall carbon nanotubes (MWCNTs) were synthesized successfully in situ and characterized by nitrogen adsorption-desorption isotherms, X-Ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) and Scanning Electron Microscopy (SEM). The gas adsorption properties of both of these hybrid materials were compared to the pristine MIL-100(Cr) and Cu-3(BTC)(2) materials. Carbon dioxide adsorption capacity is increased about 64% and 76% (from 5.8 to 9.52 mmol g-1 and from 4.53 to 8 mmol g-1) respectively at 298 K and 18 bar. The increment in the CO2 adsorption capacity of composite is attributed to the increase of micropore volume of MIL100( Cr) and Cu-3(BTC)(2) by MWCNT incorporation. Then frameworks of CNT@Cu-3(BTC)(2)-En and CNT@MIL100( Cr)-En (En = ethylenediamine) were functionalized with the primary amine via post modification. It was found that CNT@Cu-3(BTC)(2)-En (4.7 mmol g(-1)) shows a higher adsorption capacity for acidic gas as compared to CNT@ MIL-100(Cr)-En (3.7 mmol g(-1)) at 298 K and 1 bar.