Abstract:
This study demonstrates that the synthesis of HMTA-modified Zn BDC and Ni BDC
metal-organic frameworks leads to materials exhibiting superior structural properties and
increased capacities for CO2 adsorption. The integration of HMTA enhances the surface
area and markedly improves the efficiency of these metal-organic frameworks (MOFs) in
CO2 capture, thereby establishing them as viable options for gas separation and
environmental remediation applications. The Zn BDC and Ni BDC metal-organic
frameworks (MOFs), along with their corresponding HMTA-modified variants, Zn
BDC⊃HMTA and Ni BDC⊃HMTA are prepared through hydrothermal method. The
synthesized metal-organic frameworks (MOFs) were characterized through a range of
analytical techniques, which encompassed X-ray diffraction (XRD), scanning electron
microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric
analysis (TGA), and Brunauer-Emmett-Teller (BET) analysis. The XRD and SEM
analysis demonstrated a crystal structure with notable morphological variations,
suggesting that the inclusion of HMTA transformed the structure from irregular
microspheres to interconnected sheets. The BET analysis revealed that the surface areas
for Zn BDC⊃HMTA and Ni BDC⊃HMTA were significantly enhanced, measuring 66.53
m²/g and 220.91 m²/g, respectively, in comparison to their non-HMTA counterparts. The
evaluation of CO2 adsorption capacities measured by utilizing a high-pressure gas sorption analyzer demonstrated that the HMTA-modified MOFs displayed enhanced CO2
adsorption properties, with Zn BDC⊃HMTA reaching a peak adsorption capacity of 3.50
mmol/g at 283 K, whereas Ni BDC⊃HMTA exhibited an adsorption capacity of 2.85
mmol/g. Both the values are higher than the unmodified BDC based MOFs. The results
underscore the efficacy of HMTA as a modifying linker, significantly improving both the
surface area and the adsorption capabilities of the metal-organic frameworks (MOFs).
