• Phosphonate MOFs
• adsorption
• Materials

This thesis work focuses on the grafting of diamines on the internal surface of metal-organic frameworks (MOFs) and the ability of these systems to adsorb CO2. Phosphonate-based MOFs -STA-12 and STA-16 (Ni, Co)- were post-synthetically functionalized with different alkyldiamines (ethylenediamine, N,N-diethylethylenediamine and N,N’-dimethylethylenediamine) and characterized by combining different techniques (powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, nuclear magnetic resonance spectroscopy). As expected, the diamine loading trend observed for these materials decreased as the pore size decreased and the steric hindrance of the diamine increased.
The adsorption properties were evaluated by gas sorption analysis, registering N2 (77 K) and CO2 (298 K) isotherms. All the tested materials showed Langmuir-type isotherms. The introduction of the diamines significantly affected the accessible pore volume, leading to smaller CO2 adsorption capacities than in the pristine MOFs.