https://doi.org/10.3390/en15093473
“The UiO-66 (UiO = University of Oslo) class involves Zr6O4(OH)4 octahedral nodes that form latices in an ideal 12-fold co-ordination with dicarboxylic linkers resulting in a cubic, close-packed unit cell structure. To date, CO2 capture capacities for UiO-66 with incorporated functionalities have been relatively extensively studied. In addition, the range of functionality is extremely wide, including amine, alkyl, acid, hydroxy functionalized UiO-66 composites, metal-exchange functionalized UiO-66, and others. According to review by Usman et al. [31], CO2 capacity of mentioned materials varies from 2.7 wt% (UiO-66-(COOK)4-EX, 298 K) to 25.6 wt% (UiO-66-(CH3)2, 273 K). The MOFs of UiO-66 class are characterized by excellent chemical, thermal and mechanical properties [32]. Moreover, UiO-66(Zr)-COOH)2 are considered to be very stable with high selectivity for CO2/N2 separation, high working capacity, and efficient recyclability [33]. Studies published by other authors confirm the selectivity of this Zr-containing MOF, indicating that UiO-66(Zr)-(COOH)2 has the highest CO2 adsorption capacity compared to other studied gases (CH4, N2, CO, and H2). The amount of CO2 adsorbed at 303 K, 0.99 bar reaches 1.05 mmol/g [34]. One of the most important limiting factors for the effective practical use of all MOFs studied is their processability due to their inherent powdery nature.”