Carbon capture using adsorption processes can significantly mitigate global warming. Mg-MOF-74 is a distinct reticularmaterial amongst other adsorbents owing to its distinguished carbon dioxide adsorption capacity and selectivity under lowpressureapplications, while MIL-100(Fe) has lower CO2adsorption capacity, but extraordinary thermal and hydrostabilityin comparison to many classes of MOFs. In this paper, we present CO2adsorption characteristics of new compounds formedby the incorporation of multi-walled carbon nanotubes (mwcnts) into Mg-MOF-74 and MIL-100(Fe). This was done toimprove the thermal diffusion properties of the base MOFs to enhance their adsorption capacities. The new compositeshave been characterized for degree of crystallinity, and the CO2and N2equilibrium uptake. The real adsorption separationhas been investigated by dynamic breakthrough tests at 297 K and 101. 325. The equilibrium isotherm results showed thatMg-MOF-74 and 0. 25 wt% mwcnt/MIL-100(Fe) (MMC2) have the highest CO2uptake in comparison to the other investigatedcomposites. However, the interesting results obtained from breakthrough tests demonstrate that good improvementsin the CO2adsorption uptake and breakthrough breakpoint over pristine Mg-MOF-74 have been accomplished by adding 1. 5wt% mwcnt to Mg-MOF-74. The improvements of CO2adsorption capacity and breakpoint were about 7. 35 and 8. 03%, respectively. Similarly, the CO2adsorption uptake and breakthrough breakpoint over pristine MIL-100(Fe) are obtained by0. 1 wt% mwcnt/MIL-100(Fe) (MMC1) with improvements of 12. 02 and 9. 21%, respectively.