Comparison of MIL-101(Cr) metal-organic framework and 13X zeolite monoliths for CO2 capture

A comparative study was conducted to determine the pore properties and adsorptive performance of monoliths containing either the MIL-101(Cr) metal-organic framework or 13X zeolite for carbon dioxide (CO2) capture. Although there have been a great deal of previous work on CO2 adsorption onto zeolites and MOFs, there has been far fewer studies on structured adsorbents such as monoliths. The results indicate that MIL-101(Cr) monoliths have 1.3 times higher porosity than 13X zeolite monoliths. Increasing CO2 partial pressure in the gas mixture shortens breakthrough and equilibrium times and increases the breakthrough and equilibrium adsorption capacities of CO2. MIL-101(Cr) monoliths show better mass transfer of CO2 in the adsorbent bed with shorter breakthrough and equilibrium times of about 20% and 35%, respectively, than 13X zeolite monoliths. The adsorption capacity of CO2 on MIL-101(Cr) monoliths is higher by about 37% (based on weight in mmol/g) at breakthrough and slightly lower by about 7% at equilibrium when compared to 13X zeolite monoliths. MIL-101(Cr) monoliths were found to be 1.5 times more efficient for CO2 adsorption than 13X zeolite monoliths. The effects of regeneration temperature after CO2 adsorption on MIL-101(Cr) and 13X zeolite monoliths were studied and results showed an increase in CO2 adsorption capacity as the regeneration temperature was increased. In summary, the study showed MIL-101(Cr) monoliths have better CO2 adsorption properties than 13X zeolite monoliths.