Synthesis, characterization, and CO2 breakthrough adsorption of a novel MWCNT/MIL-101(Cr) composite

Carbon dioxide is quantitatively the most significant component which facilitates in the global warming, it is utmost necessary to suppress the rapid increase of CO2 concentration in the atmosphere by means of Carbon Capture and Storage (CCS). Metal-organic framework (MOF) MOFs has recently been developed with the primary objective of CO2 capture from flue gases with minimum energy penalties. MIL-101(Cr) holds the supreme importance amongst such types of MOFs owing to its extraordinary thermal and hydro stability. In this study, a novel composite composed of multi-walled carbon nanotubes (MWCNTs) incorporated in a MIL-101(Cr) framework has been synthesized using a molecular-level mixing process in order to enhance the thermal properties of the base framework as well as augment the CO2 adsorption capacity and separation. The synthesized and activated MWCNT/MIL-101(Cr) composites have been characterized for degree of crystallinity, microstructure, thermal stability, and CO2 and N-2 equilibrium adsorption capacity. Actual dynamic behavior of adsorption breakthrough tests have been conducted under ambient conditions (297 K and 101.325 kPa) to address the real adsorptive behavior and to quantify the level of the CO2 adsorption capacity and breakpoint enhancements. Results demonstrate that a substantial improvement in the CO2 adsorption capacity and breakpoint over pristine MIL-101(Cr) is achievable with the 2 wt% MWCNT/MIL-101(Cr) composite with measured optimal enhancements of about 35.94% and 32.11%, respectively.