Hierarchically Porous Mg-MOF-74/Sodium Alginate Composite Aerogel for CO2 Capture

One of the most promising methods for capturing carbon dioxide (CO 2 ) is solid physical adsorption, which is an efficient and simple technique. The key to effective CO 2 capture is the development of high-performance solid adsorbents with excellent CO 2 adsorption capacity, CO 2 /N 2 selectivity, and rapid adsorption/desorption kinetics. In this paper, a Mg-MOF-74/sodium alginate composite aerogel was prepared by loading Mg-MOF-74 on sodium alginate sheets followed by directional freeze-drying. The composite aerogel exhibited a hierarchical porous structure, in which sodium alginate provided an open mesoporous/macroporous structure that promoted diffusion and contact with the active center of CO 2 . The Mg-MOF-74 micropores/mesopores promoted the strong interaction between CO 2 and the adsorbent in the micropore and rapid mass transfer of CO 2 to the adsorbent through the mesopores. The experimental data showed that MSA-6 achieved CO 2 adsorption of 2.461 mmol·g –1 at 298 K. Furthermore, the CO 2 /N 2 adsorption selectivity of MSA-6 reached 35.108, indicating its strong CO 2 selective adsorption potential.