Monolith-Supported Amine-Functionalized Mg₂(dobpdc) Adsorbents for CO₂ Capture.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Metal-organic frameworks (MOFs) show promise for carbon dioxide (CO2) capture.
• Developing stable and scalable MOF-based adsorbents is crucial for industrial applications.
• Structured contactors offer advantages over traditional packed or fluidized beds for gas separations.

Purpose of the Study:

• To investigate the potential of amine-functionalized MOFs, specifically mmen-M2(dobpdc), for CO2 capture from simulated flue gas.
• To evaluate the stability and performance of MOFs supported on structured monoliths.
• To demonstrate a scalable approach for MOF adsorbent deployment.

Main Methods:

• Screening of mmen-M2(dobpdc) (M = Mg, Mn) for humidity stability using nitrogen physisorption and X-ray diffraction.
• Synthesis of mmen-Mg2(dobpdc) MOF films on α-alumina coated cordierite monoliths via MgO nanoparticle precursor and hydrothermal treatment.
• Assessment of CO2 adsorption capacity and cyclic performance using 10% CO2 in helium and 100% CO2.

Main Results:

• mmen-Mg2(dobpdc) exhibited superior stability under humid conditions compared to its manganese counterpart.
• A MOF film with good crystallite density and favorable crystal orientation was successfully synthesized on the monolith.
• The monolith-supported MOF demonstrated CO2 uptakes of 2.37 mmol/g (10% CO2) and 2.88 mmol/g (100% CO2).
• Excellent cyclic adsorption/desorption performance was observed over multiple cycles.

Conclusions:

• The amine-functionalized MOF, mmen-Mg2(dobpdc), is a promising candidate for CO2 capture applications.
• Supporting MOFs on structured monoliths provides a scalable and efficient platform for gas separations.
• This work represents a significant step towards the practical implementation of MOF adsorbents in industrial CO2 capture processes.