Toward Sustainable Metal-Organic Frameworks for Post-Combustion Carbon Capture by Life Cycle Assessment and Molecular Simulation

Metal-organic frameworks (MOFs), an emerging class of materials, have been regarded as highly promising adsorbent materials for carbon capture and sequestration (CCS). To date, most reported studies have mainly focused on evaluating MOF candidates based on their adsorption properties (e.g., selectivity) or their performance using a process model. The overall environmental impact of this emerging new class of materials remains unknown. Several aspects, including the energy load and resource depletion from the MOF production process as well as other steps in the life cycle system of MOF-based CCS, should also be considered. Herein, we assess the impact of a diverse set of approximately 50 MOFs for CCS via life cycle assessment and molecular simulation. Our results identify that, aside from the impact imposed by the CO2 separation process, the use of solvents (i.e., type and amount) in the MOF production process plays a critical role. Particularly, for environmental impacts such as the eutrophication potential, solvent use can be the most significant contributor. Seeking greener alternatives (e.g., methanol and water) and improving their recycle rates are therefore essential. Comparing with the monoethanolamine scrubbing technology, we have also identified several promising structures in this study. The outcomes of this study are instrumental to the future development of novel porous materials.