Surface tunable magnetic nano-sorbents for carbon dioxide sorption and separation

•Magnetic, surface tunable nano-sorbents were prepared from commercially available materials.•Polyethylenimine coated nano-sorbents exhibit both high CO2 sorption capacity and selectivity.•As prepared, nano-sorbents show excellent recyclability.

The increasing level of carbon dioxide (CO2) in the atmosphere is directly linked to global climate change, which has motivated a number of technological-based mitigation approaches for carbon capture and storage. Among these, CO2 sorption using solid sorbents is one of the most promising strategies. This report focuses on the development and evaluation of novel, hybrid inorganic-organic magnetic nano-sorbents for advanced, high capacity CO2 sorption and magnetic separation processes. Magnetic nanocomposites were prepared by grafting various polymers (e.g. polyethylenimine, polyethylene glycol, etc.) onto magnetite nanoparticles (nMAG) through solution-based sonication and evaporation methodologies. Further, we demonstrate that nMAG can be coated with polyethylenimine (PEI) with different molecular weights (Mw) and structures (linear vs. branched), yielding nMAG nanocomposite libraries with varied PEI loadings and combinations of amine types (primary, secondary, and tertiary amines). Surface functionalized nMAG nanocomposites were characterized by TEM, BET, SQUID, and FTIR techniques and evaluated for CO2 adsorption capacity and recyclability with TGA. Among the as-prepared materials, PEI-nMAG shows the highest CO2 adsorption capacity with superior selectivity and recyclability.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (112 K)Download as PowerPoint slide