Carbon capture and sequestration (CCS) from fossil fuel-fired power plants is a key strategy to reduce global anthropogenic CO2 emissions. Recently, diamine-appended variants of the metal-organic framework Mg2(dobpdc) (dobpdc4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) have emerged as a promising class of adsorbents for carbon capture applications because they display step-shaped CO2 adsorption profiles, which enable high working capacities to be achieved with minimal temperature swings. This talk will focus on two promising directions for these materials. First, a diaminopropane-appended framework has been identified that enables &gt;90% capture from humid coal flue gas streams and is stable over 1000 adsorption/desorption cycles. This adsorbent enables high working capacities (2.5 mmol/g) with only a 60 °C temperature swing. Solid-state NMR and X-ray diffraction experiments confirm that this diaminopropane-appended framework operates by an adsorption mechanism involving both ammonium carbamates and carbamic acid pairs, the latter crystallographically verified in a porous material for the first time. Second, frameworks appended with primary,secondary diamines are promising for CO2 capture from the emissions of natural gas-fired power plants owing to their low CO2 adsorption step pressures (&lt;1 mbar at 40 °C) and high thermal stability. In particular, a cyclic ethylenediamine-appended variant of Mg2(dobpdc) shows exceptional performance for this capture process in humid breakthrough and cycling experiments.

Diamine-appended metal-organic frameworks for carbon dioxide capture from fossil fuel-fired power plants

255th National Meeting (2018)

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