(193a) Low Cost CO2 Adsorbents with High CO2-Over-N2 Selectivity

Fossil fuel contributes to 81% of the world's commercial energy supply and combustion of fossil fuel trigger severe global warming. In order to stabilize the level of CO2 in the atmosphere Carbon Capture and Storage should be rapidly introduced. However, the cost for carbon capture is very high and it is urgent to reduce this cost significantly. Adsorption-driven carbon capture, such as pressure/vacuum swing adsorption (PSA/VPSA), temperature swing adsorption (TSA) and electrical swing adsorption (ESA) have attracted much attention because of their low energy cost and environmental friendly characteristics. The adsorbents are central to their function and cost. Here, we present a recently developed low-cost CO2 adsorbents with very high CO2-over-N2 selectivities. The CO2 and N2 adsorption isotherms were measured for these zeolite NaKA at different K+ contents and different temperatures. The study showed that the CO2-over-N2 on the best NaKA with 17 at. % K+ content can reach 172 with CO2 uptake of 3.43 mmol/g (0.85 bar, 298K). A self-consistent and molecular rational for the selectivity could be using in-situ IR spectroscopy, X-ray diffraction, molecular simulations, in addition to the adsorption experiments. The results indicate that zeolite NaKA with mixed cations is a good adsorbent for the separation of CO2 from water-free flue gases using PSA techniques and could potentially be used as the second step in a two-staged adsorption driven capture of carbon dioxide.