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Electric Swing Adsorption (ESA) is a separation process suitable for carbon dioxide (CO2) capture, but its implementation depends on the development of adsorbents combining good CO2 uptake and electrical conductivity. Here, we report the 3D printing of electrically conductive hybrid adsorbent structures made of zeolite 13X/activated carbon (Zeo-AC-3D) and zeolite 13X/graphite (Zeo-G-3D), but also of each individual precursor—Zeolite 13X (Zeo-3D), activated carbon (AC-3D), and graphite (G-3D). An extensive characterization of the materials by scanning electron microscopy, thermogravimetric analysis, mercury intrusion, and adsorption measurements is presented. The 3D printed structures have moderately smaller surface area and porosity than their precursor powders, with losses between 21% and 29% for Zeo-3D and Zeo-G-3D. The samples containing activated carbon present smaller losses (4–6%). All 3D printed structures exhibit a well-formed macroporous network with slightly larger pore diameter in the case of those generated from nonzeolitic precursors. The ordering of CO2 adsorption capacity of the 3D printed samples at 0.15 bar and 303 K is the following: Zeo-3D > Zeo-AC-3D > Zeo-G-3D > AC-3D > G-3D. At that pressure, the hybrid samples have CO2 working capacities of 1.03 mol/kg (Zeo-AC-3D) and 0.94 mol/kg (Zeo-G-3D) for adsorption at 303 K and desorption at 373 K. Zeo-G-3D is more efficiently heated by Joule effect than Zeo-AC-3D, attaining 343 K in 22 s under action of a 24 V voltage, while the latter only reaches 321 K (in 96 s). |
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