(304b) Experimental Characterization of Sorbents for Direct Air Capture of Carbon Dioxide | AIChE

(304b) Experimental Characterization of Sorbents for Direct Air Capture of Carbon Dioxide


Lackner, K. S., Arizona State University
Cirucci, J. F., Arizona State University
Green, M. D., Arizona State University
Direct air capture (DAC) technology is an unprecedented and important solution to climate change. Even if we reduced CO2 emissions to zero in a relatively short period of time, we will still need to remove 1,000 gigatons of CO2 from the atmosphere by the end of the century to prevent the planet from warming above 1.5 ËšC1. Temperature, pressure, and moisture swing DAC processes are amenable to a range of advanced sorbents which promote efficient CO2 sorption and regeneration2,3. The development, selection, and application of appropriate sorbents require a full understanding of essential characteristics during both sorption and desorption: 1) reaction kinetics; 2) mass transfer; 3) heat transfer; 4) equilibrium capacity; 5) cyclability (lifetime). The definition of these characteristics enables the development, design and scale-up of system processes and equipment to attain technical and economic feasibility4. There are numerous candidate materials with potential for DAC, each can be used in a variety of process cycles or regional climates. We have developed a systematic approach to evaluate sorbents from the milligram to tonne scale considering the important parameters mentioned above. Our systems comprise 1) a closed system (150 mL total volume) for fast screening of sorbents in the 1-10 mg scale; 2) an open flow system to test 0.1-1 g scale; 3) a wind tunnel system to test 1-100 g scale under representative air flow velocities and with appropriate form factor; 4) a bench scale reactor to test 0.1-2 kg scale; 5) and finally, our mechanical tree prototype which will be able to test at the 0.1-1 tonne scale. We will describe those systems and provided relevant results for representative sorbents which demonstrate favorable rate and capacity characteristics.


  1. Intergovernmental Panel on Climate Change (IPCC). Special Report Global Warming of 1.5 C°, Available at: <www.ipcc.ch>
  2. Tao Wang; Klaus S. Lackner; and Allen B. Wright. Moisture-swing sorption for carbon dioxide capture from ambient air: a thermodynamic analysis. Phys. Chem. Chem. Phys., 2013, 15, 504.
  3. Xiaoyang Shi; Hang Xiao; Habib Azarabadi; Juzheng Song; Xiaolong Wu; Xi Chen; and Klaus S. Lackner. Sorbents for the Direct Capture of CO2 from Ambient Air. Chem. Int. Ed. 2020, 59,6984 –7006
  4. Habib Azarabadi; Klaus S. Lackner. A sorbent-focused techno-economic analysis of direct air capture. Applied Energy 250 (2019) 959–975.