(374h) Electrospun Polymer Fibers for Carbon Capture of CO2

Carbon capture in ambient air, known as direct air capture (DAC), is increasingly required to meet global climate goals. To improve DAC systems, more cheap and effective adsorbents need to be designed [1]. Branched polyethylenimine (PEI) is a networked polymer with primary, secondary, and tertiary amine groups known to be a good carbon capture material [2]. We hypothesize that electrospinning PEI and polystyrene (PS) will improve CO₂ adsorption capacity and rate, as electrospinning increases the surface area of the polymer scaffold [3]. PS is added to improve the strength and overall fiber morphology when co-spun with PEI. For a PEI/ PS mixture, the best electrospinning parameters were at 15 cm needle-to-drum distance, 1 mL/hour ejection rate, 1.5 V drum rotation voltage, and 15 kV for primary electrospinning voltage. CO₂ adsorption performance was measured with isothermal thermogravimetric analysis (TGA) over temperatures ranging between 30°C to 90°C. Varying weight percentages of PEI/PS from 0 wt% to 30 wt% PEI:PS had the highest adsorption capacity when spun at 20 wt% PEI:PS. At 20 wt% PEI:PS, the adsorption capacity was determined to be 0.97 mmol/g at 50°C with a maximum adsorption rate of 0.57 mmol/g/min. The maximum desorption rate of 0.14 mmol/g/min was found to be 4 times slower that adsorption. The results of this study will help improve the development of energy efficient and cheaper DAC technologies.

[1] International Energy Agency IEA, Direct Air Capture. 2021, Paris https://www.iea.org/reports/direct-air-capture

[2] X. Shen, H. Du, R. H. Mullins, R. R. Kommalapati, Polyethylenimine Applications in Carbon Dioxide Capture and Separation: From Theoretical Study to Experimental Work. Energy Technol. 2017(5) 822. doi:10.1002/ente.201600694

[3] C. Huang, P. Wang, Y. Li Fabrication of electrospun CO2 adsorption membrane for zinc-air battery application, Chem Eng J. 2020 395. doi:10.1016/j.cej.2020.125031