Low-Temperature Desorption of CO2 from Carbamic Acid for CO2 Condensation by Direct Air Capture

Furong Cao; Soichi Kikkawa; Hidetaka Yamada; Hideyuki Kawasoko; Seiji Yamazoe

doi:10.1021/acsomega.4c05978

Low-Temperature Desorption of CO₂ from Carbamic Acid for CO₂ Condensation by Direct Air Capture

ACS Omega. 2024 Sep 13;9(38):40075-40081. doi: 10.1021/acsomega.4c05978. eCollection 2024 Sep 24.

Authors

Furong Cao¹, Soichi Kikkawa¹, Hidetaka Yamada², Hideyuki Kawasoko^{1

3}, Seiji Yamazoe¹

Affiliations

¹ Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan.
² Frontier Science and Social Co-creation Initiative, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
³ Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Tokyo 102-0076, Japan.

Abstract

The high temperature requirement for the desorption of absorbed CO₂ is one of the issues for the widespread use of direct air capture (DAC), which is a promising technology to reduce atmospheric CO₂ concentration. This work realized a liquid diamine absorbent-solid carbamic acid (CA) phase-change DAC system with CO₂ desorption at a low temperature by using a MeOH solvent. The CA of isophoronediamine [3-(aminomethyl)-3,5,5-trimethylcyclohexylamine, CA-IPDA] readily desorbed CO₂ in MeOH at 50 °C, while IPDA showed the capacity to absorb low-concentration CO₂ from air with an IPDA/CO₂ ratio of 1:1. The CA-IPDA desorbed more than half of the absorbed CO₂ at 60 °C without any gas flow, proving that this system can condense low-concentration CO₂ in air to pure CO₂ with low energy requirements. The low-temperature desorption of CO₂ from CA-IPDA was owing to the high solubility of CA-IPDA in MeOH and the easy CO₂ transfer between carbamic acid and MeOH to form methyl carbonate ions. This solubility control in the liquid-solid phase-change system opens up the low-energy DAC systems.