Work

Direct Air Capture: Recyclability and Exceptional CO 2 Uptake Using a Superbase

Year: 2025

Type: article

Abstract: Direct air capture (DAC) of CO 2 presents challenges owing to its low concentration and the high humidity of ambient air. In this study, efficient and reversible CO 2 capture from humid air was achieved using a liquid absorbent derived from a deep eutectic solvent (DES), composed of 1,5,7-triazabicyclo [4.3.0] non-6-ene (TBN) and benzyl alcohol. Unlike conventional superbases, TBN-containing DES exhibits an exceptional absorption capacity of 0.154 g CO 2 /g DES (3.5 mmol/g, 1.25 mol/mol) from untreated ambient air (humidity above 90%). The DES underwent 100 absorption–desorption cycles, retaining 74% of its CO 2 capture capacity after 50 cycles and 50% after 100 cycles. High stability, low toxicity, very high capture capacity, recyclability, and moisture insensitivity characterize this outstanding sorbent, making it suitable for DAC. This absorbent desorbs CO 2 at just 70 °C within 30 min, effectively addressing one of the most challenging steps in DAC. According to the literature survey, this unique DES outperforms all previously reported liquid absorbents for DAC in terms of recyclability, efficiency, and practicality.

Source: Environmental Science & Technology

DOI: 10.1021/acs.est.5c13908

Authors: Zahra Eshaghi Gorji, Baljeet Singh, Antti Lempinen, Timo Repo

Institution: University of Helsinki

Language: English

Topic: Carbon Dioxide Capture Technologies

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Climate action, Responsible consumption and production, Affordable and clean energy

Open Access status: green

Funders: Magnus Ehrnroothin Säätiö, Business Finland