What question did this study set out to answer?

This work aims to integrate direct air capture with CO2 mineralisation using potassium salts of glycine and alanines.

April 27, 2026Journal of environmental chemical engineering0 citationsOpen Access

Towards the Integration of Direct Air Capture and CO2 Mineralisation Processes Employing Potassium Glycinate, and α- and β- Alaninate

SLSofia Lazareva NMNouman Mirza DFDebra Fernandes

Key Points

This work aims to integrate direct air capture with CO2 mineralisation using potassium salts of glycine and alanines.
Studied three potassium salts: potassium glycinate, α-alanine, and β-alanine in CO2 absorption and mineralisation.
Measured mass transfer coefficients of CO2 concentrations from 200 to 800 ppm using a wetted wall column.
Analyzed solid products using powder X-ray diffraction and Fourier transform infrared spectroscopy.
The potassium salt of α-alanine achieved approximately 60% CO2 removal using CaO after 50 minutes.
Improved mineralisation with bicarbonate species formation observed in CO2-loaded amino acid salt solutions.
High purity calcite (CaCO3) obtained from solutions after 7 days post-mineralisation.

Abstract

In the present work, three potassium salts of glycine, α-alanine and β-alanine were studied for an integrated direct air capture (DAC) – CO 2 mineralisation process. The influence of steric hindrance in amino acid (AA) salt solutions on mineralisation of absorbed CO 2 was investigated by employing CaO and MgO as the CO 2 mineralising agents. The overall mass transfer coefficients (K ov ) for DAC concentrations (200 – 800 ppm) of CO 2 were measured using a wetted wall column (WWC) with partial regeneration of the absorbents observed after mineralisation with MgO. An improved mineralisation was evidenced by the formation of bicarbonate species in CO 2 -loaded AA salt solutions, supported by nuclear magnetic resonance (NMR) analysis. When CaO was used as the mineralising agent, the sterically hindered potassium salt of α-alanine solution resulted in the highest CO 2 removal (approximately 60%) after 50 min of reaction and filtration. Solid products of mineralisation reactions were analysed using powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). High purity calcite (CaCO 3 ) was obtained for the solutions stored for 7 days after the mineralisation reaction. • Potassium (K) glycinate, K-α- and K-β-alaninate are used as absorbents for DAC. • Absorbents are studied for DAC and subsequent regeneration by CO 2 mineralization. • Higher (bi)carbonate species are produced for K-α-alaninate with steric hindrance. • K-α-alaninate is regenerated using CO 2 mineralisation by Ca- and Mg-oxides.

KI fragen

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