Dimethylethanolamine-enhanced absorption and n-propanol-facilitated desorption: dual activation of an aminoethylethanolamine-based non-aqueous absorbent for high-efficiency reversible CO2 capture

Non-aqueous absorbents (NAAs) have emerged as promising candidates for CO 2 capture due to their energy-saving advantages and non-corrosive properties, yet necessitate further optimization in absorption capacity and regenerability for viable industrial implementation. This study developed a novel NAA through an innovative synergistic absorption–regeneration activation strategy, combining aminoethylethanolamine (AEEA) as the primary CO 2 -active component, 2-amino-2-methyl-1-propanol (AMP) to suppress insoluble products, with dimethylethanolamine (DMEA) and n-propanol (NPA) as dual-functional activators. Through coordinated activation mechanisms—DMEA-driven absorption enhancement and NPA-mediated regeneration promotion—the AEEA-AMP-DMEA-NPA (A-A-D-N) system achieved high-efficiency reversible CO 2 capture. Experimental optimization enabled A-A-D-N to obtain a CO 2 absorption loading of 1.51 mol·mol −1 (42.5 % higher than the DMEA-free system) and near-complete regeneration (≥98.13 %, 14.0 % improvement over the NPA-free system). The A-A-D-N formulation demonstrated exceptional cyclic stability, retaining the regeneration efficiency of 89.4 % after five consecutive absorption–desorption cycles. Mechanism studies combining 13 C NMR analysis and quantum chemical calculations revealed the dual-activation pathways: During absorption, DMEA facilitated zwitterion deprotonation and simultaneously regenerated active AEEA via AEEAH + deprotonation, enabling more AEEA to absorb CO 2 ; In regeneration, NPA acted as a proton shuttle through a low-energy-barrier relay mechanism, promoting efficient proton transfer from AEEAH + to AEEA-carbamate for carbamic acid formation, while subsequently catalyzing carbamic acid decomposition through proton exchange—a pathway distinct from conventional carbamate-to-carbonate conversion. Regeneration energy consumption analysis demonstrated A-A-D-N’s significant improvements over the benchmark 30 wt% MEA, with sensible heat and latent heat reduced by 76.1 % and 87.6 %, respectively. Furthermore, the A-A-D-N absorbent was verified to be non-corrosive to carbon steel. Overall, this work established a dual-activation strategy for developing novel NAAs with combined advantages of high-efficiency CO 2 capture capacity, energy savings and non-corrosive nature, thereby advancing CO 2 capture technologies.