Amine Sorbents for Sustainable Direct Air Capture: Long-Term Stability and Extended Aging Study
Bibliographic record
Abstract
The emerging technology of direct air capture (DAC) holds promise for the extraction of CO 2 from the air, offering a potential avenue to reverse climate change. However, DAC is still in its early stages of development, particularly on the sorbent material side, and the long-term stability of sorbents remains inadequately understood. This study investigates the impact of thermal degradation, hydrothermal treatment, long-term cyclic operation, and extended aging over 3 years on amine-supported sorbents and its effect on the adsorption capacity at DAC conditions. Sorbents were synthesized through various methods (impregnation, chemical grafting, and in situ polymerization) into two supports: large-pore AlMCM-41 (LPAlSi) and mesoporous silica foam (MSF). LPAlSi support demonstrates superior stability compared to MSF support under thermal and hydrothermal treatments. Impregnated sorbents with physically bonded amines exhibit the lowest stability, with a significant amine loss during all treatments, confirmed through porosity analysis, thermogravimetric analysis (TGA) decomposition, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). Additionally, they experience a notable 6% decrease in CO 2 uptake after 50 cycles. In contrast, chemically bonded amines through grafting and in situ polymerization display better stability due to stronger bonding, maintaining CO 2 uptake despite harsh treatments. In situ-polymerized sorbents into LPAlSi exhibit remarkable stability under thermal and hydrothermal treatments, experiencing drops of 17 and 27% over 3 days, respectively. Furthermore, they demonstrate outstanding stability over 50 cycles under DAC conditions, with only a 0.3% drop in CO 2 uptake. Extended aging of class III sorbent for 3 years indicates good stability in CO 2 uptake, with only an 11% drop compared to impregnated ones, which showed a larger decrease over a shorter time. The presented results suggest that in situ-polymerized amines into LPAlSi are promising materials for DAC, offering good capacity and significant long-term stability. With opportunities for further sorbent optimization, there is substantial potential to deploy DAC at a scalable level and mitigate global warming effects.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".