Study of CO₂ absorption by cement paste containing amine compounds: a comparative study of diethylamine, dimethylamine and isopropylamine

The immobilization of carbon dioxide (CO₂) using mineral carbonation technology is a promising approach for mitigating greenhouse gas emissions. This study investigated the enhancement of the CO₂ absorption properties of cement pastes by employing various amine compounds such as diethylamine (DEA), dimethylamine (DMA), and isopropylamine (IPA). Systematic investigations were also carried out by incorporating the optimum concentrations of amine: 1%, 2%, and 3% for DEA, DMA, and IPA, respectively. Accelerated carbonation tests were conducted to evaluate the CO₂ absorption characteristics and TGA–DSC and XRD analyses were performed to characterize the structural properties of the materials. The results indicated that the cement paste with amine additives exhibited higher CO₂ absorption rates than those of the pristine cement paste. Notably, DMA demonstrated the most effective uptake with increasing amine concentration, achieving a 2.3 times faster absorption rate than the plain cement paste at 3% concentration. TGA–DSC analyses revealed a reduction in the calcium hydroxide content from 9.0 to 8.6% and an increase in the calcium carbonate content from 2.0 to 3.4% in the amine-added cement pastes. XRD analyses confirmed enhanced crystallinity with CO₂ absorption, particularly with DMA exhibiting peak intensity increases of up to 40% compared to the control samples. This investigation indicates that amine-enhanced cement paste demonstrates effective CO₂ absorption properties and has potential applications in environmental mitigation strategies and sustainable construction materials.