Research on CO2 Capture Performance and Absorption Mechanism of High-Load Biphasic Solvent TETA/1DMA2P

To achieve carbon peaking and carbon neutrality goals, the chemical absorption method is the most widely used and mature carbon capture technology. In this method, organic amine solution is a commonly used absorbent for CO₂ absorption. Biphasic solvents have been designed due to their significant advantages in reducing energy consumption for regeneration, and the development of new and efficient biphasic solvents has become the current research focus. The CO₂ absorption performance of absorbents with different ratios of triethylenetetramine (TETA) and 1-diethylamino-2-propanol (1DMA2P) was investigated by the bubbling absorption method, and it was found that the absorbent of 2 mol/L TETA + 2 mol/L 1DMA2P biphasic solvent showed the best performance. The volume of the rich phase after CO₂ absorption by the absorbent was 20% lower than that of the ethanolamine (MEA) solution, and the CO₂ absorption loading was as high as 0.656 mol CO₂/mol of total amine. The absorption temperature had little effect on absorption performance and the absorbent had a lower rich-phase volume and better absorption performance when the total amine concentration was 4 mol/L, and the optimum desorption temperature was 393.15 K. Meanwhile, the material composition was characterized by ¹³C NMR. It could be concluded that the biphasic solvent generated carbamate and protonated amine after absorbing CO₂, and the reaction product was mainly concentrated in the lower layer of the phase separation.