An investigation on the effects of organic additives on CO2 capture performance of Na2CO3 solution

BACKGROUND: The large-scale practical application of CO2 capture using carbonate solutions is mainly limited by their low CO2 absorption rate. In view of this, it is feasible to improve CO2 capture performance of carbonate solution by adding additives. In this paper, low-cost sodium carbonate (Na2CO3) solution was selected as the main CO2 absorbent, and the effects of different organic additives on CO2 capture performance of Na2CO3 solutions were systematically investigated.RESULTS: The results showed that 0.04 mol/L tetrabutylammonium bromide (TBAB) could achieve a better enhancement effect on CO2 capture performance of Na2CO3 solution. After addition of TBAB, the maximum CO2 absorption rate of Na2CO3 solution was improved to 2.52 x 10(-3) mol/min, which increased by 105%. And the maximum CO2 desorption rate could also be improved by 45%. TBAB/Na2CO3 system not only realized a high CO2 absorption capacity of 0.769 mol/mol, but also maintained 82% of the initial CO2 absorption capacity after three cyclic tests. The regeneration heat duty of TBAB/Na2CO3 solution was calculated to be 1136.6 kJ/mol, which was significantly lower than that of single Na2CO3 solution and conventional MEA aqueous solution. The promotion mechanism of TBAB in Na2CO3 solution was explored using Fourier transform infrared spectra (FTIR) and C-13 nuclear magnetic resonance (NMR) analysis.CONCLUSION: The introduction of TBAB additive could significantly improve CO2 capture performance of Na2CO3 solution and reduce regeneration heat duty, making it a possible option in the field of post-combustion CO2 capture. (c) 2023 Society of Chemical Industry (SCI).