Absorption of CO₂ into Aqueous Potassium Salt Solutions of <small>l</small>-Alanine and <small>l</small>-Proline

다국어 초록 (Multilingual Abstract)

<P>Aqueous potassium salt solutions of <SMALL>l</SMALL>-alanine and <SMALL>l</SMALL>-proline were investigated as carbon dioxide (CO<SUB>2</SUB>) absorbents. The CO<SUB>2</SUB> absorption capacities and absorption heats (−Δ<I>H</I><SUB>abs</SUB>) of the aqueous amino acid salts were measured in a semi-batch absorption system and differential reaction calorimeter (DRC). The solution experiments tested concentrations of 2.5 M and were carried out at 298 and 313 K. The <SUP>13</SUP>C and <SUP>1</SUP>H nuclear magnetic resonance (NMR) spectra were used to identify the species distributions in the CO<SUB>2</SUB>-loaded absorbents. The absorption properties were compared to those of the commercial monoethanolamine (MEA) absorbent, revealing that the CO<SUB>2</SUB> loading capacity was higher than that of MEA (0.68 mol of CO<SUB>2</SUB>/mol of solute for the potassium salt of <SMALL>l</SMALL>-alanine > 0.5 mol of CO<SUB>2</SUB>/mol of solute for MEA). The absorption heat was lower than that of MEA at 298 K (53.26 kJ/mol of CO<SUB>2</SUB> for the potassium salt of <SMALL>l</SMALL>-alanine < 81.77 kJ/mol of CO<SUB>2</SUB> for MEA).</P>