２，３‐ジアミノプロピオン酸をキャリアとする含浸液膜によるＣＯ２の促進輸送

Abstract

A novel carrier, 2, 3-diaminopropionic acid (DAPA), was proposed for the facilitated transport of CO2, and experiments on the separation of CO2 from a mixture of 10% CO2 and 90% N2 were performed using supported liquid membranes to evaluate the performance of this carrier. DAPA exists in four kinds of ionic forms in the aqueous solution depending on its pH. It was found that the membranes containing DAPA (C), which has one free amino group and the membrane containing DAPA (D), which has two free amino groups, showed much higher CO2 permeance Qco2 and selectivity of CO2 from N2 than the membranes containing monoethanolamine or Cs2CO3 as CO2 carriers. It was deduced from the observed solubility of CO2 in aqueous DAPA solutions that one mole of CO2 reacts with two moles of DAPA (C) and also that CO2 reacts with one mole of DAPA (D). Both Qco2 and selectivity increased with increasing temperature. The values of Qco2 and selectivity observed with the DAPA (C) membrane at 25°C were 1.00×10-4cm3 (STP) / (cm2s cmHg) and 650, respectively, and the corresponding values at 70°C were 1.79×10-4cm3 (STP) / (cm2s cmHg) and 1240, respectively. The membrane was table at high temperatures probably because the loss of DAPA from the membrane by its evaporation was very small due to its very low vapor pressure. These results suggest that DAPA is promising as a carrier for CO2.