Facilitated Transport of CO₂ through Gel-coated Liquid Membranes Using 2,3-diaminopropionic Acid as Carrier

Abstract

Experiments on the facilitated transport of CO 2 were performed using gel-coated liquid membranes containing aqueous solutions of a novel carrier, 2, 3-diaminopropionic acid DAPA , and the transport properties and stability of the membranes were studied. A feed gas consisting of 10% CO 2 and 90% N 2 was used as a model flue gas from power plants. It was found that gel-coated membranes showed higher CO 2 and N 2 permeances than that of conventional supported liquid membranes prepared by impregnating microporous membranes with the same carrier solution. The CO 2 permeance Q CO2 observed with the gel-coated membrane at 25 was 1.68 10 -4 cm 3 STP / cm 2 s cm Hg and the selectivity of CO 2 over N 2 was 100.It was confirmed by a long-term experiment performed at the permeate side pressure of 40mmHg that the gel-coated membrane was stable with no decrease in Q CO2 for one-month continuous testing period, which might be due to the hydroscopic nature of the gel layer. In the experiment using a plate-and-frame type membrane module with a membrane area of 1400cm 2 , CO 2 was enriched from 10 % to 80 %.