Proof of concept: Integrated membrane distillation-forward osmosis approaches water production in a low-temperature CO2 capture

This study investigated the removal of CO from flue gas by an integrated membrane distillation-forward osmosis (MD–FO) system. Monoethanolamine (MEA) and sodium glycinate solutions were loaded with CO from a mixture of CO and N (1:9 in volume ratio) to simulate synthetic flue gas. CO desorption from the amine solution was evaluated using MD at 80 °C. Interaction between amines and the membrane polymeric matrix could alter the membrane surface hydrophobicity; however, under all experimental conditions it was still sufficiently hydrophobic for MD operation. Amine loss during MD operation for CO desorption was insignificant. FO was used to provide make-up water and cooling to the regenerated amine solution after CO desorption by MD. The results showed stable FO water flux when wastewater effluent was used as the source for make-up water. Repetitive CO loading and desorption experiments showed 87.0% and 88.1% CO re-absorption efficiency for MEA and sodium glycinate in the second cycle, respectively. Further investigation of this hybrid system is suggested to advance the CO desorption by MD process and water production by FO process. 2 2 2 2 2 2 2 2 2 2