CO₂ Absorption in Mixed Aqueous Solution of MDEA and Cholinium Glycinate

Abstract

A new mixed solvent system that consists of cholinium glycinate ([Cho][Gly]) and aqueous Nmethyldiethanolamine (MDEA) solution was developed in this work to serve as CO 2 absorbent. The equilibrium absorption was carried out to investigate the effect of solution composition, pressure, and temperature on CO 2 absorption performance. The effect of CO 2 absorption on the viscosity of the aqueous solutions was studied, and the regeneration efficiency of the aqueous solutions was also investigated. The results showed that the CO 2 absorption loading decreased with increasing [Cho][Gly] concentration and temperature, and the absorption loading strongly depended on CO 2 partial pressure. The reactivity of MDEA was significantly enhanced with the addition of [Cho][Gly]. The aqueous solution with (10 wt % [Cho][Gly] + 20 wt % MDEA) showed an optimal CO 2 absorption and high regeneration efficiency. Furthermore, the CO 2 absorption mechanism in the aqueous [Cho][Gly]-MDEA solution was explored by 13 C nuclear magnetic resonance, which indicated that the CO 2 absorption in the aqueous [Cho][Gly]-MDEA solution was a zwitterion mechanism.

State-of-the-Art Organic- and Inorganic-Based Hollow Fiber Membranes in Liquid and Gas Applications: Looking Back and Beyond

“…These limitations lead to the progress of alternative absorbents like amino acid salt solutions [ 603 ], nanofluids [ 604 , 605 ], and ionic liquids [ 588 , 599 , 600 , 601 ], which exhibit ameliorated absorption capacity, stability, and regeneration efficiency. Apart from that, recent engineering approaches to structural steric effect [ 606 ] and blending [ 594 , 607 ] of amine absorbents have been reported. Other applications of membrane contactors include oxygenation/deoxygenation [ 608 , 609 ], ozonation [ 610 , 611 , 612 ], gas dehumidification [ 613 , 614 , 615 , 616 , 617 ], and olefin/paraffin separation [ 618 , 619 ].…”

CO2 removal from anaesthesia circuits using gas-ionic liquid membrane contactors

“…The combination of the cholinium cation with biocompatible anions from renewable sources, such as amino acids, results in low toxic, biocompatible, and cost-effective ILs with recognised efficiency for CO 2 capture [90,[143][144][145][146].…”

Site-Specific Interactions in CO2 Capture by Lysinate Anion and Role of Water Using Density Functional Theory

“…In traditional amines, the most proposed mechanism of reaction of CO 2 in the presence of water is considered to follow carbamate → bicarbonate → carbonate path. 26,34,36,37 This pathway considers amine to be the primary nucleophile for an attack on CO 2 . However, AA anions like [Lys] − can take an alternative path of direct bicarbonate formation in which the first and ratedetermining step is protonation of amine leaving the formation of hydroxide such as…”

“…However, the understanding of reaction mechanisms involving CO 2 capture and the role of water as a base in [Lys] − –CO 2 interactions have remained largely unexplored. In traditional amines, the most proposed mechanism of reaction of CO 2 in the presence of water is considered to follow carbamate → bicarbonate → carbonate path. ,,, This pathway considers amine to be the primary nucleophile for an attack on CO 2 . However, AA anions like [Lys] − can take an alternative path of direct bicarbonate formation in which the first and rate-determining step is protonation of amine leaving the formation of hydroxide such as which subsequently results in a barrierless reaction between OH – and CO 2 , producing bicarbonate.…”

“…However, AA anions like [Lys] − can take an alternative path of direct bicarbonate formation in which the first and rate-determining step is protonation of amine leaving the formation of hydroxide such as which subsequently results in a barrierless reaction between OH – and CO 2 , producing bicarbonate. Yuan et al in their experimental work discussed this to be one of the pathways for the reaction of CO 2 in an aqueous mixture of cholinium glycinate and methyldiethanolamine. In case of neutral amines, this mechanism is less favorable, but it requires a systematic examination for AA anions where the path 1 is expected to be observed.…”