Absorption and desorption of CO"2 into five aqueous tertiary amine solvents and their blends with MAPA were studied using a screening apparatus. Results showed that MAPA significantly enhanced both CO"2 absorption rate and absorption capacity. The solvent system with the highest CO"2 absorption capacity and cyclic CO"2 capacity was 3M DEEA + 1M MAPA with a CO"2 loading of 2.72 mole CO"2/kg solution and a cyclic CO"2 capacity of 2.06 mole CO"2/kg solution. For both the single and the blended systems, the CO"2 absorption capacity decreased when increasing the number of ethanolamine groups on the tertiary amine (DEEA -> EDEA -> TEA) and when the alkyl chain length in the tertiary amine was increased (EDEA -> BDEA). When the alkyl amine group in the tertiary amine became hindered (BDEA -> t-BDEA), the CO"2 absorption capacity increased.
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