Novel Biphasic Solvent with Tunable Phase Separation for CO2 Capture: Role of Water Content in Mechanism, Kinetics, and Energy Penalty

Jiexu Ye, Chenkai Jiang, Han Chen, Yao Shen, Shihan Zhang, Lidong Wang, Jianmeng Chen

Research output: Contribution to journalArticlepeer-review


The biphasic solvent-based absorption process has been regarded as a promising alternative to the monoethanolamine (MEA)-based process because of its high absorption capacity, phase separation behavior, and potential for conserving energy for CO2 capture. A trade-off between the absorption capacity and phase separation ratio is critical for developing an advanced biphasic solvent. Typically, water content in the biphasic solvent can be manipulated to tune the phase separation behavior. To explore the relationship between water content and phase separation behavior, an inert organic solvent, 1-methyl-2-pyrrolidinone, was added as a substitute for water in a biphasic solvent, specifically a triethylenetetramine (TETA) and 2-(diethylamino)ethanol (DEEA) blend. Moreover, the water content-kinetics and thermodynamics relationships were also evaluated. Experimental results revealed that reducing the water content was beneficial for phase separation but adverse for adsorption capacity. Kinetic analysis indicated that the water content did not significantly affect the rate of CO2 absorption at a rich loading. Furthermore, the regeneration heat decreased with the water content. The regeneration heat of TETA-DEEA with a water content of 20 wt % was almost 50% less than that of MEA solution. 13C nuclear magnetic resonance analysis revealed that the water content did not affect the reaction mechanism between CO2 and amines.

Original languageEnglish (US)
Pages (from-to)4470-4479
Number of pages10
JournalEnvironmental Science and Technology
Issue number8
StatePublished - Apr 16 2019
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry


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