Dual-Functionalized Ionic Liquid Biphasic Solvent for Carbon Dioxide Capture: High-Efficiency and Energy Saving

Area of Science:

• Chemical Engineering
• Environmental Science
• Materials Science

Background:

• Traditional CO2 capture solvents like monoethanolamine (MEA) suffer from high viscosity and energy-intensive regeneration.
• Developing novel solvents with improved performance and lower energy demands is crucial for effective carbon capture.

Purpose of the Study:

• To develop a novel biphasic solvent for CO2 capture that overcomes the limitations of high viscosity and difficult regeneration.
• To investigate the CO2 loading capacity, viscosity, and regeneration efficiency of a dual-functionalized ionic liquid ([DETAH][Tz]) in a 1-propanol-water system.

Main Methods:

• A dual-functionalized ionic liquid ([DETAH][Tz]) was dissolved in a 1-propanol-water mixture to create a biphasic solvent.
• The CO2 loading, phase behavior, viscosity, and regeneration performance of the novel solvent were evaluated.
• Regeneration heat duty was compared to [DETAH][Tz]-water and MEA systems.

Main Results:

• The biphasic solvent achieved high CO2 loading (1.713 mol mol-1) with reduced viscosity (2.57 mPa s).
• The solvent demonstrated excellent regeneration efficiency, maintaining 90% of initial loading after five cycles, promoted by 1-propanol.
• The CO2 absorption products were enriched in the lower water phase, while 1-propanol concentrated in the upper phase.
• The heat duty was significantly lower (29.93% less than [DETAH][Tz]-water and 47.63% less than MEA).

Conclusions:

• The [DETAH][Tz]-1-propanol-water system presents a promising, energy-efficient alternative for CO2 capture.
• The biphasic nature and the role of 1-propanol contribute to enhanced CO2 loading and regeneration.
• This novel solvent addresses key challenges in current CO2 capture technologies.