Study on Carbon Dioxide Capture Using Ternary Betaine-Based Deep Eutectic Solvents

Area of Science:

• Chemical Engineering
• Materials Science
• Environmental Science

Background:

• Existing ternary betaine (Be)-based deep eutectic solvents (DESs) exhibit limitations in regenerability and water absorption.
• Developing efficient CO2 capture materials is crucial for environmental sustainability.

Purpose of the Study:

• To synthesize and characterize novel ternary Be-based DESs incorporating diethanolamine (DEA) as a promoter.
• To investigate the impact of DEA, temperature, and flow rate on CO2 absorption capacity.
• To evaluate the regenerability and water interaction of the developed DESs for CO2 capture.

Main Methods:

• Preparation of three ternary Be-based DESs with varying molar ratios of Be, ethylene glycol (EG), and DEA.
• Experimental investigation of CO2 absorption under different conditions (temperature, flow rate).
• Assessment of CO2 absorption capacity, effect of water addition, and regenerability over multiple cycles.

Main Results:

• The optimal molar ratio of 1:5:8 (Be:EG:DEA) achieved a CO2 absorption capacity of 0.207 g CO2/g DES at 30 °C and 50 mL/min.
• Water addition to the DES system led to dissolution and inhibited CO2 absorption.
• The ternary DESs maintained a CO2 absorption capacity above 0.176 g CO2/g DES after five absorption-desorption cycles, indicating good regenerability.

Conclusions:

• The addition of diethanolamine significantly enhances the CO2 absorption performance of betaine-based deep eutectic solvents.
• The developed ternary DESs show promising potential for CO2 capture applications due to their capacity and recyclability.
• Further research is needed to understand the role of water and optimize the system for industrial applications.