Deep eutectic solvent-based blended membranes for ultra-super selective separation of SO₂

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Sulfur dioxide (SO2) is a major atmospheric pollutant contributing to acid rain and smog.
• Deep eutectic solvents (DESs) are emerging as green solvents for gas capture applications.
• Research on DES-based membranes for SO2 separation remains limited.

Purpose of the Study:

• To develop and evaluate novel polymer/DES blended membranes for selective SO2 separation.
• To investigate the performance of these membranes in separating SO2 from N2 and CO2.
• To explore the potential of these membranes for industrial applications like flue gas desulfurization.

Main Methods:

• Fabrication of polymer/DES blended membranes using poly(vinylidene fluoride) (PVDF) and a [Bmim]Br/diethylene glycol (DEG) DES.
• Gas permeation experiments to measure SO2, N2, and CO2 permeability and selectivity.
• Spectroscopic analysis to understand the interaction between SO2 and the DES.
• Long-term stability tests of the membranes under mixed gas conditions.

Main Results:

• The PVDF/DES blended membrane achieved a high SO2 permeability of 17480 Barrer.
• Ultrahigh SO2/N2 selectivity (3690) and SO2/CO2 selectivity (211) were obtained.
• Spectroscopic analysis revealed a highly-reversible multi-site interaction between SO2 and the DES.
• The membrane demonstrated stable performance in separating a mixed SO2/CO2/N2 gas stream for over 100 hours.

Conclusions:

• [Bmim]Br-based DESs are highly effective media for SO2 membrane separation.
• Polymer/DES blended membranes offer a promising, cost-effective solution for SO2 separation.
• These membranes show significant potential for applications in flue gas desulfurization.