CO₂‐Philic Separation Membrane: Deep Eutectic Solvent Filled Graphene Oxide Nanoslits

Abstract

CO2 capture and sequestration is an energy‐intensive industry to deal with the global greenhouse effect. Membrane separation is considered a cost‐effective method to mitigate the emission of CO2. Though good separation performance and stability have been reported, supported ionic liquid membranes are still not widely applied for CO2 separation due to the high cost. As a novel analogous solvent to ionic liquid, deep eutectic solvent retains the excellent merits of ionic liquid and is cheap with facile preparation. Herein, a highly CO2‐philic separation membrane is constructed by nanoconfining choline chloride/ethylene glycol (ChCl/EG) deep eutectic solvent into graphene oxide nanoslits. Molecular dynamic simulation results indicate that the confinement makes a difference to the structure of the nanoconfined ChCl/EG liquid from their bulk, which remarkably facilitates CO2 transport. By tuning the molar ratio of ChCl/EG and thickness of the membrane, the resultant membrane exhibits outstanding separation performance for CO2 with excellent selectivity over other light gases, good long‐term durability, and thermal stability. This makes it a promising membrane for selective CO2 separation.

Recent Advances and Challenges of Deep Eutectic Solvent based Supported Liquid Membranes

“…Vacuum filtration coupled with impregnation was used for the fabrication of graphene oxide-ChCl-ethylene glycol DESbased composite SLMs (42). Lin (42) optimized the fabrication duration between 10 s and 2 h over the graphene oxide-ChClethylene glycol DES-based composite SLM.…”

“…Vacuum filtration coupled with impregnation was used for the fabrication of graphene oxide-ChCl-ethylene glycol DESbased composite SLMs (42). Lin (42) optimized the fabrication duration between 10 s and 2 h over the graphene oxide-ChClethylene glycol DES-based composite SLM. Although, this method produced SLMs with uniform morphology, its high capital cost and maintenance problems with frequent leakage limit its employment.…”

“…Despite the significant advantages of DES-based SLMs, their fabrication is a delicate process that depends on a number of parameters such as type of DES, its composition (20,29), the thickness of the membrane support (35)(36)(37), wettability (38), as well as additives (39)(40)(41). In addition, different fabrication methods such as immersion (20), pressure-based impregnation (29) and vacuum filtration (42) are influencing factors that affect membrane performances. Besides, process parameters also affect the permeation performance of DES-based SLMs in gases and liquid separation.…”

Facilitated Transport Membranes With Ionic Liquids for CO2 Separations

“…Among various nanomaterials, graphene oxide (GO) nanosheets received great attention due to their high flexibility, good mechanical strength, and easy processability. Lin et al ( 2019 ) confined a deep eutectic solvent that is selective to CO 2 , similar to ILs, into GO nanoslits as a highly CO 2 -philic GO-SILM. The group reported a structural change in the liquid that better promotes CO 2 transport, even though the liquid is not reactive with CO 2 .…”

Synthesis, Characterization, and CO2/N2 Separation Performance of POEM-g-PAcAm Comb Copolymer Membranes

“…Furthermore, it is possible to fabricate various membranes for different applications owing to the diverse monomers available and the polymers that are synthesized from them with different structural properties. In recent years, membrane technology for CO 2 separation has attracted significant research interest [ 9 , 10 , 11 , 12 ]. In particular, studies have reported on CO 2 /N 2 , CO 2 /CH 4 , and CO 2 /H 2 separation techniques [ 13 , 14 , 15 , 16 , 17 ].…”