Tuning Functionalized Ionic Liquids for CO2 Capture

Abstract

The increasing concentration of CO2 in the atmosphere is related to global climate change. Carbon capture, utilization, and storage (CCUS) is an important technology to reduce CO2 emissions and to deal with global climate change. The development of new materials and technologies for efficient CO2 capture has received increasing attention among global researchers. Ionic liquids (ILs), especially functionalized ILs, with such unique properties as almost no vapor pressure, thermal- and chemical-stability, non-flammability, and tunable properties, have been used in CCUS with great interest. This paper focuses on the development of functionalized ILs for CO2 capture in the past decade (2012~2022). Functionalized ILs, or task-specific ILs, are ILs with active sites on cations or/and anions. The main contents include three parts: cation-functionalized ILs, anion-functionalized ILs, and cation-anion dual-functionalized ILs for CO2 capture. In addition, classification, structures, and synthesis of functionalized ILs are also summarized. Finally, future directions, concerns, and prospects for functionalized ILs in CCUS are discussed. This review is beneficial for researchers to obtain an overall understanding of CO2-philic ILs. This work will open a door to develop novel IL-based solvents and materials for the capture and separation of other gases, such as SO2, H2S, NOx, NH3, and so on.

Conversion of carbon dioxide into solid carbon materials – a mini review

“…Task-specific ionic liquids have active sites on cations or/ and anions, which can be used for carbon dioxide capture and substantial activation. 66 The catalytic conversion of carbon dioxide can be achieved at ambient pressure and requires no additional energy input. 67 CO 2 can be absorbed in ionic liquids physically or chemically.…”

Tuning Ionic Liquid-Based Catalysts for CO2 Conversion into Quinazoline-2,4(1H,3H)-diones

“…CO 2 -philic task-specific ILs or functional ILs used in CO 2 capture have been developed during two decades [ 29 , 30 , 31 , 32 ]. The Functional ILs mainly based on functional anions include single-site anions, such as amino anions, [ 33 , 34 ] carboxylate anions, [ 35 ] alcoholate anion, [ 36 ] phenolate anions, [ 37 , 38 ] and azolate anions, [ 39 , 40 , 41 ] and multiple-site anions, such as pyridinolate anions, [ 42 , 43 ] imide anions, [ 44 , 45 , 46 , 47 ] and hydantoin anions [ 48 , 49 ].…”

Novel amino acid ionic liquids prepared via one‐step lactam hydrolysis for the highly efficient capture of CO2

“…Since then, a series of amino-functionalized ILs have been proposed and designed for CO 2 capture. 9,[23][24][25][26][27][28] Amino acid ionic liquids (AAILs) are a subclass of special representative ILs that are functionalized with amino and carboxylic groups originating from amino acids. 22,29 AAILs are featured with additional advantages such as biodegradability and biological activity.…”

“…A covalently tethered primary amine group on the imidazolium cation enables the chemical absorption of 0.5 mol of CO 2 per mole of the IL at ambient condition. Since then, a series of amino‐functionalized ILs have been proposed and designed for CO 2 capture 9,23–28 …”