Utilization of Deep Eutectic Solvents to Reduce the Release of Hazardous Gases to the Atmosphere: A Critical Review

Abstract

The release of certain gases to the atmosphere is controlled in many countries owing to their negative impact on the environment and human health. These gases include carbon dioxide (CO2), sulfur oxides (SOx), nitrogen oxides (NOx), hydrogen sulfide (H2S) and ammonia (NH3). Considering the major contribution of greenhouse gases to global warming and climate change, mitigation of these gases is one of the world’s primary challenges. Nevertheless, the commercial processes used to capture these gases suffer from several drawbacks, including the use of volatile solvents, generation of hazardous byproducts, and high-energy demand. Research in green chemistry has resulted in the synthesis of potentially green solvents that are non-toxic, efficient, and environmentally friendly. Deep eutectic solvents (DESs) are novel solvents that upon wise choice of their constituents can be green and tunable with high biocompatibility, high degradability, and low cost. Consequently, the capture of toxic gases by DESs is promising and environmentally friendly and has attracted much attention during the last decade. Here, we review recent results on capture of these gases using different types of DESs. The effect of different parameters, such as chemical structure, molar ratio, temperature, and pressure, on capture efficiency is discussed.

New Solvents for CO2 and H2S Removal from Gaseous Streams

“…Similar works considering H 2 S are less diffuse. Shah et al (2017) [32] screened ionic liquids for H 2 S absorption, while Wazeer et al 2021 [33] reviewed recent results on capture of hazardous gases (NH 3 , SO x , NO x and H 2 S) using different types of deep eutectic solvents.…”

“…When an IL is one of the components in DESs, the advantages of DESs over ILs disappear [171]. Wazeer et al (2021) [33] reviewed recent results on capture of acid gases using different types of DESs and confirmed the lack of research on H 2 S capture through DES.…”

“…It is therefore too early to understand their real potential for large-scale applications. As recommended by Wazeer et al (2021) [33], pilot plant campaigns should be performed in order to move toward an industrial scale utilization of the selected DESs in the capture of CO 2 under different operating conditions.…”

Carbon Dioxide Solubility in Nonionic Deep Eutectic Solvents Containing Phenolic Alcohols

“…CO 2 capture is one application that can benefit from DES. Existing studies have demonstrated the potential of DES for CO 2 capture ( Krishnan et al, 2020 ; Song et al, 2020 ; Wazeer et al, 2021a ; Wazeer et al, 2021b ). However, most studies investigating CO 2 capture in DES proposed using ionic DES, which has the same drawbacks as those related to IL, especially in terms of hygroscopicity.…”

Deep eutectic solvents composed of bio-phenol-derived superbase ionic liquids and ethylene glycol for CO2 capture

“…[11][12][13][14][15][16][17] The applications of DESs as carbon capture materials have also been extensively investigated in recent years, 18,19 and DESs that can chemically capture CO 2 attract great interest from researchers due to their high CO 2 capacities. [20][21][22][23][24] Zhang et al studied the CO 2 capture by DESs composed of MEA and an ionic liquid (IL) 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), in which CO 2 was captured through the reaction between CO 2 and the amino group of MEA. 25 Trivedi et al found that DESs formed by HBDs ethylenediamine (EDA) and monoethanolammonium chloride ([MEAH][Cl]) exhibited high CO 2 capacities due to the reaction between CO 2 and EDA.…”