Molecular Insights into SO₂ Absorption by [EMIM][Cl]-Based Deep Eutectic Solvents

Abstract

Deep eutectic solvents (DESs) as promising green solvents have been proposed for the removal of SO 2 from fuel gases. In this work, an efficient SO 2 absorption strategy based on three 1-ethyl-3-methylimidazolium chlorine ([EMIM][Cl])-based DESs, that is, [EMIM][Cl]−ethylene glycol, [EMIM][Cl]− triethylene glycol, and [EMIM][Cl]−acetamide DESs, was investigated. A comparison of the predicted absorption efficiency via molecular dynamics (MD) and that obtained from experimental results is used to validate the simulated results.Then, the interaction energy and radial and spatial distribution functions are calculated based on the MD simulation results to provide molecular insights into the separation mechanism. The hydrogen bonding and van der Waals interactions between molecules and SO 2 were investigated by quantum chemical calculations. The results demonstrate that the anion ([Cl] − ) plays a significant role in the absorption process. As a further step, a modeling method for SO 2 absorption and DES recovery based on Aspen Plus is established. Under optimal operating conditions, the SO 2 absorption ratio exceeds 99.6%, and the DES recovery ratio is 99.9%. DESs, as a new type of absorbent, will provide new insights for the sustainable development of the green chemical industry.

Homologue-paired liquids as special non-ionic deep eutectic solvents for efficient absorption of SO2

“…10 In comparison with ILs, DESs can be synthesized from commercial reagents through easier processes, so that DESs are reckoned as more promising candidates for efficient acidic gas absorption. 11 So far, various DESs have been examined for SO 2 capture, such as choline-based DESs, 12 betaine-based DESs, 13 imidazolium-based DESs, 14 and azole-based DESs. 11 a ,15 However, due to the disadvantages such as high viscosity and corruption caused by halogen anions, DESs are still lacking practical applications.…”

Superefficient Absorption of Low-Concentration SO2 in Flue Gas Using New Ternary Imidazole-Based Deep Eutectic Solvents: Mechanism, Thermodynamics, and Process Analysis

“…The wet flue gas desulfurization (WFGD) and DES regeneration process were modeled and simulated by Aspen Plus V12 (Figure S3 of the Supporting Information), and the appropriate amount of absorbent was obtained through parameter adjustment. The absorption tower (absorber) used the Columns/RadFrac/ABSBR1 module, and the separation tower (DES regeneration) used the Splitter/V-DRUM1 module. , After the parameters were set, the experiment selects the UNIQUAC method. The flue gas temperature and pressure were set to 80 °C and 1.0 bar, respectively.…”

“…The absorption tower (absorber) used the Columns/RadFrac/ABSBR1 module, and the separation tower (DES regeneration) used the Splitter/V-DRUM1 module. 25,26 After the parameters were set, the experiment selects the UNIQUAC method. The flue gas temperature and pressure were set to 80 °C and 1.0 bar, respectively.…”

“…To predict the operating conditions and reduce the design time of the device, Aspen Plus V12 was used to simulate the single-tower absorption operation. 25 In a single tower to simulate the absorption process of SO 2 in flue gas, the influence of the SO 2 concentration and absorbent consumption on the SO 2 efficiency of the DES is plotted in Figure 11. As shown in Figure 11, the concentration of SO 2 from flue gas has almost no effect.…”

Rational Screening of Deep Eutectic Solvents for the Direct Extraction of α-Tocopherol from Deodorized Distillates

“…Moving beyond organic solvents and ILs, deep eutectic solvents (DESs) have newly emerged as another promising option for different chemical processes, − including the extraction of vitamin E . Bearing not only similar physicochemical properties to ILs, DESs also feature green and sustainable characters such as biodegradability, nontoxicity, and affordable cost. − A typical type of DES is generally formed by mixing an organic salt as the hydrogen bond acceptor (HBA) and a conventional nonsalt molecule as the hydrogen bond donor (HBD).…”