Highly efficient and reversible low-concentration SO2 absorption in flue gas using novel phosphonium-based deep eutectic solvents with different substituents

Zhao, Yu Hong; Dou, Jinxiao; Wei, Aoran; Khoshkrish, Salman; Yu, Jianglong

doi:10.1016/j.molliq.2021.117228

Cited by 19 publications

(15 citation statements)

References 48 publications

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“…This indicates the formation of hydrogen bonds between EG and SO 2 /NO x gas, which may promote SO 2 and NO 2 absorption. 30 The detected peaks all showed a slight change in the height and strength, which is believed to be due to the reaction of SO 2 and NO 2 with OH···Br – .…”

Section: Resultsmentioning

confidence: 93%

Effective Absorption Mechanism of SO₂ and NO₂ in the Flue Gas by Ammonium-Bromide-Based Deep Eutectic Solvents

et al. 2022

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Simultaneous capture of SO 2 and NO x from flue gas is critical for coal-fired power generation. In this study, environmentally friendly and high-performance deep eutectic solvents based on ethylene glycol and ammonium bromide were designed to capture SO 2 and NO 2 simultaneously. The SO 2 and NO 2 absorption performances and absorption mechanisms were systematically investigated by 1 H NMR and Fourier transform infrared (FT-IR) spectroscopy in combination with ab initio calculations using Gaussian software. The results showed that EG-TBAB DESs can absorb low concentrations of SO 2 and NO 2 from the flue gas simultaneously at low temperatures (≤50 °C). 1 H NMR, FT-IR, and simulation results indicate that SO 2 and NO 2 are absorbed by forming EG-TBAB-SO 2 –NO 2 complexes, Br – is the main active site for NO 2 absorption, and NO 2 is more active in an EG-TBAB-NO 2 –SO 2 complex than SO 2 . EG-TBAB DESs exhibit outstanding regeneration capability, and absorption capacities remain unchanged after five absorption–desorption cycles. The fundamental understanding of simultaneous capture of SO 2 and NO 2 from this study enables DES structures to be rationally designed for efficient and low-cost desulfurization and denitrification reagents.

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Section: Resultsmentioning

confidence: 93%

Effective Absorption Mechanism of SO₂ and NO₂ in the Flue Gas by Ammonium-Bromide-Based Deep Eutectic Solvents

et al. 2022

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“…In Figure a, the FTIR peak of unreacted EG–Im–MTPB (1:2:1) DES disappeared at 1530 and 1257 cm –1 , which is caused by the protonation reaction between N–H of Im and SO 2 . Immediately after, the FTIR spectra of DES after SO 2 absorption exhibited four new vibration peaks at 1636, 1588, 1042, and 955 cm –1 . , The peaks that appeared at 955 and 1042 cm –1 were S–O stretch vibrations, and the peaks at 1588 and 1636 cm –1 were credited to the cooperation between the electronegative N particle of Im and the S particle of SO 2 . , In addition, the peak at 615 cm –1 shifted to 629 cm –1 after SO 2 absorption, suggesting that there is a strong chemical interaction of charge between Br – and SO 2 Figure b exhibits the change in 1 H NMR spectra of unreacted and reacted EG–Im–MTPB (1:2:1) DES.…”

Section: Resultsmentioning

confidence: 98%

“…Thus, increasing the SO 2 absorption capacity of DESs can meet the market demand and reduce the cost of industrial raw materials. On the basis of the above reports and analysis, ,, we synthesized ternary imidazole-based DESs with imidazole (Im) and EG as the hydrogen bond donor (HBD) and MTPB as the hydrogen bond acceptor (HBA) (Figure S1 of the Supporting Information) because DESs can chemically absorb low-concentration SO 2 using the electronegative N atom from Im and the electronegative Br atom from MTPB. In comparison to the dual EG–MTPB DES, the ternary DES significantly increased the SO 2 absorption capacity.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

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New ternary deep eutectic solvents (DESs), including imidazole (Im), ethylene glycol (EG), and methyltriphenyl phosphonium bromide (MTPB), were synthesized at different molar ratios to absorb SO 2 in flue gas. Excitingly, the EG−Im−MTPB (1:2:1) DES has achieved the unexpected achievement of its absorption capacity being greatly improved to 0.65 g of SO 2 /g of DES (4.43 mol/mol) at 3000 ppm and 30 °C, which is the best performing DES for capturing SO 2 under the same conditions ever reported. The aftereffects of thermodynamic investigation demonstrate that there is a solid compound communication between EG−Im−MTPB (1:2:1) DES and SO 2 . In particular, the enthalpy change (Δ r H m ), entropy change (Δ r S m ), and Gibbs free energy change (Δ r G m ) were plainly determined as −50.45 kJ/mol, −114.57 J mol −1 K −1 , and −16.20 kJ/mol, separately. The Fourier transform infrared, 1 H nuclear magnetic resonance, and quantum chemistry calculation results confirm that multiple active sites, including the N atom of Im and the Br atom of MTPB, are the main factors by which DES effectively absorbs SO 2 . Further, a UNIQUAC method by Aspen Plus V12 is set up for the SO 2 absorption process with 6000 m 3 /h flue gas, indicating that the EG− Im−MTPB (1:2:1) DES can completely absorb SO 2 in the flue gas when the consumption of DES is 26.8 m 3 /h.

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“…Thermal expansion coefficient α is usually used to evaluate the variation tendency of ILs volume with temperature. It can be seen that [TMEA][MOAc] has the smallest α, indicating that it has the weakest thermal expansion capacity and therefore requires only a smaller container volume and lower investment during transportation and storage. The Arrhenius equation [eq ] is a common empirical equation that can accurately describe the relationship between temperature and viscosity (Figure b) where η is the viscosity, cP; E a represents the activation energy in kJ·mol –1 for viscosity; the value of universal gas constant R is 8.314 J·K –1 ·mol –1 ; and η 0 denotes the viscosity at infinite temperature, cP.…”

Section: Results and Discussionmentioning

confidence: 99%

Rich Ether-Based Protic Ionic Liquids with Low Viscosity for Selective Absorption of SO₂ through Multisite Interaction

Liu

Cai

Zhang

et al. 2022

Ind. Eng. Chem. Res.

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Four low-viscosity protic ionic liquids (PILs) with the tertiary amine and rich ether skeletons are designed for selective absorption of SO2. To evaluate the selective absorption of SO2 by these PILs, the solubilities of SO2, CO2, and H2S are measured in the temperature range of 303.2–333.2 K and pressures up to 120 kPa by a volumetric method, respectively. The absorption of SO2 by [TMEA][MOAc] at 303.2 K and 101.3 kPa was found to be 10.424 mol·kg–1 (4.310 mol·mol–1), and the ideal selectivity of SO2/CO2 was 86.83. In addition, the solubility data are fitted using a reaction equilibrium thermodynamic model to obtain thermodynamics parameters including Gibbs free energy change (Δr G m), enthalpy change (Δr H m, Δphy H m, Δchem H m), and entropy change (Δr S m). The mechanism of SO2 absorption by [TMEA][MOAc] is also investigated by FTIR and NMR analyses. Mechanistic and thermodynamic studies suggest that the high SO2 absorption is attributed to the O–SO2 multisite physical interaction. These ether-rich PILs are considered as a promising absorber because of their high SO2 solubility, good cycling performance, and low viscosity before and after absorption.

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Highly efficient and reversible low-concentration SO2 absorption in flue gas using novel phosphonium-based deep eutectic solvents with different substituents

Cited by 19 publications

References 48 publications

Effective Absorption Mechanism of SO₂ and NO₂ in the Flue Gas by Ammonium-Bromide-Based Deep Eutectic Solvents

Effective Absorption Mechanism of SO₂ and NO₂ in the Flue Gas by Ammonium-Bromide-Based Deep Eutectic Solvents

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

Rich Ether-Based Protic Ionic Liquids with Low Viscosity for Selective Absorption of SO₂ through Multisite Interaction

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Highly efficient and reversible low-concentration SO2 absorption in flue gas using novel phosphonium-based deep eutectic solvents with different substituents

Cited by 19 publications

References 48 publications

Effective Absorption Mechanism of SO2 and NO2 in the Flue Gas by Ammonium-Bromide-Based Deep Eutectic Solvents

Effective Absorption Mechanism of SO2 and NO2 in the Flue Gas by Ammonium-Bromide-Based Deep Eutectic Solvents

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

Rich Ether-Based Protic Ionic Liquids with Low Viscosity for Selective Absorption of SO2 through Multisite Interaction

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Product

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Effective Absorption Mechanism of SO₂ and NO₂ in the Flue Gas by Ammonium-Bromide-Based Deep Eutectic Solvents

Effective Absorption Mechanism of SO₂ and NO₂ in the Flue Gas by Ammonium-Bromide-Based Deep Eutectic Solvents

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

Rich Ether-Based Protic Ionic Liquids with Low Viscosity for Selective Absorption of SO₂ through Multisite Interaction