scholarly journals Capture of Acidic Gases from Flue Gas by Deep Eutectic Solvents

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1268
Author(s):  
Yan Wang ◽  
Shuhang Ren ◽  
Yucui Hou ◽  
Weize Wu

Up to now, many kinds of deep eutectic solvents (DESs) were investigated for the capture of acidic gases from flue gases. In this review, non-functionalized and functionalized DESs, including binary and ternary DESs, for SO2, CO2 and NO capture, are summarized based on the mechanism of absorption, physical interaction or chemical reaction. New strategies for improving the absorption capacity are introduced in this review. For example, a third component can be introduced to form a ternary DES to suppress the increase in viscosity and improve the CO2 absorption capacity. DESs, synthesized with halogen salt hydrogen bond acceptors (HBAs) and functionalized hydrogen bond donors (HBDs), can be used for the absorption of SO2 and NO with high absorption capacities and low viscosities after absorption, due to physicochemical interaction between gases and DESs. Emphasis is given to introducing the absorption capacities of acidic gases in these DESs, the mechanism of the absorption, and the ways to enhance the absorption capacity.

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5595
Author(s):  
Mohaned Aboshatta ◽  
Vitor Magueijo

Amine absorption (or amine scrubbing) is currently the most established method for CO2 capture; however, it has environmental shortcomings and is energy-intensive. Deep eutectic solvents (DESs) are an interesting alternative to conventional amines. Due to their biodegradability, lower toxicity and lower prices, DESs are considered to be “more benign” absorbents for CO2 capture than ionic liquids. In this work, the CO2 absorption capacity of choline-chloride/levulinic-acid-based (ChCl:LvAc) DESs was measured at different temperatures, pressures and stirring speeds using a vapour–liquid equilibrium rig. DES regeneration was performed using a heat treatment method. The DES compositions studied had ChCl:LvAc molar ratios of 1:2 and 1:3 and water contents of 0, 2.5 and 5 mol%. The experimental results showed that the CO2 absorption capacity of the ChCl:LvAc DESs is strongly affected by the operating pressure and stirring speed, moderately affected by the temperature and minimally affected by the hydrogen bond acceptor (HBA):hydrogen bond donator (HBD) molar ratio as well as water content. Thermodynamic properties for CO2 absorption were calculated from the experimental data. The regeneration of the DESs was performed at different temperatures, with the optimal regeneration temperature estimated to be 80 °C. The DESs exhibited good recyclability and moderate CO2/N2 selectivity.


2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Rima J. Isaifan ◽  
Abdukarem Amhamed

In the recent past few years, deep eutectic solvents (DESs) were developed sharing similar characteristics to ionic liquids but with more advantageous features related to preparation cost, environmental impact, and efficiency for gas separation processes. Amongst many combinations of DES solvents that have been prepared, reline (choline chloride as the hydrogen bond acceptor mixed with urea as the hydrogen bond donor) was the first DES synthesized and is still the one with the lowest melting point. Choline chloride/urea DES has proven to be a promising solvent as an efficient medium for carbon dioxide capture when compared with amine alone or ionic liquids under the same conditions. This review sheds light on the preparation method, physical and chemical characteristics, and the CO2 absorption capacity of choline chloride/urea DES under different temperatures and pressures reported up to date.


2021 ◽  
Vol 22 (17) ◽  
pp. 9551
Author(s):  
Patrycja Makoś-Chełstowska ◽  
Edyta Słupek ◽  
Aleksandra Kramarz ◽  
Jacek Gębicki

During biogas combustion, siloxanes form deposits of SiO2 on engine components, thus shortening the lifespan of the installation. Therefore, the development of new methods for the purification of biogas is receiving increasing attention. One of the most effective methods is physical absorption with the use of appropriate solvents. According to the principles of green engineering, solvents should be biodegradable, non-toxic, and have a high absorption capacity. Deep eutectic solvents (DES) possess such characteristics. In the literature, due to the very large number of DES combinations, conductor-like screening models for real solvents (COSMO-RS), based on the comparison of siloxane activity coefficient of 90 DESs of various types, were studied. DESs, which have the highest affinity to siloxanes, were synthesized. The most important physicochemical properties of DESs were carefully studied. In order to explain of the mechanism of DES formation, and the interaction between DES and siloxanes, the theoretical studies based on σ-profiles, and experimental studies including the 1H NMR, 13C NMR, and FT-IR spectra, were applied. The obtained results indicated that the new DESs, which were composed of carvone and carboxylic acids, were characterized by the highest affinity to siloxanes. It was shown that the hydrogen bonds between the active ketone group (=O) and the carboxyl group (-COOH) determined the formation of stable DESs with a melting point much lower than those of the individual components. On the other hand, non-bonded interactions mainly determined the effective capture of siloxanes with DES.


Author(s):  
Edyta Słupek ◽  
Patrycja Makoś

The paper presents a synthesis of deep eutectic solvents (DESs) based on choline chloride (ChCl) as hydrogen bond acceptor and phenol (Ph), glycol ethylene (EG), and levulinic acid (Lev) as hydrogen bond donors in 1:2 molar ratio. DESs were successfully used as absorption solvents for removal of dimethyl disulfide from (DMDS) from model biogas steam. Several parameters affecting the absorption capacity and absorption rate has been optimized including kind of DES, temperature, the volume of absorbent, model biogas flow rate, and initial concentration of DMDS. Furthermore, reusability and regeneration of DESs by means of adsorption and nitrogen barbotage followed by the mechanism of absorptive desulfurization by means of density functional theory (DFT) as well as FT-IR analysis were investigated. Experimental results indicate that the most promising DES for biogas purification is ChCl:Ph, due to high absorption capacity, relatively long absorption rate, and easy regeneration. The research on the absorption mechanism revealed that van der Waal interaction is the main driving force for DMDS removal from model biogas.


Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1034 ◽  
Author(s):  
Guoqing Wu ◽  
Ying Liu ◽  
Guangliang Liu ◽  
Xiaoying Pang

Because of the appealing properties, ionic liquids (ILs) are believed to be promising alternatives for the CO2 absorption in the flue gas. Several ILs, such as [NH2emim][BF4], [C4mim][OAc], and [NH2emim[OAc], have been used to capture CO2 of the simulated flue gas in this work. The structural changes of the ILs before and after absorption were also investigated by quantum chemical methods, FTIR, and NMR technologies. However, the experimental results and theoretical calculation showed that the flue gas component SO2 would significantly weaken the CO2 absorption performance of the ILs. SO2 was more likely to react with the active sites of the ILs than CO2. To improve the absorption capacity, the ionic liquid (IL) mixture [C4mim][OAc]/ [NH2emim][BF4] were employed for the CO2 absorption of the flue gas. It is found that the CO2 absorption capacity would be increased by about 25%, even in the presence of SO2. The calculation results suggested that CO2 could not compete with SO2 for reacting with the IL during the absorption process. Nevertheless, SO2 might be first captured by the [NH2emim][BF4] of the IL mixture, and then the [C4mim][OAc] ionic liquid could absorb more CO2 without the interference of SO2.


2019 ◽  
Vol 55 (10) ◽  
pp. 1426-1429 ◽  
Author(s):  
Ge Cui ◽  
Meng Lv ◽  
Dezhong Yang

Azolide-based deep eutectic solvents exhibit a high CO2 absorption capacity by forming carbonate species.


Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7167
Author(s):  
Ze Wang ◽  
Zonghua Wang ◽  
Jie Chen ◽  
Congyi Wu ◽  
Dezhong Yang

Recently, deep eutectic solvents (DESs), a new type of solvent, have been studied widely for CO2 capture. In this work, the anion-functionalized deep eutectic solvents composed of phenol-based ionic liquids (ILs) and hydrogen bond donors (HBDs) ethylene glycol (EG) or 4-methylimidazole (4CH3-Im) were synthesized for CO2 capture. The phenol-based ILs used in this study were prepared from bio-derived phenols carvacrol (Car) and thymol (Thy). The CO2 absorption capacities of the DESs were determined. The absorption mechanisms by the DESs were also studied using nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and mass spectroscopy. Interestingly, the results indicated that CO2 reacted with both the phenolic anions and EG, generating the phenol-based carbonates and the EG-based carbonates, when CO2 interacted with the DESs formed by the ILs and EG. However, CO2 only reacted with the phenolic anions when the DESs formed by the ILs and 4CH3-Im. The results indicated that the HBDs impacted greatly on the CO2 absorption mechanism, suggesting the mechanism can be tuned by changing the HBDs, and the different reaction pathways may be due to the steric hinderance differences of the functional groups of the HBDs.


2020 ◽  
Vol 12 (4) ◽  
pp. 1619 ◽  
Author(s):  
Edyta Słupek ◽  
Patrycja Makoś

The paper presents a synthesis of deep eutectic solvents (DESs) based on choline chloride (ChCl) as hydrogen bond acceptor and phenol (Ph), glycol ethylene (EG), and levulinic acid (Lev) as hydrogen bond donors in 1:2 molar ratio. DESs were successfully used as absorption solvents for removal of dimethyl disulfide (DMDS) from model biogas steam. Several parameters affecting the absorption capacity and absorption rate have been optimized including kinds of DES, temperature, the volume of absorbent, model biogas flow rate, and initial concentration of DMDS. Furthermore, reusability and regeneration of DESs by means of adsorption and nitrogen barbotage followed by the mechanism of absorptive desulfurization by means of density functional theory (DFT) as well as FT-IR analysis were investigated. Experimental results indicate that the most promising DES for biogas purification is ChCl:Ph, due to high absorption capacity, relatively long absorption rate, and easy regeneration. The research on the absorption mechanism revealed that van der Waal interaction is the main driving force for DMDS removal from model biogas.


2019 ◽  
Vol 116 ◽  
pp. 00078 ◽  
Author(s):  
Edyta Słupek ◽  
Patrycja Makoś ◽  
Jacek Gębicki ◽  
Andrzej Rogala

Biogas from landfills and wastewater treatment facilities typically contain a wide range of volatile organic compounds (VOCs), that can cause severe operational problems when biogas is used as fuel. Among the contaminants commonly occur aromatic compounds, i.e. benzene, ethylbenzene, toluene and xylenes (BTEX). In order to remove BTEX from biogas, different processes can be used. A promising process for VOCs removal is their absorption in deep eutectic solvents (DES). In this work, three DES: ([ChCl] U TEG [choline chloride]:urea:tetraethylene glycol (1:2:2), [ChCl] U [choline chloride]:urea (1:2), [ChCl] DEG [choline chloride]:diethylene glycol (1:2)) and water were tested to toluene absorption in concentration of 2000 ppm v/v in nitrogen stream. The results demonstrated the high absorption capacity of toluene using DES based on glycols.


2020 ◽  
Author(s):  
Matteo Tiecco ◽  
Irene Di Guida ◽  
Pier Luigi Gentili ◽  
Raimondo Germani ◽  
Carmela Bonaccorso ◽  
...  

<div><div><div><p>The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs.</p><p>In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes.</p></div></div></div>


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