Highly efficient and selective separation of ammonia by deep eutectic solvents through cooperative acid-base and strong hydrogen-bond interaction

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Developing new and facile strategies for multiple-site reversible chemical absorption of pollutant gases is of wide interests in chemical engineering research. Herein, a series of lithium (Li)-triethylene glycol (TEG)-chelated ionic liquids (ILs) with crownether-like cation and different anions were designed. The Li-TEG-chelated ILs were prepared in quantitative yields by simply mixing equimolar TEG and Li salts. It is found that the chelation of TEG with Li + activates the hydroxyl sites in TEG for strong interaction with ammonia (NH 3 ). Thus, the hydroxyl sites chelated with Li + , as well as the chelation-unsaturated Li + , provide the multiple sites for chemical absorption of NH 3 in Li-TEG-chelated ILs. Moreover, the absorption of NH 3 in Li-TEGchelated ILs is totally reversible, with the NH 3 solubilities remaining unchanged after eight times of recycling. The results obtained herein can provide useful guidance for the construction of gas absorbents with high capacity and excellent reversibility.

Section: Resultssupporting

confidence: 77%

Section: Methodsmentioning

confidence: 99%

Section: Measurements Of Nh 3 Solubilitiesmentioning

confidence: 99%

“…This is a phenomenon commonly observed for the densities and viscosities of gas absorbents. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] The density of Li-…”

Section: Characterizations Of Li-teg-chelated Ilsmentioning

confidence: 99%

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Chelation‐activated multiple‐site reversible chemical absorption of ammonia in ionic liquids

Cai

Zhang

et al. 2022

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“…The densities and viscosities data of liquid absorbent are fundamental physical properties for the devise of gas absorption process. [22][23][24] As shown in Figure 1 1) and (2), 25,26 respectively.…”

Section: Physical Propertiesmentioning

confidence: 83%

Cuprous‐based composite ionic liquids for the selective absorption of CO: Experimental study and thermodynamic analysis

Tao

Gao

et al. 2022

Three cuprous-based composite ionic liquids (ILs) [EimH][OAc]-xCuOAc (x = 0.5, 0.6, 0.7) were prepared and employed for efficient absorption of CO. It is shown that the cuprous composite IL [EimH][OAc]-0.6CuOAc exhibited the largest absorption capacity for CO (0.031 g/g at 293.15 K and 1 bar) and had a record CO/N 2 selectivity of 967, which is better than most of common ILs and solvents reported in the literature. The results of Fourier transform infrared (FTIR) spectra, electrospray ionization mass spectrometry (ESI-MS) analysis, and theoretical calculations reveal that such superior CO capacity mainly resulted from two kinds of chemical interaction between CO and the active anionic species [Cu(OAc) 2 ] À in [EimH][OAc]-0.6CuOAc. Furthermore, a "deactivated IL model" was further proposed to accurately describe the absorption behavior of CO in [EimH][OAc]-0.6CuOAc, in which the thermodynamic parameters including Henry's law constants, reaction equilibrium constants, and absorption enthalpies were estimated by the correlation of the experimental solubilities of CO.

Remarkable NH₃ absorption in metal‐based deep eutectic solvents by multiple coordination and hydrogen‐bond interaction

Cheng

Lan

et al. 2022

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The elimination and recycling of NH3 from the vented circulating stream of NH3 synthesis process is of great significance to the protection of air environment and saving of NH3 product. Deep eutectic solvents (DESs) with as many weak acidic sites as possible are anticipated to exhibit high efficiency for NH3 absorption at low pressures. Herein, we designed and prepared a series of metal‐based DESs by mixing EaCl, metal chloride (SnCl2, ZnCl2, FeCl3, or CoCl2), and Gly. The physiochemical properties, NH3 absorption performance, and mechanism of prepared metal‐based DESs were investigated systematically. It is found that considerably high solubilities of NH3 in DESs can be achieved by utilizing the multiple coordination and hydrogen‐bond interaction with NH3 provided by metal ions and Gly respectively. The values of NH3 solubilities (17.55 mol/kg at 298.2 K and 103.0 kPa, and 10.24 mol/kg at 298.2 K and 6.8 kPa) are the highest reported to date.