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

Abstract

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.

Screening of Pure ILs and DESs for CO2 Separation, N2O Separation, and H2S Separation Processes

“…Te desorption temperatures of absorbents in this study are identical to those in our previous work [12], which are 299.15-323.15 K for physical absorbents, 299.15-345.15 K, and 299.15-353.15 K for chemical DES and ILs, respectively. Te absorption pressure is iterated until ∆G 3 � 0, and the optimal conditions, absorbent amount, and energy consumption are obtained.…”

“…Te optimal operating conditions are achieved when ∆G 3 is equal to 0, and the performance of diferent absorbents can be evaluated. Terefore, using the thermodynamic analysis as proposed in our previous work, the number of absorbents and the energy consumption are combined by Gibbs free energy change [12,13].…”

“…Ionic liquids exhibit remarkable properties for gas separation, such as high solubility for CO 2 , N 2 O, and H 2 S. Although ILs have been used in studies related to gas separation [7][8][9][10], the large-scale commercial usage of ILs is limited by their high toxicity, poor biodegradability, and high cost. Deep eutectic solvents have low toxicity, biodegradability, and low cost and are proposed as promising CO 2 absorbents [11][12][13][14].…”

Magnetic deep eutectic solvents: formation and properties

“…[19][20][21] Furthermore, they manifested a notable performance in gas separation based on the coordination ability of metal ions as well. 22,23 This type of DES typically includes a magnetic transition metal, such as Fe(III), Co(II), Ni(II), Mn(II) and Zn(II), called magnetic DESs (MDESs) here. The physicochemical properties of MDESs are important to help us to understand their features and have a better application in various fields.…”

Facile Synthesis of Alkaline Ternary Deep Eutectic Solvents: Application for Effective and Reversible SO2 Uptake

“…Recently, room-temperature ionic liquids (ILs) and deep eutectic solvents (DESs, as IL analogues) have received widespread attention in the field of gas absorption. − The excellent properties of ILs and DESs, like lower volatility, higher thermal stability, and designable structure, make them possible to be applied as favorable new-generation absorbents. − Here, ILs or DESs with alkaline N groups (like amides, amines, pyridines, , azoles, and imidazoles ,, ) or halogen anions (Cl – and Br – ) , could be designed for the effective capture of SO 2 . After absorption, these absorbents with saturated SO 2 could be regenerated under a lower pressure and higher temperature environment (such as 0.1 bar and 333.15 K).…”