Efficient and reversible absorption of NH3 by functional azole–glycerol deep eutectic solvents

New Journal of Chemistry Pub Date: 2019-06-21 DOI: 10.1039/C9NJ01788G

Abstract

The hydrogen bond donor (HBD) glycerol (Gly) and hydrogen bond acceptors (HBA) selected among 1,2,4-triazole (Tri), imidazole (Im), tetrazole (Tz), 1-methyl-triazole (Tri-Me), 3-mercapto-1,2,4-triazole (Tri-SH), 3-amino-1,2,4-triazole (Tri-NH2), 3-cyano-1,2,4-triazole (Tri-CN), and 4-formalimidazole (Im-CHO) were paired to construct functional deep eutectic solvents (DESs) that were then utilized as ammonia (NH3) absorbents. The influences of the HBA in DESs, temperature, and partial pressure of NH3 on the NH3 absorption performance were systematically investigated. The results illustrated that all the DESs exhibited efficient and reversible absorption for NH3, and Tri–Gly possessed higher absorption capacity than Im–Gly, with the maximum absorption capacity of 0.115 gram NH3 per gram DES of Tri–Gly (1?:?3) at 313.15 K and 1.0 bar. The NH3-saturated DES could be easily recycled five times with a persistent absorption performance. The absorption mechanism was further deduced by the NMR and FTIR spectroscopy. These DESs acted as potential absorbents for NH3 due to their good absorption performance and reversibility.

Graphical abstract: Efficient and reversible absorption of NH3 by functional azole–glycerol deep eutectic solvents
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