It has been of long concern that the separation and recovery
of
NH3 from industrial processes, in addition to attracting
huge economic interest, also reduce environmental pollution. So, it
is very urgent to develop novel absorbents for highly efficient capture
of NH3. In this study, several novel tetrazole (TetrZ)-based
binary deep eutectic solvents (DESs) were formed by mixing TetrZ with
1,2,3-triazole (1,2,3-Tri), ethylene glycol (EG), 2-morpholinoethanol
(2-Mor), or N-methyldiethanolemine (MDEA) to absorb
NH3. TetrZ + 1,2,3-Tri (1:4, mole ratio) not only exhibits
higher NH3 absorption ability of 0.239 gNH3
·gDES
–1 than that of most
absorbents reported to date at 313.15 K and 101.3 kPa, but also shows
elevated selectivities of 592.7 for NH3/CO2,
654.5 for NH3/N2, and 1033.7 for NH3/O2. Meanwhile, TetrZ + 1,2,3-Tri (1:4) can be reused
10 times with good absorption capacity retained. Additionally, the
solubility data of NH3 were correlated by the reaction
equilibrium thermodynamic model. The NMR and FTIR spectroscopic characterizations
were also used to study the absorption mechanism, and quantum chemistry
calculation was utilized to further investigate the interactions between
NH3 and DESs from an atomic level perspective. The DESs
developed in the present work have the potential to capture NH3 sustainably, owing to their high solubility, superior selectivity,
and desirable reversibility.