Metal chlorides-promoted ammonia absorption of deep eutectic solvent

Ammonia is considered as a promising hydrogen or energy carrier. Ammonia absorption or adsorption is an important aspect for both ammonia removal, storage and separation applications. To these ends, a wide range of solid and liquid sorbents have been investigated. Among these, the deep eutectic solvent (DES) is emerging as a promising class of ammonia absorbers. Herein, we report a novel type of DES, i.e. , metal-containing DESs for ammonia absorption. Specifically, the NH 3 absorption capacity is enhanced by ca. 18.1–36.9% when a small amount of metal chlorides , such as MgCl 2 , MnCl 2 etc. , are added into a DES composed of resorcinol (Res) and ethylene glycol (EG). To our knowledge, the MgCl 2 /Res/EG (0.1:1:2) DES outperforms most of the reported DESs. The excellent NH 3 absorption performances of metal–containing DESs have been attributed to the synergy of Lewis acid–base and hydrogen bonding interactions. Additionally, good reversibility and high NH 3 /CO 2 selectivity are achieved over the MgCl 2 /Res/EG (0.1:1:2) DES, which enables it to be a potential NH 3 absorber for further investigations.