A natural deep eutectic solvent-based aqueous biphasic system coupled with MoS₂ photocatalytic reduction for green recovery of gold from thiosulfate solution

Abstract

Aqueous two-phase system (ATPS) extraction combined with a natural deep eutectic solvent (NADES) is an environmentally friendly separation process. In this work, ATPSs were constructed for the first time using...

Outstanding Performance of the Deep Eutectic Solvent-Based Aqueous Biphasic System Constructed with Sodium Citrate for a Green Gold Separation

“…Meanwhile, the −CN group in Au­(CN) 2 – forms a new and stronger hydrogen bond (−CN···H–O) with the marginal −OH group of PEG 400. This forms a more stable extracted complex that is loaded in the DES-rich phase, replacing the original weaker hydrogen bonds (Br – ···H–O−) between Br – of the original P 4 Br and the marginal −OH of PEG 400.…”

“…Therefore, use of such DESs cannot replace the classic solvent extraction method of using an "extractant + diluent" combination, which goes against the original intention of using DESs as a green extractant. 18 To advance beyond the traditional extraction mode and to effectively address the above shortcomings, we intend to combine the advantages of DESs and the aqueous biphasic system (ABS) extraction. 19 Compared to the traditional extraction mode, an ABS is composed of two immiscible aqueous phases, both of which have high water content (70− 90%); this can preserve molecular stability and provide mild and environmentally friendly conditions.…”

“…In general, hydrophobic DESs have a high viscosity and need to be dissolved in fat or an aromatic diluent to reduce the mass transfer resistance during the extraction process. Therefore, use of such DESs cannot replace the classic solvent extraction method of using an “extractant + diluent” combination, which goes against the original intention of using DESs as a green extractant …”

Acid-Resistant Polyimide Ultrafiltration Membranes for Direct Separation of Lignin from Deep Eutectic Solvents

“…Deep eutectic solvents (DESs) have recently gained considerable interest due to their excellent ability to dissolve lignin from biomass. 6,7 DESs are liquid, low eutectic mixtures of hydrogen-bond acceptors and donors, 8,9 with many advantages including easy preparation, high purity, low toxicity, excellent biodegradability, low vapor pressure, high thermal stability, low volatility, nonflammability, and exceptional air stability. 10,11 Compared with conventional ionic liquids, their facile synthesis routes and the use of relatively economical components make them a popular choice for lignin extraction.…”

“…Conventional pretreatments, such as dilute acid and steam explosion, are not suitable for lignin extraction because they produce condensed lignin and/or pseudolignin. , Efforts for lignin valorization have driven the development of pretreatment methods using different solvents, such as ionic liquids and biomass-derived organic solvents. Deep eutectic solvents (DESs) have recently gained considerable interest due to their excellent ability to dissolve lignin from biomass. , DESs are liquid, low eutectic mixtures of hydrogen-bond acceptors and donors, , with many advantages including easy preparation, high purity, low toxicity, excellent biodegradability, low vapor pressure, high thermal stability, low volatility, nonflammability, and exceptional air stability. , Compared with conventional ionic liquids, their facile synthesis routes and the use of relatively economical components make them a popular choice for lignin extraction. , It is worth mentioning that acidic DESs have an excellent ability to extract lignin from lignocellulose. For example, choline chloride (ChCl):lactic acid (LA) can extract up to 93.1% of lignin from woody biomass and forages .…”