New aqueous two-phase system formed by piperazinium-based surface-active ionic liquid for extraction of dyes
Aqueous two-phase systems (ATPSs) as alternatives to traditional liquid–liquid extraction systems have been used intensively in recent years. In this work, a new ATPS composed of a piperazinium-based surface-active ionic liquid (SAIL), 1-(2-hydroxyethyl)piperazinium laurate ([HEP][C 11 CO 2 ]), and a commercial cationic surfactant, dodecyldimethylbenzylammonium chloride (DDBAC) was prepared. The phase diagram for the ternary system DDBAC + [HEP][C 11 CO 2 ] + H 2 O was determined, and the effects of composition and temperature on phase behaviors and properties were investigated. Phase separation was found spontaneous and thermodynamically favored when the mass fraction of water ( w 3 ) exceeded 0.60, primarily due to the salting-out of the hydrophilic ions [HEP] + and Cl − in the bottom phase. Micelles were observed in the top phase where high concentrations of the hydrophobic ions [DDBA] + and [C 11 CO 2 ] − were present. Increasing the water content at a fixed surfactant-to-SAIL molar ratio resulted in a decreased top phase volume, while the extraction efficiency ( EE ) and the distribution coefficient ( D ) were both increased for extractions of Basic Blue 7 and Allura Red AC. When w 3 reached 0.96 and the initial concentration of dye was below 1 × 10 −4 mol·L −1 , the EE values exceeded 98 % with all the D values surpassing 100, indicating the promising potential for SAIL-ATPS applications.
危险品化学品经营许可证（带存储）