Design of eco-friendly aqueous two-phase systems extraction of industrial finishing dyes

Cholinium bitartrate (N1112OHC4H5O6) has been demonstrated to be a promising phase disengagement agent in aqueous solutions of biodegradable non-ionic surfactants belonging to Tween family. For the first time, these systems were demonstrated to be versatile tools to efficiently extract two of the most frequently used groups of dyes, like di-azo and anthraquinone dyes. To do that, the binodal curves of the aqueous two phase systems (Tween 20 or Tween 80 + N1112OHC4H5O6 + H2O) were characterized at different temperatures (between 293.2 K and 323.2 K) and ambient pressure (0.1 MPa). Besides, prior to apply these systems for dyes extraction, the tie-lines were characterized, and all the data were suitably described by empirical equations. Analysis from an environmental point of view of capacity of the proposed eco-friendly ionic liquid for the extraction of Add Black 48 and Reactive Black 5 dyes from aqueous solutions reveals environmental and efficiency advantages when compared with conventional imidazolium-based ionic liquids. (C) 2019 Published by Elsevier B.V.