Efficiency Method for Methylene Blue Recovery Using Aqueous Two-Phase Systems based on Cholinium-Ionic Liquids

Abstract

Aqueous two phase-systems (ATPS) have been introduced as a new approach to remove dyes from aqueous discharges. Thus, this work evaluated the phase formation capacity in ATPS based on different organic solvents (1,3 dioxolane and 2-propanol) and cholinium-based salts (cholinium bitartrate - [Ch][Bit] and cholinium dihydrogencitrate - [Ch][DHCit]). The capacity in two-phase system form for both used solvents was higher with [Ch][Bit]. The ability to recover actual methylene blue dye was then evaluated for the type of phase-forming composition and equilibrium temperature. For solvents evaluated for their ability to form two phases, those formed with showed greater ability to induce ATPS. The best extraction efficiency (≈ 92 %) was achieved using the ATPS composed of 48 wt% of 1,3 dioxolane + 10.5 wt% of [Ch][Bit] + water at 15 ºC. Thus, it has been shown that ATPS based on organic solvents and cholinium-based ionic liquids have potential for application in dye extraction processes of the textile industry.