In Situ Formation of Ionic Liquid by Metathesis Reaction for the Rapid Removal of Bisphenol A from Aqueous Solutions

Abstract

In this work we present a rapid and easy method to remove the totality of bisphenol A from aqueous solutions using ionic liquid (IL). Dispersive liquid–liquid microextraction is employed. The IL 1-octyl-3-methylimidazolium bis((trifluoromethane)sulfonyl)imide ([C8C1im] [NTf2]) is formed in situ because of the mixture of 1-octyl-3-methylimidazolium chloride ([C8C1im]Cl) and lithium bis(trifluoromethanesulfonyl)imide (Li[NTf2]) aqueous solutions. A cloud of microdroplets of IL formed by the dispersion generated through the precursors metathesis reaction allows the rapid and total extraction of bisphenol A (BPA). After centrifugation, the formed IL phase is deposited at the bottom of the flask and the total amount of BPA is extracted in the sedimented phase. The volume of IL is very low, in the order of microliters, which enables us to remove all the BPA from the solution. The technique studied is highly efficient, cost-effective, and presents less environmental impact than other extraction techniques, thus becoming an outstanding alternative to the most commonly used methods. BPA concentration is determined by high performance liquid chromatography by injecting the IL phase directly. An extraction kinetic model for the kinetic profile has been tested for this method, which allows to infer the ideal experimental conditions to execute the extraction method.

Evaluation of an Ion-Associate Phase Formed In Situ from the Aqueous Phase by Adding Benzethonium Chloride and Sodium Ethylbenzenesulfonate for Microextraction

“…The in situ formation of micro-liquid phases from the aqueous phase can be achieved by the use of ionic liquids [15][16][17][18][19], deep eutectic solvents [2,[20][21][22][23] and their combination with dispersive liquid-liquid extraction [19,23]. However, to the best of our knowledge, no study has yet elucidated the optimum concentration of the reagents used to form the solvent.…”