Development of back-extraction and recyclability routes for ionic-liquid-based aqueous two-phase systems
authors Claudio, AFM; Marques, CFC; Boal-Palheiros, I; Freire, MG; Coutinho, JAP
nationality International
journal GREEN CHEMISTRY
keywords BIPHASIC SYSTEMS; PHENOLIC-COMPOUNDS; WATER; SALTS; SOLVENTS; CATION; ANION; TOXICITY; PRODUCTS; RECOVERY
abstract In the last decade, aqueous two-phase systems (ATPS) composed of ionic liquids (ILs) and inorganic salts have been largely explored as novel extractive platforms. The use of ILs as phase-forming components in ATPS has led to outstanding extraction performances compared to more traditional approaches. Nevertheless, despite those exceptional achievements, IL regeneration, recycling and reuse lagged behind and still remain a challenging task towards the development of greener cost-effective processes. Aiming at overcoming these shortcomings, the phase diagrams of novel ATPS composed of imidazolium-based ILs and Na2CO3 or Na2SO4 were determined and their extraction efficiencies for a model antioxidant - gallic acid - were evaluated. The most promising IL-based ATPS were then used in sequential two-step cycles (product extraction/IL recovery) so as to evaluate the efficacy on the IL recyclability and reusability. Extraction efficiency values ranging between 73% and 99% were obtained in four sequential partitioning experiments involving gallic acid while allowing the regeneration of 94-95% of the IL and further reutilization. Moreover, to support the vast applicability of the back-extraction routes and the recyclability concept proposed here, the most prominent systems were further tested with two additional antioxidants, namely syringic and vanillic acids. In both examples, the extraction efficiencies were higher than 97%. The remarkable results obtained in this work support the establishment of IL-based ATPS as a sound basis of greener cost-effective strategies with a substantial reduction in the environmental footprint and economical issues.
publisher ROYAL SOC CHEMISTRY
issn 1463-9262
year published 2014
volume 16
issue 1
beginning page 259
ending page 268
digital object identifier (doi) 10.1039/c3gc41999a
web of science category Chemistry, Multidisciplinary; GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY
subject category Chemistry; Science & Technology - Other Topics
unique article identifier WOS:000328885600034

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