abstract
The number of applications involving ionic liquids has dramatically increased in the past few years, and their production and use in a large scale will inevitably lead to their dispersion into water streams (either by wastewater disposal or accidental leakage). Studies on the removal and recovery of ionic liquids from wastewater streams are therefore of crucial importance, yet particularly scarce. In this work, the use of aluminium salts is proposed to concentrate and remove ionic liquids from aqueous solutions. Two aluminium-based salts (Al-2(SO4)(3) and AlK(SO4)(2)center dot 12H(2)O) were used to treat various aqueous solutions of ionic liquids containing imidazolium-, pyridinium-and phosphonium-based fluids. The gathered results show the enhanced ability of these salts to remove and recover ionic liquids from aqueous media. The minimum recovery efficiency achieved was 96%, whereas for a large array of systems recoveries of circa 100% of ionic liquid were attained. The residual concentrations of ionic liquids in water range from 0.01 to 6 wt%. The results reported disclose a novel promising technique for the recovery and treatment of aqueous effluents contaminated with ionic liquids by using salts commonly employed in water treatment processes, allowing thus its easy scale-up and adaptation to new processes involving ionic liquids.
keywords
FUNCTIONALIZED SIDE-CHAINS; DIFFERENT HEAD GROUPS; BIPHASIC SYSTEMS; 2-PHASE SYSTEMS; MUTUAL SOLUBILITIES; POLYETHYLENE-GLYCOL; PHASE COMPOSITIONS; WASTE-WATER; EXTRACTION; TOXICITY
subject category
Chemistry
authors
Neves, CMSS; Freire, MG; Coutinho, JAP
our authors
Catarina Maia Seco Seiça Neves
Assistant Researcher
Mara Guadalupe Freire Martins
Coordinating ResearcherGroups
G4 - Renewable Materials and Circular Economy
G5 - Biomimetic, Biological and Living Materials
Projects
acknowledgements
This work was financed by national funding from FCT Fundacao para a Ciencia e a Tecnologia, through the projects Pest-C/CTM/LA0011/2011 and PTDC/AAC-AMB/119172/2010. C. M. S. S. N. and M. G. F. also acknowledge FCT for the doctoral grant SFRH/BD/70641/2010 and the postdoctoral grant SFRH/BPD/41781/2007, respectively.