title: Extraction of silver(I) from aqueous solutions in the absence and presence of copper(II) with a methimazole-based ionic liquid.
abstract: The ionic liquid (IL) 2-butylthiolonium bis(trifluoromethanesulfonyl)amide, [mimSBu][NTf(2)], facilitates the efficient extraction of silver(I) from aqueous media via interaction with both the cation and anion components of the IL. Studies with a conventional aqueous-IL two phase system as well as microextraction of silver(I) by a thick IL film adhered to an electrode monitored in situ by cyclic voltammetry, established that [mimSBu][NTf(2)] can extract electroactive silver(I) ions from an aqueous solution. The pH of the aqueous phase decreases upon addition of [mimSBu](+), which is attributed to partial release of the hydrogen attached to the N(3) nitrogen atom of the imidazolium ring. The presence of silver(I) further increase the acidity of the aqueous phase as a consequence of coordination with the IL cation component. Voltammetric and (1)H and (13)C NMR techniques have been used to establish the nature of the silver(I) complexes extracted, and show that the form of interaction with the IL differs from that outlined previously for the extraction of copper(II). Insights on the competition established when silver(I) is extracted in the presence of copper(II) are provided. Finally, it is noted that metallic silver can be directly electrodeposited at the electrode surface after extraction of silver(I) into [mimSBu][NTf(2)] and that back extraction of silver(I) into aqueous media is achieved by addition of an acidic aqueous solution.
authors: School of Chemistry and ARC Special Research Centre for Green Chemistry, Monash University, Clayton, Victoria 3800, Australia.
authors: Juan M
authors: JM
authors: Reyna-González
authors: Angel A J
authors: AA
authors: Torriero
authors: Amal I
authors: AI
authors: Siriwardana
authors: Iko M
authors: IM
authors: Burgar
authors: Alan M
authors: AM
authors: Bond
mesh_terms: D003300:Copper / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D004595:Electroplating; D006863:Hydrogen-Ion Concentration; D052578:Ionic Liquids / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008713:Methimazole / Q000737:chemistry*; D012834:Silver / Q000737:chemistry* / Q000302:isolation & purification; D014867:Water / Q000737:chemistry
chemical_list: D052578:Ionic Liquids; D014867:Water; D012834:Silver; D008713:Methimazole; D003300:Copper