Application of Phosphonium Ionic Liquids as Ion Carriers in Polymer Inclusion Membranes (PIMs) for Separation of Cadmium(II) and Copper(II) from Aqueous Solutions

Abstract

Facilitated transport through polymer inclusion membranes (PIMs) is a promising method for simultaneous separation and removal of valuable and toxic metal ions from aqueous solutions. Recently, ionic liquids (ILs) have been used as extracting agents for metal ions due to their unique physicochemical properties. This paper presents research on the facilitated transport of cadmium(II) and copper(II) ions from aqueous chloride solutions through PIMs with phosphonium ILs as new selective ion carriers. Cellulose triacetate membranes containing o-nitrophenyl octyl ether (ONPOE) as a plasticizer and Cyphos IL 101 [trihexyl(tetradecyl)phosphonium chloride] or Cyphos IL 104 [trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate] as the ion carriers have been prepared and applied for investigations. Cd(II) ions were transported preferably from hydrochloric acid solutions containing Cu(II) ions through the PIMs. Higher selectivity coefficient of Cd(II) over Cu(II) (SCd/Cu) from 0.1 mol·dm−3 hydrochloric acid was obtained for PIM with Cyphos IL 104 as the ion carrier. The influence of HCl and NaCl concentrations in the source phase on metal ion transport across PIM doped with Cyphos 104 was studied. It was found that the initial fluxes of Cd(II) and Cu(II) increase with increasing chloride ions concentration in the source phase. The selectivity coefficient for Cd(II) over Cu(II) decreases with increasing HCl concentration in the source phase. The results suggest that the separation system presented in this paper can be useful for the removal of Cd(II) from acidic chloride solutions in the presence of Cu(II).

Supported Ionic Liquid Membranes for Metal Separation

“…The eiciency strongly depended on the type of carrier and the receiving phase. Separation of Cd(II) and Cu(II) from hydrochloric acid solution was conducted using PIMs composed of Cyphos IL 101 and 104, and CTA [60]. High selectivity of Cd(II) over Cu(II) was obtained because of diference in the stability constants of Cd(II) and Cu(II) of Eq.…”

Characterization of polymer inclusion membranes (PIM) containing phosphonium ionic liquids and their application for separation of Zn(II) from Fe(III)

“…Some authors proposed ionic liquids (ILs), e.g. methyltrioctylammonium or trihexyl(tetradecyl)phosphonium salts, as metal ion carriers in PIMs . The interest in application of ILs for separation processes has been increasing recently because ILs exhibit many unique properties such as high thermal stability, non‐flammability and extractability for different organic and inorganic compounds.…”

“…Until now PIMs containing various ion carriers have been proposed for separation of a variety of metal ions, i.e. noble metals, actinides, lanthanides, and heavy metals, such as zinc, iron, cadmium, copper, nickel, lead, chromium, mercury, cobalt, and manganese . Also, PIMs were applied for the transport of such organic compounds as oxalic, tartaric, lactic or citric acid …”

“…The back‐extraction was successfully achieved with 1 mol L ‐1 H 2 SO 4 . Cyphos IL 101 or Cyphos IL 104 were used also for facilitated transport of Cd(II) and Cu(II) across PIMs …”

Electrochemical Characterization of a Polymer Inclusion Membrane Made of Cellulose Triacetate and Aliquat 336 and Its Application to Sulfonamides Separation

“…However, the use of ILs as carriers favors the flexibility and mechanical strength of PIMs avoiding the need of the addition of other components, and their high viscosity helps to retain them in the polymer gel-like network. Different commercial ILs such as Cyphos 101 (trihexyl(tetradecyl)phosphonium chloride), Cyphos 102 (trihexyl(tetradecyl)phosphonium bromide), Cyphos 104 (trihexyl(tetradecyl)phosphonium bis-2,4,4-(trimethylpentyl) phosphinate), or Aliquat 336 (trioctylmethyl ammonium chloride) have been reported as carriers in PIMs used in the separation of metal species such as Cd, Cu, or In, organic compounds such as antibiotics or water pollutants [13][14][15][16][17].…”