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

Abstract

BACKGROUND Hydrometallurgical separation of Zn(II) from Fe(III) from HCl solutions is an important issue to regenerate spent effluents. Polymer inclusion membranes (PIMs) are an attractive technique for selective separation and concentration of low concentrated target metal ions, as an alternative to liquid–liquid extraction. RESULTS PIMs containing phosphonium ionic liquids trihexyl(tetradecyl)phosphonium chloride (Cyphos IL101) or bis(2,4,4‐trimethylpentyl)phosphinate (Cyphos IL104), as metal ion carriers, o‐nitrophenyloctyl ether (NPOE) as a plasticizer and triacetate cellulose (CTA) as a polymer matrix were prepared and characterized by contact angle measurements, scanning electron microscopy, atomic force microscopy and nanoindentation measurements. An important aspect was to determine the influence of PIMs ageing on their morphology and efficiency of Zn(II) transport. Finally, PIMs were applied for separation of Zn(II) from Fe(III). CONCLUSION The surface of the IL‐containing PIMs was characterized as hydrophilic, rough, without apparent pores. However, phase contrast images indicated that the plasticized membranes were not fully homogeneous. Stability of the PIMs, particularly of those without the plasticizer or without the carrier, is affected by ageing. Finally, a membrane‐based successful separation of Zn(II) from Fe(III) was developed with 1 mol L‐1 HCl as a stripping phase for Fe(III), while the majority of Zn(II) were retained in the feed phase (SFe(III)/Zn(II) = 8.85). © 2017 Society of Chemical Industry

Recent Advances in the Selective Transport and Recovery of Metal Ions using Polymer Inclusion Membranes

“…Essentially, the transport performance of PIMs necessitates a comprehensive consideration of their composition, uniformity, and internal and surface morphology. [ 49 ]…”

“…In addition, quaternary phosphonium ionic liquids belong to another common neutral carrier group, including Cyphos IL 101, Cyphos IL 104, and Cyphos IL 167. These ionic liquids typically contain salts with cation and anion exchange properties, [ 49 ] which give them similar characteristics to the basic carrier Aliquat 336 despite their vastly different applications. [ 47 ] Quaternary phosphonium ionic liquids have recently been widely utilized by numerous researchers for the separation of various metal ions, as demonstrated in Table 3.…”

“…Essentially, the transport performance of PIMs necessitates a comprehensive consideration of their composition, uniformity, and internal and surface morphology. [49] Some commonly utilized plasticizers are depicted in Figure 2, where these plasticizers include 2-NPPE, 2-NPOE, T2EHP, and DOP. Among these plasticizers, 2-NPPE and 2-NPOE remain the most commonly used plasticizers.…”

“…Neutral or solvating carriers Base polymers Plasticizers Target metal species TOPO CTA+TTA -Li (I) [22] TBP CTA 2-NPOE La (III) [85] TPDGA/THDGA/TDDGA CTA 2-NPOE Am (III), Pu (IV), U (II), and Th (IV) [86] Cyphos IL 104/Cyphos IL 101/Cyphos IL 167 CTA/PVC 2-NPOE Zn (II) [49] Cyphos IL 104 CTA 2-NPOE Cd (II), [87] Zn (II) [ 49,88] PVDF-HFP 2-NPOE Au (III) [89] PVDF-HFP -Lu (III) and Yb (III) [90] Cyphos IL 101 CTA 2-NPPE Cd (II), Co (II), and Ni (II) [91] CTA 2-NPOE Cu (II) and Cd (II), [92] Zn (II), [ 49,88] Cr (VI) [60] PVC 2-NPOE Cr (VI) [60] PVDF-HFP 2-NPOE V (V) [ 47,93] Cr (VI) [60] P 88812 Cl PVDF-HFP 2-NPOE Pd (II), [94] Pt (IV), and Pd (II) [95] 1-octanol PVC -Cr (VI) [37] highly selective separation and recovery of Li (I) from K (I) and Na (I) (Figure 4). [ 24,50,99,100] Pb (II), Zn (II), Cd (II), Ni (II), Cu (II), and Co (II) [ 101] Calix [4]resorcinarenes CTA 2-NPOE Zn (II) [ 102] Diglycolamide-functionalized calix [4]arene CTA 2-NPOE Am (III), Pu (IV), U (II), and Th (IV) [98] Dicyclohexano 18 crown 6 PVC TOPO Rb (I) [ 103] Alkyl (aliphatic) resorcinarene derivative CTA 2-NPPE Pb (II), Cd (II), and Zn (II) [ 104] 1-alkyl-2-methylimidazole CTA 2-NPPE Cu (II), Co (II), Ni (II), and Zn (II) [97] Alkylimidazoles CTA 2-NPPE Cu (II), Zn (II), Co (II), and Ni (II) [ 105] Cyanex 923 and LIX-54-100 as carriers was fabricated by Paredes et al [15] for the selective transport of Li (I) from natural seawater.…”

Selective Separation of Acetic and Hexanoic Acids across Polymer Inclusion Membrane with Ionic Liquids as Carrier

“…It should be pointed out that the majority of carriers in PIMs have plasticizing properties and there is no need to add additional plasticizer to the membrane composition [22,23,24]. The popularity of PIMs is mainly due to their excellent stability than that of other kinds of LMs such as bulk liquids (BLMs), emulsion liquids (ELMs), and supported liquid membranes (SLMs) [25]. Furthermore, PIMs can provide many other advantages in studies such as high selectivity, simple preparation, long term use, excellent stability and versatility, quick transport, and flexible design [23,26,27], and thus possess much potential.…”