Applicability of a Supported Liquid Membrane in the Enrichment and Determination of Cadmium from Complex Aqueous Samples

Abstract

A supported liquid membrane is developed for the separation of Cd from either high in salinity or acidity aqueous media. The membrane consisted of a durapore (polyvinylidene difluoride) polymeric support impregnated with a 0.5 M Aliquat 336 solution in decaline. The effect of carrier concentration, organic solvent and feed and receiving solutions on the metal permeability is studied. This system allows the effective transport of trace levels of Cd through the formation of CdCl42−, which is the predominant species responsible for the extraction process, in both NaCl and HCl solutions. The supported liquid membrane system in a hollow fibre configuration allows the enrichment and separation of trace levels of Cd from spiked seawater samples, facilitating the analytical determination of this toxic metal.

An Efficient Polymer Inclusion Membrane-Based Device for Cd Monitoring in Seawater

“…The transport process can be described by the reaction between the metal and the carrier (R 4 P + Cl − ) present in the PIM: n R 4 P + Cl − PIM + [CdCl n +2 ] n− (aq) → [(PR 4 ) n CdCl n +2 ] PIM + n Cl − (aq) where n can be one or two, and the subscripts aq and PIM denote the aqueous and membrane phases, respectively. It is worth mentioning that when Aliquat 336 is used as the extractant, it has been reported that CdCl 4 2− species are responsible for the extraction in non-viscous media [ 3 ], whereas CdCl 3 − species are responsible for the extraction when viscous diluents are used [ 18 ].…”

“…The impregnated fiber was effective to preconcentrate Cd from seawater samples into a 1.5 M HNO 3 solution (used as a stripping phase). More recently, a supported liquid membrane (SLM) containing this IL was developed and studied in both flat-sheet and hollow fiber configurations to separate Cd from complex aqueous samples [ 3 ]. It was found that using a 2 M HCl solution containing Cd, Cu, Ni, and Pb as a feed phase, only Cd was transported.…”

Characterisation of rare earth elements and toxic heavy metals in coal and coal fly ash

“…Due to its low operating costs, minimal handling procedures, low energy requirement and low solvent consumption, the liquid membrane extraction (LME) process has been proposed as a more efficient and cost effective alternative to solvent extraction processes for the recovering REEs from coal y ash. [56][57][58] As the y ash materials need no pulverisation, and only a readily available acid (ethanoic acid) is required to extract the REEs, this process is potentially highly cost-effective. Compared to REE recovery via total acid digestion of y ash materials, the proposed process greatly reduces the toxicity of waste to be handled, which translates to lower cost.…”

Determination of Glyphosate and AMPA in Food Samples Using Membrane Extraction Technique for Analytes Preconcentration

“…In SLM, a hydrophobic porous polymeric membrane holds the membrane liquid (membrane phase) into its micro-pores by capillary action. It has been proved that high viscosity (up to 500 cP) may slow down the displacement of the liquids from the micron pores under pressure and improve the SLM stability [25]. Aliquat 336 is used as a complex with counter ions (chlorides) to allow it to be dissolved in the hydrophobic organic phase (di-n-hexyl ether (DHE), a membrane diluent).…”