Selective thiacalix[4]arene bearing three amide groups as ionophore of binary Pd(II) and Au(III) extraction by a supported liquid membrane system

An Ionic Supported Liquid Membrane for the Recovery of Bisphenol A from Aqueous Solution

In this work, a flat supported liquid membrane (FSLM) was applied for the extraction of bisphenol A (BPA) from aqueous solutions, using an ionic liquid as a carrier. The liquid membrane consists of tricaprylmethylammonium chloride (aliquat 336^®) diluted in 2-octanol. Furthermore, to obtain the best transport efficiency, the impacts of various experimental parameters were investigated. These parameters included aliquat 336^® concentration, the concentration of BPA in the feed phase, the pH of the feed phase, the concentration of NaOH in the receiving phase, the polymeric support nature, the percentage of extractant in the organic phase, and the solvent nature. The optimum conditions of the experiment were 50% (v/v) aliquat 336^®/2-octanol as the organic phase, a transport time of 8 h, and 1 × 10^-2 mol L^-1 NaOH as the receiving phase. The BPA was successfully recovered (the recovery percentage was about 89%). Supported liquid membrane-based aliquat 336^®/2-octanol displayed an acceptable stability with re-impregnation after 5 days of operation.

Carrier-mediated extraction: Applications in extraction and microextraction methods

The present review is mainly focused on the overview of carrier mediated extraction (principles and applications) being reported over the last two decades and discusses the extraction process through carriers in various extraction methods such as Bulk liquid membranes, supported liquid membranes, emulsion liquid membranes and polymer inclusion membranes. Several types of carriers such as neutral, anionic, cationic, macrocyclic and supramulecular carriers are discussed. Also their application for metal, anions, drugs and environmental compounds are investigated. Carriers have been demonstrated to be useful for the selective extraction and recovery of numerous cations and anions enhancing the extraction properties of traditional solvent extraction and ion-exchange processes. Several types of carriers have different transport mechanisms. In these mechanisms, transport configurations are addressed and emphasized and the detailed information on the type of carrier are presented along with their specific separation modes. The performance of different carriers in terms of selectivity as well as efficiency are also discussed. Finally, the application of different carriers for the extraction of various compounds are compared and reviewed. To our best knowledge no reviews have been published on carrier-mediated extraction methods.

Effect of spacer length of ionic liquid-type imidazolium gemini surfactant-based water-in-oil microemulsion for the extraction of gold from hydrochloric acid

The effect of the spacer length of [C₁₄-n-C₁₄im]Br₂ surfactants on Au(iii) extraction performance was investigated for the first time.

Novel polyazamacrocyclic receptor decorated core–shell superparamagnetic microspheres for selective binding and magnetic enrichment of palladium: synthesis, adsorptive behavior and coordination mechanism

Novel core–shell superparamagnetic microspheres decorated with polyazamacrocyclic receptors for selective enrichment of palladium.

New short-channel SBA-15 mesoporous silicas functionalized with polyazamacrocyclic ligands for selective capturing of palladium ions in HNO3 media

Novel polyazamacrocyclic ligand decorated short-channel mesoporous silicas with the ability to selectively capture palladium ions in HNO₃ solutions.

Selone behavior towards palladium(ii) extraction with hydrophobic ionic liquids and mechanism studies

The first evaluation and mechanism studies of selone for palladium extraction.

Extraction of phenol from aqueous solutions by means of supported liquid membrane (MLS) containing tri-n-octyl phosphine oxide (TOPO)

This paper deals with the liquid-liquid extraction and the facilitated transport through a supported liquid membrane (SLM) system of aqueous phenol using tri-n-octyl phosphine oxide (TOPO) dissolved in an appropriate organic solvent. Phenol has been quantitatively extracted from aqueous acidic solutions using TOPO dissolved in kerosene as organic phase. The effect of TOPO concentration dissolved in kerosene on the extraction efficiency reveals that TOPO combined with phenol in the ratio of 1:1. Using a flat-sheet SLM (FSSLM) system, more than 65% of the initial phenol content in the feed phase was extracted and stripped in a NaOH aqueous receiving phase. The important operational variables affecting the facilitated transport of phenol through the FSSLM system studied are concentration of TOPO, membrane viscosity, feed phase pH, initial phenol concentration, polymeric support type and membrane stability. Regardless of its comparatively low extraction efficiency of phenol, the SLM based on TOPO exhibits higher long-term stability as compared to tributyl phosphate (TBP). Elaborated SLM system retained its stability and initial performance during the 5 days long experiment contrary to the TBP-SLM system where a time dependent negative tendency (transport efficiency decline) was observed.

Extraction of gold(III) from hydrochloric acid solutions by CTAB/n-heptane/iso-amyl alcohol/Na2SO3 microemulsion

The extraction of Au(III) from hydrochloric acid solutions by microemulsion was studied. The extraction experiments were carried out using cetyltrimethylammonium bromide (CTAB) as surfactant and iso-amyl alcohol as co-surfactant. Au(III) was found to be extracted into the microemulsion phase due to ion pair formation such as AuCl(4)(-)CTAB(+). The influence of temperature on the extraction of Au(III) has been investigated at temperatures ranging from 288 to 313 K. Temperature was found to decrease the distribution of Au(III). Thermodynamic parameters like enthalpy and entropy of the extraction, calculated by applying Van't Hoff equation, were -36.76 kJ mol(-1) and -84.87 J mol(-1) K(-1), respectively. Furthermore, the influence of the concentrations of hydrogen ion and chloride anion on the extraction efficiency (E%) were verified. Au(III) was extracted quantitatively (E%>99%) and selectively at the whole range of HCl concentrations (0.2-5 M). Recovery of gold from electrical waste and treatment of CTAB wastewater generated from the extraction were also discussed. Thus, the extraction of Au(III) from hydrochloric acid solutions by microemulsion is an effective approach.

Solid phase extraction of lead and cadmium using solid sulfur as a new metal extractor prior to determination by flame atomic absorption spectrometry

A new method using a mini-column packed with sulfur as a new solid phase extractor has been developed for simultaneous preconcentration of lead and cadmium in water samples prior to flame atomic absorption spectrometric determinations. The effects of various parameters such as pH, flow rate of sample and eluent, type and concentration of eluent, sample volume, amount of adsorbent and interfering ions have been studied. The calibration graph was linear in the range of 10-300 and 1-20 ng mL(-1) for lead and cadmium, respectively. The limit of detection based on three times the standard deviation of the blank (3S(b)) was 3.2 and 0.2 ng mL(-1) (n=10) for lead and cadmium, respectively. A preconcentration factor of 250 was achieved in this method. The proposed procedure was applied to the determination of metal ions in tap, river and wastewater samples.