Highly selective transport of silver ion through a supported liquid membrane using calix[4]pyrroles as suitable ion carriers

Liquid membranes for separation of metal ions from wastewaters

The paper reviews application of various liquid membranes (LM), particularly of emulsion and supported liquid membranes, for metal separation from model and industrial wastewaters. A variety of carriers and separation systems is shown. Not only model solutions on a laboratory scale are presented but also some examples of real wastewater separation with LM are reported.

A highly selective green supported liquid membrane by using a hydrophobic deep eutectic solvent for carrier-less transport of silver ions

A new supported liquid membrane (SLM) was designed by using a suitable deep eutectic solvent (DES) as the hydrophobic liquid membrane phase for the selective and facilitated carrier-less transport of Ag+ ions. The deep eutectic solvent was composed of a 4/1 molar ratio of l-menthol/salicylic acid and was impregnated into a microporous polypropylene membrane to prepare a novel carrier-less SLM system. The highly selective facilitated transport of silver ions was accomplished by using sodium thiosulfate as a highly selective stripping agent for Ag+ ions in the aqueous strip phase (SP). Some important factors, including the concentration of picric acid in the feed phase (FP), pH of the two aqueous phases, stirring rate, transport time, and nature and concentration of the stripping agent were also investigated and optimized. In the presence of 2.8 × 10-2 mol L-1 picrate ions as an appropriate ion pairing agent in the FP and 0.025 mol L-1 thiosulfate as a convenient metal ion acceptor in the SP, the amount of Ag+ ion transport found to occur almost quantitatively after 60 min is 90%. Compared with other SLM systems reported in the literature, the designed DES-SLM system exhibited suitable permeability and higher selectivity for Ag+ ion transport from aqueous solutions containing Fe2+, Mn2+, Cu2+, Ni2+, Pb2+, and Cd2+ as competing metal ions.

Selective Transport of Ag(I) through a Polymer Inclusion Membrane Containing a Calix[4]pyrrole Derivative from Nitrate Aqueous Solutions

Cellulose-triacetate-based polymer inclusion membranes (PIMs) with different concentrations of a calixpyrrole ester derivative as the membrane carrier were studied to determine their ability to transport Ag(I) from aqueous nitrate solutions. The effects of the concentrations of ion carriers and metal ions, the pH of the source aqueous phase, and stripping agents on the effective transport of Ag(I) were assessed. All studied parameters were found to be important factors for the transport of Ag(I) metal ions. The initial fluxes were determined at different temperatures. The prepared membranes were found to be highly permeable. The selectivity of silver transport from an aqueous solution containing Ag(I), Cu(II), Pb(II), Cd(II), Ni(II), Zn(II), and Co(II) ions was also investigated.

Application of Polymer Inclusion Membranes Doped with Alkylimidazole to Separation of Silver and Zinc Ions from Model Solutions and after Battery Leaching

New materials, such as polymer inclusion membranes, can be used for water and wastewater treatment. In this paper, the selective transport of silver(I) and zinc(II) ions from nitrate solutions through the polymer inclusion membranes (PIMs), which consist of cellulose triacetate as a polymeric support, o-nitrophenyl pentyl ether as a plasticizer, and either 1-hexylimidazole (1) or 1-hexyl-2-methylimidazole (2) as an ion carrier, is studied. Both Zn(II) and Ag(I) model solutions (CM = 0.001 M, pH = 6.5), as well as the solutions after the leaching of a spent battery with a silver-zinc cell (silver-oxide battery), are tested. The results show that Zn(II) ions are effectively transported through PIMs containing either carrier, whereas Ag(I) is more easily transported through PIMs doped with (1). In the case of the leaching solution after 24 h transport, the recovery coefficients of Ag(I) and Zn(II) for PIMs doped with (1) are 86% and 90%, respectively, and for PIMs doped with (2), 47% and 94%, respectively. The influence of basicity and structure of carrier molecules on transport kinetics is discussed as well. PIMs are characterized by using an atomic force microscopy (AFM) technique.

Selective removal of silver(i) using polymer inclusion membranes containing calixpyrroles

The transport of Ag(i) across polymer inclusion membranes is reported with derivatives of calixpyrroles with methyl (KP1) and carboxyl (KP2) groups as ion carriers, o-nitrophenyl pentyl ether as a plasticizer and cellulose triacetate as support.

Calix[4]arene derivative bearing imidazole groups as carrier for the transport of palladium by using bulk liquid membrane

The carrier activity of calix[4]arene containing imidazole groups towards the facilitated transport of palladium(II) through dichloromethane bulk liquid membrane has been studied. The optimum transport conditions were established by the studies on the effect of pH, feed concentration, carrier concentration, receiver phase concentration and transport time. A solution of 1M hydrochloric acid (HCl) served as receiving phase for maximum transport of the metal ion. Maximum transport efficiency was observed for Pd(II) ion when it was present in the concentration of 10(-3)M and the transport efficiency after 24h was found as 95%.

Thin layer porphyrinogen for alcohol-vapor optical sensors

Thin films of meso-octaethylporphyrinogen with different thickness were deposited on suitable substrates by Langmuir-Blodgett deposition technique in order to realize optical-sensitive active layers using Surface Plasmon Resonance (SPR) technique as transduction methodology. Analysis of the morphology of the sensing layers was performed by Atomic Force Microscopy. In particular, such coatings were tested for the detection of alcohol vapors such as ethanol, methanol and isopropanol. This resulted in a reversible shift in the resonance depth and angular position of the SPR curves, depending on the interactions between the sensing layers and the alcohol vapor molecules. Different sensitivity and rate of response for different alcohol molecules were found and analyzed. Measurements of the sensing response towards successive expositions of the sensing layers to methanol, ethanol and isopropanol vapors were performed in order to analyze the discrimination properties of the active layers towards the analytes.