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A polymeric membrane-supported catalyst with immobilized gold nanoparticles (AuNPs) was prepared through the extraction and in situ reduction of AuIII salts in a one-step strategy. Polymeric inclusion membranes (PIMs) and polymeric nanoporous membranes (PNMs) were tested as different membrane-support systems. Transport experiments indicated that PIMs composed of cellulose triacetate, 2-nitrophenyloctyl ether, and an aliphatic tertiary amine (Adogen 364 or Alamine 336) were the most efficient supports for AuIII extraction. The simultaneous extraction and reduction processes were proven to be the result of a synergic phenomenon in which all the membrane components were involved. Scanning electron microscopy characterization of cross-sectional samples suggested a distribution of AuNPs throughout the membrane. Transmission electron microscopy characterization of the AuNPs indicated average particle sizes of 36.7 and 2.9 nm for the PIMs and PNMs, respectively. AuNPs supported on PIMs allowed for >95.4 % reduction of a 0.05 mmol L−1 4-nitrophenol aqueous solution with 10 mmol L−1 NaBH4 solution within 25 min. [ABSTRACT FROM AUTHOR]

Polymer electrolyte membrane fuel cells (PEMFC) for hydrogen and methanol have attracted the attention of research groups for many years mainly because they are promising candidates for clean and renewable power sources. The most common commercial product used as PEM is Nafion®. However, certain limitations and high production costs stimulate the research of new materials. In this work, new hybrid proton-conducting membranes for PEMFC based on sulfonated poly(ether ether ketone) and an inorganic–organic polysiloxane phase were obtained with the objective of improving its mechanical, thermal, and chemical resistance properties. The hybrid membranes were prepared by dissolving the base polymer in DMSO and adding different amounts of the polysiloxane phase previously obtained from polydimethylsiloxane and a cross-linking agent (tetraethyl orthosilicate or phenyltrimetoxysilane). Membranes were characterized using infrared spectroscopy and thermal analysis. Macroscopic properties as water uptake, ion-exchange capacity, and proton conductivity were determined. The methanol permeabilities were in the range of 5.53 × 10−7 − 8.36 × 10−7 cm2/s, which is several times lower than that of Nafion®117 (1.55 × 10−6 cm2/s). The hybrid membranes with both cross-linkers also exhibited higher proton conductivity with respect to Nafion®117 (40 mS/cm) at 80°C and 90% relative humidity. [ABSTRACT FROM PUBLISHER]

Abstract: Polymer inclusion membrane transport of copper(II) in chloride and sulfate medium is studied using CTA (support), tris(2-n-butoxyethyl)phosphate (plasticizer), LIX® 84-I (carrier), and ethanol (additive). An optimization in the aqueous phases (pH, type of anions and buffer concentration) and membrane compositions (extractant and plasticizer concentrations) was performed and the efficiency factors (permeability, selectivity, and stability) of the system evaluated. It was observed that besides the improvement in metal ion flux and reduction in metal accumulation in the membrane by the incorporation of the additive in the casting solution, an increase in membrane stability is also attained. A transport model for the system in sulfate medium is proposed. Values for the aqueous and organic resistances (Δ a =104.7 and Δ o =108.0 sm−1, respectively), true organic diffusion coefficient and membrane diffusion coefficient of the Cu(II)–carrier complex in the membrane phase (D b,o =10−13 and D o =10−12.2 m2 s−1, respectively) were calculated assuming that a carrier–diffusion mechanism is mainly responsible for ion transport, as suggested for the transport profiles, and the value of the conditional extraction constant determined in an independent form by solid–liquid extraction experiments. A highly selective separation of Cu(II) from Zn(II) and Fe(III) was achieved as well. [Copyright &y& Elsevier]

The title compound, [AuBr(C6H11NS)]n, formed through an AuIII→AuI reduction process, presents a polymeric structure including Au chains with alternating Au-Au distances of 3.0898 (8) and 3.1181 (8) Å. The coordination geometry is best described on the basis of linear [AuBr(C6H11NS)] molecules, which are associated into a one-dimensional polymer via a common aurophilic interaction. [ABSTRACT FROM AUTHOR]

Polymer inclusion membranes containing cellulose triacetate as support, Ionquest® 801 ((2–ethylhexyl acid) -mono (2–ethylhexyl) phosphonic ester) as extractant, and 2NPOE (o–nitrophenyl octyl ether) or TBEP (tri (2–butoxyethyl phosphate)) as plasticizers were characterized using several instrumental techniques (Fourier Transform Infrared Spectroscopy (FT–IR), Reflection Infrared Mapping Microscopy (RIMM), Electrochemical Impedance Spectroscopy (EIS), Differential Scanning Calorimetry (DSC)) with the aim of determining physical and chemical parameters (structure, electric resistance, dielectric constant, thickness, components' distributions, glass transition temperature, stability) that allow a better comprehension of the role that the plasticizer plays in PIMs designed for In(III) transport. In comparison to TBEP, 2NPOE presents less dispersion and affinity in the PIMs, a plasticizer effect at higher content, higher membrane resistance and less permittivity, and a pronounced drop in the glass transition temperature. However, the increase in permittivity with In (III) sorption is more noticeable and, in general, PIMs with 2NPOE present higher permeability values. These facts indicate that In (III) transport is favored in membranes with chemical environment of high polarity and efficiently plasticized. A drawback is the decrease in stability because of the minor affinity among the components in 2NPOE–PIMs. [ABSTRACT FROM AUTHOR]

Abstract: The facilitated transport of lead(II) through polymeric inclusion membranes consisting of cellulose triacetate as polymeric support, bis-(2-ethylhexyl)-phosphoric acid (d2ehpa) as carrier, and tris-(2-butoxyethyl)phosphate as plasticiser (tbep), is investigated. The influence of some of the aqueous and membrane components on the permeability of Pb(II) was studied. The maximum flux obtained with these membranes is  mol m−2 s−1, which is of the same order of magnitude of those reported for supported liquid membranes and is in the upper range of those reported for polymeric inclusion membranes. Aqueous and membranes resistances were determined from a model that describes the transport mechanism across the membranes using the stoichiometric relationship and the extraction equilibrium constant value of determined independently by solid–liquid extraction. An activation energy of 11 kJ mol−1 was also determined for Pb(II) migration, which suggest that the transport of Pb(II) is controlled by a membrane diffusion mechanism. Membrane characterisation was performed using several techniques including atomic force microscopy, scanning electron microscopy coupled with energy-dispersive spectroscopy, and thermal analysis. [Copyright &y& Elsevier]

A polymeric membrane-supported catalyst with immobilized gold nanoparticles (AuNPs) was prepared through the extraction and in situ reduction of Au III salts in a one-step strategy. Polymeric inclusion membranes (PIMs) and polymeric nanoporous membranes (PNMs) were tested as different membrane-support systems. Transport experiments indicated that PIMs composed of cellulose triacetate, 2-nitrophenyloctyl ether, and an aliphatic tertiary amine (Adogen 364 or Alamine 336) were the most efficient supports for Au III extraction. The simultaneous extraction and reduction processes were proven to be the result of a synergic phenomenon in which all the membrane components were involved. Scanning electron microscopy characterization of cross-sectional samples suggested a distribution of AuNPs throughout the membrane. Transmission electron microscopy characterization of the AuNPs indicated average particle sizes of 36.7 and 2.9 nm for the PIMs and PNMs, respectively. AuNPs supported on PIMs allowed for >95.4 % reduction of a 0.05 mmol L -1 4-nitrophenol aqueous solution with 10 mmol L -1 NaBH 4 solution within 25 min., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Polymer inclusion membranes (PIMs) based on cellulose triacetate (CTA) and dibutyl butyl phosphonate (DBBP) were tested for arsenic(V) separation from H2SO4 for its recovery from copper electrolytes. Solvent extraction experiments allowed the determination of the As(V)-DBBP and H2SO4-DBBP complexes formed in the organic phase. Application of a transient model to membrane transport experiments in solutions containing only arsenic or H2SO4 indicated that it occurred under a kinetically controlled regime by formation of H3AsO4[DBBP]2 and H2SO4[DBBP] species, respectively. When arsenic and H2SO4 are simultaneously present, the existence of a third species, H3AsO4[DBBP][H2SO4], explains well the fact that As(V) flux decreases and that H2SO4 flux increases. In both cases, a limiting 50% recovery value was obtained. However, active arsenic transport (>50%) is achieved if the H2SO4 concentration gradient is assured (e.g., using a triple-cell configuration). In this way, high arsenic recovery factors (90% in 800 min) were obtained with initial concentrations of 5000 mg/L As(V) and 220 g/L H2SO4. In all membrane systems tested, good As(V) selectivity over copper (up to 30000 mg/L) was attained.