Chemically active liquid membranes in inorganic supports for metal ion separations

Yi, Jongheop; Tavlarides, Lawrence L.

doi:10.1002/aic.690381211

Cited by 25 publications

(18 citation statements)

References 36 publications

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“…It is noteworthy that the high selectivity obtained for the monoenes (usually ≥99%) suggests that the selectivity is intrinsic to the Pd-metallic surfaces in this IL-hybrid organosilica environment, and probably, it is due to its highly electron deficient nature ( Table 1) that displays higher adsorption affinity for the diene than to the monoene. [63][64][65] This suggests that SILP/PdNPs under multiphase conditions (dynamic asymmetric mixture) 66 operates akin to catalytically active membranes 67 , i.e., far from thermodynamic equilibrium. 68 In this case, the dienes, which are at least four times more soluble in the hybrid catalytic materials than the monoenes 69,70 , displace the formed monoenes from the Pd-NP surface, which are then extracted by the organic phase (before reaching thermodynamic equilibrium).…”

Section: 61mentioning

confidence: 99%

Catalytically Active Membranelike Devices: Ionic Liquid Hybrid Organosilicas Decorated with Palladium Nanoparticles

et al. 2016

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Ionic liquid (IL)-hybrid organosilicas based on 1-n-butyl-3-(3-trimethoxysilylpropyl)-imidazolium cations associated with hydrophilic and hydrophobic anions decorated with well dispersed and similar sized (1.8-2.1 nm) Pd nanoparticles (PdNPs) are amongst the most active and selective catalysts for the partial hydrogenation of conjugated dienes to monoenes. The location of the sputter-imprinted Pd-NPs on different supports, as determined by RBS and HS-LEIS analysis, is modulated by the strength of the contact ion pair formed between the imidazolium cation and the anion, rather than the IL-hybrid organosilica pore size and surface area. In contrast, the pore diameter and surface area of the hybrid supports display a direct correlation with the anion hydrophobicity. XPS analysis showed that the Pd(0) surface component decreases with increasing ionic bond strength between the imidazolium cation and the anions (contact ion pair). The finding is corroborated by changes in the coordination number associated with the Pd-Pd scattering in EXAFS measurements. Hence, the interaction of the IL with the metal surface is found to occur via IL contact pairs (or aggregates). The observed selectivities of ≥99% to monoenes at full diene conversion indicate that the selectivity is intrinsic to the electron deficient Pd-metallic surfaces in this "restricted" ionic environment. This suggests that ILhybrid organosilica/Pd-NPs under multiphase conditions ("dynamic asymmetric mixture") operate akin to catalytically active membranes, i.e. far from the thermodynamic equilibrium. Detailed kinetic investigations show that the reaction rate is zero-order with respect to hydrogen and dependent on the fraction of catalyst surfaces covered by either the substrate and/or the product. The reaction proceeds via rapid inclusion and sorption of the diene to the IL/Pd metal surface saturated with H species. This is followed by reversible hydride migration to generate a π-allyl intermediate. The reductive elimination of this intermediate, the formal ratedetermining step (RDS), generates the alkene that is rapidly expelled from the IL phase to the organic phase.

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Section: 61mentioning

confidence: 99%

Catalytically Active Membranelike Devices: Ionic Liquid Hybrid Organosilicas Decorated with Palladium Nanoparticles

et al. 2016

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“…Teramoto and Tanimoto (1983) have used similar expressions for copper permeation through SME 529. The expressions for extraction and stripping were also verified by Yi and Tavlarides (1992) for copper permeation through LIX 84. The forward and reverse reaction rate constants obtained earlier by Haan et al (1989) are close to the values obtained by Yi and Tavalrides (1992).…”

Section: Modeling Of Copper Transportmentioning

confidence: 99%

“…At the strip solutionmembrane interface, the metal is back extracted and concentrated in the strip solution for recycle. Yi and Tavlarides (1992) have studied the kinetics of extraction and stripping of Cu2+ using the SLM configuration of the liquid ion exchanger in a porous ceramic support.…”

Section: Introductionmentioning

confidence: 99%

Heavy metal removal and recovery by contained liquid membrane permeator

et al. 1994

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“…Final copper concentration (mgll) Figure 2. The isothermal sorption curve of the oximemodified biomass for various pH conditions dissociate the bound copper from oxime just by decreasing the pH (Yi et al, 1992). Table 1 shows the affinity constant for copper ions.…”

Section: Introductionmentioning

confidence: 99%

Removal of copper using marine brown alga, Undaria Pinnatifida modified with oxime

et al. 1996

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As oxime is selective for CU'*, oxime groups were introduced to the cell wall of alga by glutaraldehyde. Such modified biomass showed high affinity for Ct?, which resulted in the increase of copper sorption capacity about 4.5 times higher than that of natural alga. For pH range from 2.5 to 3.0, only CL?' were removed by alga biomass modified with oxime, while other heavy metal ions such as Ca2',Cd2',Pb2' were not adsorbed. By changing pH, selective recovery of Cu2+ was achieved.

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Chemically active liquid membranes in inorganic supports for metal ion separations

Abstract: (Largman and Sifniades, 1978;Babcock et al., 1981;Teramoto and Tanimoto, 1983;Kojima and Miyauchi, 1981

Cited by 25 publications

References 36 publications

Catalytically Active Membranelike Devices: Ionic Liquid Hybrid Organosilicas Decorated with Palladium Nanoparticles

Catalytically Active Membranelike Devices: Ionic Liquid Hybrid Organosilicas Decorated with Palladium Nanoparticles

Heavy metal removal and recovery by contained liquid membrane permeator

Removal of copper using marine brown alga, Undaria Pinnatifida modified with oxime

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