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Lamb, John D.; Christenson, Mark D.

doi:10.1023/a:1008098907781

Cited by 19 publications

(9 citation statements)

References 4 publications

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“…The molecular modeling of the bisaldehyde ligand shows that all bond lengths in the left and right hand sides are typical due to the similarity of moieties on the two sides. It is considered as symmetrical structure and all bond angles predict sp 3 and sp 2 hybridization confirming the structure. The data were obtained using Chem3D ultra 8.0 software program.…”

Section: Molecular Modelingmentioning

confidence: 57%

“…The thermodynamic activation parameters of decomposition processes of the complexes are calculated by employing the Coats-Redfern relation 43 and the data are summarized in Table (3). The high values of the activation energies reflect the thermal stability of the complexes.…”

Section: Calculation Of Activation Thermodynamic Parametersmentioning

confidence: 99%

“…The design and application of new macrocyclic receptors capable of constitutional coordination of guest molecules and ions, had attracted a great deal of interest as these systems had many potential functions such as solubilization, extraction, membrane transport [1][2][3][4][5][6] with applications in separation, chromatography, electrochemistry and spectrophotometric methods [7][8][9] . New strategies in the design and synthesis of novel functionalized macrocyclic receptors capable of selforganization and self-assembly [10][11][12][13][14] had been developed with the hope of improving the recognition and selective transport functions [15][16] .…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and characterization of bisaldehyde ligand with some transition metals and its application in spectrophotometric determination of Fe(III) in natural water samples using recovery test

2012

Egyptian Journal of Pure and Applied Science

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The coordination behaviour of the bisaldehyde organic ligand with different coordination sites are investigated, towards some bi-and trivalent metal ions like Cr(III), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II). The solid chelates of the bisaldehyde are prepared and subjected to many analytical techniques such as elemental analyses, IR, 1 H NMR and solid reflectance spectra, magnetic moment, molar conductance, X-Ray diffraction (XRD) and thermal analyses. The chelates have octahedral geometry. The bisaldehyde ligand and its binary chelates were subjected to thermal analyses and the different activation thermodynamic parameters were calculated from their corresponding DTG curves. The biological activity of the bisaldehyde ligand and its complexes were also screened. The bisaldehyde ligand is utilized for spectrophotometric determination of spiked Fe(III) in natural water samples using recovery test under optimal experimental conditions.

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Section: Molecular Modelingmentioning

confidence: 57%

Section: Calculation Of Activation Thermodynamic Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis and characterization of bisaldehyde ligand with some transition metals and its application in spectrophotometric determination of Fe(III) in natural water samples using recovery test

2012

Egyptian Journal of Pure and Applied Science

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“…For decades, chemists have been studying bulk liquid membrane systems which have the capacity to separate, purify, and concentrate solute in a relatively simple, efficient, and low-energy manner. − In a typical liquid membrane system (in contrast to a biomembrane or synthetic bilayer membrane), two batch solutions are separated by a thin immiscible liquid membrane. One of the batch solutions, called the feed , is enriched in a solute of interest, while the other, called the sweep , is dilute.…”

Section: Introductionmentioning

confidence: 99%

Simulations of Photopumping in Doubly Illuminated Liquid Membranes Containing Photoactive Carriers

2010

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A steady-state model used to simulate photofacilitated active transport against a concentration gradient, called photopumping, is described. Central to this model is the idea that the carrier can be in either a strongly binding or a weakly binding form and light can be used to control the interconversion rate between the two forms. Most experimental and theoretical studies have focused on systems in which only one side of the membrane is illuminated at a time to form singly illuminated liquid membranes. This study explores membranes in which both the feed and the sweep side are illuminated simultaneously with light of different wavelengths to form doubly illuminated liquid membranes. Doubly illuminated liquid membranes can sustain transport against concentration gradients in which the solute concentration in the sweep is a factor of 10 or more higher than that in the feed, while transport in singly illuminated liquid membranes falls off at lower concentration gradients. In addition, carrier properties that are important in single illumination such as the interconversion rates between the weakly and the strongly binding forms of the carrier are not important for doubly illuminated membranes, meaning that the range of suitable carriers will be much greater for double illumination than for single illumination.

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“…The affinity of macrocyclic crown ethers for specific cations is well known (14)(15)(16)(17). Those cations with ionic radii most closely matching the dimensions of the cavity of the macrocycle will be selectively complexed.…”

Section: Introductionmentioning

confidence: 99%

Comparison of supported liquid membranes and solid-phase extraction for quantitative removal of lead from aqueous solutions

Yourd¹,

Tyson²

2003

Can. J. Chem.

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The selective transport of a target metal ion across a membrane from a donor to an acceptor solution is an attractive concept for preconcentration or separation in a flow injection (FI) system. However, we found that the transport of lead across a supported liquid membrane consisting of dicyclohexano-18-crown-6 in decanol embedded in Celgard 2400 was too slow to be practical for an FI atomic spectrometry system. On the other hand, the same chemistry in an on-line, solid-phase reactor (a mini-column containing Pb-Spec resin) gave a satisfactory performance. In an attempt to understand the kinetics of the system, we have calculated the rate of transport across the membrane. As flux is proportional to concentration on the donor side -which decreases with time -we performed a series of numerical simulations involving fixed time intervals of decreasing values. These calculations show that for the sizes of membranes in a typical FI system, transport is very slow compared with the adsorption of lead by the Pb-Spec resin: it takes about 100 min for the concentration in a 0.06 mL donor solution to decrease by a factor of 1000. The time required for the same decrease in concentration for a membrane having the same surface area and ligand concentration as the Pb-Spec column was calculated as approximately 9 s.Key words: supported liquid membrane, solid-phase extraction, flow-injection, lead. Résumé :Le transport sélectif d'un ion métallique cible à travers une membrane à partir d'un donneur vers une solution accepteuse est un concept attrayant pour la préconcentration ou la séparation dans un système à injection continue (IC). Cependant, nous avons trouvé que le transport du plomb à travers une membrane liquide incrustée dans un support, cette membrane est constituée de dicyclohexano-18-couronne-6 dans le décanol incorporé dans du Celgard 2400, est trop lent pour être pratique dans un système de spectrométrie atomique à injection continue (IC). Par ailleurs la même chimie en continu dans un réacteur en phase solide (une mini colonne contenant une résine Pb-Spec), a donné une performance satisfaisante. Dans une tentative pour comprendre la cinétique du système, nous avons calculé la vitesse de transport à travers la membrane. Comme le flux est proportionnel à la concentration du côté du donneur, laquelle diminue avec le temps, nous avons réalisé une série de simulations numériques impliquant des intervalles de temps fixes de valeurs décroissantes. Ces calculs montrent que, compte tenu des dimensions des membranes dans un système typique à injection continue, le transport est très lent comparativement à l'adsorption du plomb par la résine Pb-Spec; il faut environ 100 minutes pour que la concentration dans 0,06 mL d'une solution donneuse décroisse d'un facteur de 1000. Le temps requis pour la même diminution de concentration dans le cas d'une membrane ayant la même superficie et la même concentration de ligand dans une colonne de Pb-Spec est selon les calculs approximativement de 9 s.

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Untitled

Cited by 19 publications

References 4 publications

Synthesis and characterization of bisaldehyde ligand with some transition metals and its application in spectrophotometric determination of Fe(III) in natural water samples using recovery test

Synthesis and characterization of bisaldehyde ligand with some transition metals and its application in spectrophotometric determination of Fe(III) in natural water samples using recovery test

Simulations of Photopumping in Doubly Illuminated Liquid Membranes Containing Photoactive Carriers

Comparison of supported liquid membranes and solid-phase extraction for quantitative removal of lead from aqueous solutions

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