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Maria Muñoz - One of the best experts on this subject based on the ideXlab platform.
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Zn(II), Cd(II) and Cu(II) separation through organic-inorganic Hybrid Membranes containing di-(2-ethylhexyl) phosphoric Acid or di-(2-ethylhexyl) Dithiophosphoric Acid as a carrier
Journal of Membrane Science, 2006Co-Authors: M. Resina, Jorge Macanás, J. De Gyves, Maria MuñozAbstract:A membrane process for metal recovery from aqueous solutions was studied. Metal ions diffused from the feed solution to the stripping phase through an Hybrid Membrane containing di-(2-ethylhexyl) phosphoric Acid (D2EHPA) and/or di-(2-ethylhexyl) Dithiophosphoric Acid (D2EHDTPA) as a carrier. Such membranes were prepared by a sol–gel route including cellulose triacetate and polysiloxanes. Transport behaviour was evaluated for both carriers under similar experimental conditions. The transport experiments reported here concerned transport at different cycles and selectivity towards different metal ions. Using D2EHPA the membrane provided a selective transport of zinc to the stripping compartment of the membrane cell, while copper and cadmium remained in the feed compartment. Whereas, using D2EHDTPA as carrier the transport rate increased and the selectivity profiles were inverted in relation with those of D2EHPA. With a mixture of both extracting agents it was observed an intermediate behaviour in selective transport, being possible to modulate it.
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Mass transfer determining parameter in facilitated transport through di-(2-ethylhexyl) Dithiophosphoric Acid activated composite membranes
Analytica Chimica Acta, 2005Co-Authors: Jorge Macanás, Maria MuñozAbstract:Activated composite membranes (ACMs) containing di-(2-ethylhexyl) Dithiophosphoric Acid (D2EHDTPA) as a carrier have been found to facilitate the transport and separation of several cations. This paper describes an approach to the chemical characterisation of the transport phenomena of Zn2+, Cd2+, Cu2+, Ni2+, Sn2+ and In3+ by an ACM. The selectivity of D2EHDTPA based ACM towards different metal ions is presented and discussed focusing in Zn2+ and Cd2+ transport and recovery. Selectivity demonstrates that zinc ions are removable from mixtures due to the different extraction strength of D2EHDTPA. Such selectivity is based on the differences of the dynamic behaviour of the metal ions transport. In addition, a correlation of the chemical behaviour of those ACM systems with the corresponding solvent extraction systems has been found.
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surface characterization of di 2 ethylhexyl Dithiophosphoric Acid activated composite membranes by x ray photoelectron spectroscopy
Surface and Interface Analysis, 2000Co-Authors: M. J. Ariza, Maria Muñoz, Rodrigo Rico, Juana Benavente, Enrique Rodriguezcastellon, Maria OleinikovaAbstract:Surface chemical characterization of a set of activated composite membranes containing different concentrations of di-(2-ethylhexyl)Dithiophosphoric Acid (DTPA) as carrier was performed by x-ray photoelectron spectroscopy (XPS). As a result of the addition of DTPA to the membrane samples, the N 1s signal intensities decrease, whereas the P 2p signal intensities increase with increasing carrier concentration. Upon Acid addition, the polyamide component of the membrane was protonated and a new peak at higher binding energies was observed in the N 1s XPS signal, due to the increase of the positive charge of these protonated nitrogen atoms. The S 2p signals indicate the coexistence of two contributions assigned to the presence of the Acid carrier ionically bonded to the protonated amide and to free Acid molecules.
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Surface characterization of di‐(2‐ethylhexyl)Dithiophosphoric Acid‐activated composite membranes by x‐ray photoelectron spectroscopy
Surface and Interface Analysis, 2000Co-Authors: M. J. Ariza, Maria Muñoz, Enrique Rodríguez-castellón, Rodrigo Rico, Juana Benavente, Maria OleinikovaAbstract:Surface chemical characterization of a set of activated composite membranes containing different concentrations of di-(2-ethylhexyl)Dithiophosphoric Acid (DTPA) as carrier was performed by x-ray photoelectron spectroscopy (XPS). As a result of the addition of DTPA to the membrane samples, the N 1s signal intensities decrease, whereas the P 2p signal intensities increase with increasing carrier concentration. Upon Acid addition, the polyamide component of the membrane was protonated and a new peak at higher binding energies was observed in the N 1s XPS signal, due to the increase of the positive charge of these protonated nitrogen atoms. The S 2p signals indicate the coexistence of two contributions assigned to the presence of the Acid carrier ionically bonded to the protonated amide and to free Acid molecules.
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Selective transport of zinc through activated composite membranes containing di(2-ethylhexyl)Dithiophosphoric Acid as a carrier
Polyhedron, 1999Co-Authors: Maria Oleinikova, Carlos León González, Manuel Valiente, Maria MuñozAbstract:Abstract The transport phenomena of transition metal cations through supported activated composite membrane (ACM) containing di-(2-ethylhexyl)Dithiophosphoric Acid (DTPA) as a carrier have been studied. The polyamide top layer of the ACM immobilizes DTPA by trapping it in the polymer net during the interfacial polymerization process. The comparison of ACM with the corresponding supported liquid membrane (SLM) shows far higher stability of the former. Thus, the results of a comparative study of SLM and ACM under identical conditions show that no metal ions transport through SLM is observed after 1 day working experiment, while ACM demonstrate sufficiently stable transport properties within several weeks of their use. A membrane-based process for zinc recovery from hydrometallurgical effluents has been developed. Zinc selectively diffuses from the feed solution through the ACM into the receiver solution containing 2.2 M hydrochloric Acid, due to the facilitated transport with DTPA acting as carrier in the membrane. The selectivity of DTPA based ACM towards different metal ions is presented and discussed. At pH 2 in the feed phase, the membrane provides a selective transport of zinc ionic species to the stripping compartment of the membrane cell, while other metal ions (Al, Ca, Mg, Mn and Ni) with sufficiently high stability of the DTPA-complexes remain in the feed compartment. Such a selectivity is based on the differences of the dynamic behaviour of the metal ions transport.
Praveen Kumar Mishra - One of the best experts on this subject based on the ideXlab platform.
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synthesis physicochemical characterization and biological activity of nanocomplexes of iron iii of 3 2 hydroxyphenyl 5 4 substituted phenyl pyrazolines and Dithiophosphoric Acid
Journal of Coordination Chemistry, 2014Co-Authors: U.n. Tripathi, Afshan Siddiqui, Kajal Singh, Shikha Vishwakarma, Praveen Kumar MishraAbstract:Complexes of iron(III) with Dithiophosphoric Acid and 3(2′-hydroxy phenyl)-5-(4-substituted phenyl) pyrazolines, [Fe(C6O14O2PS2)2(C15H12N2OX)], and [Fe(C6O14O2PS2)(C15H12N2OX)2], where (C6O14O2PS2H) = Dithiophosphoric Acid, (C15H13N2OX) = deprotonated 3(2′-hydroxy phenyl)-5-(4-substituted phenyl)pyrazolines (X = H, CH3, OCH3, Cl), have been synthesized. These complexes have been physicochemically characterized by elemental analysis (C, H, N, S, Cl, and Fe), magnetic moment data, thermogravimetric analysis, molar conductance, cyclic voltammetry, and spectral analysis (UV–visible, IR, and Fast atom bombardment mass spectrometry). Scanning electron microscopy, TEM, and PXRD have been carried out for powdered samples, which show nanometric particles of these derivatives. Antibacterial and antifungal potential of free pyrazoline and iron(III) complexes have been evaluated.
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Synthesis, physicochemical characterization, and biological activity of nanocomplexes of iron(III) of 3(2′-hydroxyphenyl)-5-(4-substituted phenyl) pyrazolines and Dithiophosphoric Acid
Journal of Coordination Chemistry, 2014Co-Authors: U.n. Tripathi, Afshan Siddiqui, Kajal Singh, Shikha Vishwakarma, Praveen Kumar MishraAbstract:Complexes of iron(III) with Dithiophosphoric Acid and 3(2′-hydroxy phenyl)-5-(4-substituted phenyl) pyrazolines, [Fe(C6O14O2PS2)2(C15H12N2OX)], and [Fe(C6O14O2PS2)(C15H12N2OX)2], where (C6O14O2PS2H) = Dithiophosphoric Acid, (C15H13N2OX) = deprotonated 3(2′-hydroxy phenyl)-5-(4-substituted phenyl)pyrazolines (X = H, CH3, OCH3, Cl), have been synthesized. These complexes have been physicochemically characterized by elemental analysis (C, H, N, S, Cl, and Fe), magnetic moment data, thermogravimetric analysis, molar conductance, cyclic voltammetry, and spectral analysis (UV–visible, IR, and Fast atom bombardment mass spectrometry). Scanning electron microscopy, TEM, and PXRD have been carried out for powdered samples, which show nanometric particles of these derivatives. Antibacterial and antifungal potential of free pyrazoline and iron(III) complexes have been evaluated.
Reinaldo C. De Campos - One of the best experts on this subject based on the ideXlab platform.
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On-line mercury and methylmercury pre-concentration by adsorption of their Dithiophosphoric Acid diacyl ester chelates on a C_18 column and cold-vapor atomic-absorption detection
Fresenius' Journal of Analytical Chemistry, 2001Co-Authors: Alcicléa Da C. P. Monteiro, Ly S. De Andrade, Reinaldo C. De CamposAbstract:The pre-concentration of mercury(II) and methylmercury by adsorption of their Dithiophosphoric Acid diacyl ester (DDTP) chelates on a C_18 column, then detection with cold-vapor atomic-absorption spectrometry was investigated. Conditions such as sample pH, reductant and chelating agent flow and concentration, and eluent and carrier gas flow were optimized. Optimization was performed by use of evolutionary operation with a proper factorial design. At a sample flow of 5.3 mL min^–1 and a loading time of 4.5 min, column adsorption efficiency ranged from 88 to 93% for both species. Detection limits down to 10 ng L^–1 were obtained at a sample throughput of 12 h^–1. There was good agreement between found and certified values in the analysis of certified reference materials after their microwave-assisted mineralization with HNO_3 and H_2O_2.
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On-line mercury and methylmercury pre-concentration by adsorption of their Dithiophosphoric Acid diacyl ester chelates on a C18 column and cold-vapor atomic-absorption detection
Fresenius' journal of analytical chemistry, 2001Co-Authors: Alcicléa Da Conceição Pereira Monteiro, Ly S. De Andrade, Reinaldo C. De CamposAbstract:The pre-concentration of mercury(II) and methylmercury by adsorption of their Dithiophosphoric Acid diacyl ester (DDTP) chelates on a C18 column, then detection with cold-vapor atomic-absorption spectrometry was investigated. Conditions such as sample pH, reductant and chelating agent flow and concentration, and eluent and carrier gas flow were optimized. Optimization was performed by use of evolutionary operation with a proper factorial design. At a sample flow of 5.3 mL min–1 and a loading time of 4.5 min, column adsorption efficiency ranged from 88 to 93% for both species. Detection limits down to 10 ng L–1 were obtained at a sample throughput of 12 h–1. There was good agreement between found and certified values in the analysis of certified reference materials after their microwave-assisted mineralization with HNO3 and H2O2.
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A study of the ditiophosphoric Acid diacylester as a masking agent for the determination of bismuth in the presence of copper by hydride generation atomic absorption spectrometry
Talanta, 2000Co-Authors: Iracema Takase, Reinaldo C. De CamposAbstract:Abstract The masking action of the Dithiophosphoric Acid diacylester (DDTP) for the determination of Bi by hydride generation absorption spectrometry (HGAAS) in the presence of high concentrations of copper was studied. Cu/Bi ratios up to 50×103 were found to be tolerable in the presence of 2×10−3 M chelating solutions in 10% HCl, using 1.5% NaBH4 as reductant. Good agreement between the certified values and those found in the present study was verified in the analysis of certified reference materials.
U.n. Tripathi - One of the best experts on this subject based on the ideXlab platform.
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synthesis physicochemical characterization and biological activity of nanocomplexes of iron iii of 3 2 hydroxyphenyl 5 4 substituted phenyl pyrazolines and Dithiophosphoric Acid
Journal of Coordination Chemistry, 2014Co-Authors: U.n. Tripathi, Afshan Siddiqui, Kajal Singh, Shikha Vishwakarma, Praveen Kumar MishraAbstract:Complexes of iron(III) with Dithiophosphoric Acid and 3(2′-hydroxy phenyl)-5-(4-substituted phenyl) pyrazolines, [Fe(C6O14O2PS2)2(C15H12N2OX)], and [Fe(C6O14O2PS2)(C15H12N2OX)2], where (C6O14O2PS2H) = Dithiophosphoric Acid, (C15H13N2OX) = deprotonated 3(2′-hydroxy phenyl)-5-(4-substituted phenyl)pyrazolines (X = H, CH3, OCH3, Cl), have been synthesized. These complexes have been physicochemically characterized by elemental analysis (C, H, N, S, Cl, and Fe), magnetic moment data, thermogravimetric analysis, molar conductance, cyclic voltammetry, and spectral analysis (UV–visible, IR, and Fast atom bombardment mass spectrometry). Scanning electron microscopy, TEM, and PXRD have been carried out for powdered samples, which show nanometric particles of these derivatives. Antibacterial and antifungal potential of free pyrazoline and iron(III) complexes have been evaluated.
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Synthesis, physicochemical characterization, and biological activity of nanocomplexes of iron(III) of 3(2′-hydroxyphenyl)-5-(4-substituted phenyl) pyrazolines and Dithiophosphoric Acid
Journal of Coordination Chemistry, 2014Co-Authors: U.n. Tripathi, Afshan Siddiqui, Kajal Singh, Shikha Vishwakarma, Praveen Kumar MishraAbstract:Complexes of iron(III) with Dithiophosphoric Acid and 3(2′-hydroxy phenyl)-5-(4-substituted phenyl) pyrazolines, [Fe(C6O14O2PS2)2(C15H12N2OX)], and [Fe(C6O14O2PS2)(C15H12N2OX)2], where (C6O14O2PS2H) = Dithiophosphoric Acid, (C15H13N2OX) = deprotonated 3(2′-hydroxy phenyl)-5-(4-substituted phenyl)pyrazolines (X = H, CH3, OCH3, Cl), have been synthesized. These complexes have been physicochemically characterized by elemental analysis (C, H, N, S, Cl, and Fe), magnetic moment data, thermogravimetric analysis, molar conductance, cyclic voltammetry, and spectral analysis (UV–visible, IR, and Fast atom bombardment mass spectrometry). Scanning electron microscopy, TEM, and PXRD have been carried out for powdered samples, which show nanometric particles of these derivatives. Antibacterial and antifungal potential of free pyrazoline and iron(III) complexes have been evaluated.
Lev Bromberg - One of the best experts on this subject based on the ideXlab platform.
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Structure of gels formed by modified poly(vinyl chloride) and Di(2‐ethylhexyl) Dithiophosphoric Acid
Journal of Applied Polymer Science, 1993Co-Authors: Gideon Levin, Lev Bromberg, Vlad BrumfeldAbstract:The structure of gels formed by dialkyldithio-substituted PVC and di(2-ethylhexyl)Dithiophosphoric Acid (DTPA) was investigated by monotoring the changes in the monomer/excimer emission ratio of pyrene introduced into the gels. The results obtained with different contents of the gels show that there is an agreement between the metal transfer rate through the gels depending on DTPA mobility and microviscosity compared with using pyrene. Changes in microviscosity could be explained by the rearrangement of intermolecular H-bonding in the gels
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Gelled membrane composed of dioctyldithiocarbamate substituted on poly(vinylchloride) and di (2‐ethylhexyl) Dithiophosphoric Acid
Journal of Applied Polymer Science, 1993Co-Authors: Gideon Levin, Lev BrombergAbstract:Substitution of chlorine of poly(vinylchloride) (PVC) by dioctyldithiocarbamate (DODTC) groups results in a modified polymer (MP) with a glass transition temperature of between −43 and 84°C, depending on the degree of substitution. Formation of a gelled membrane composed of MP and di (2-ethylhexyl) Dithiophosphoric Acid (DTPA), as both an ion carrier and a solvent, was demonstrated. The gelled membrane can be formed with the weight ratio between (MP) : (DTPA) as low as 1 : 99 or higher. The membrane is capable of selective separation of metal ions. © 1993 John Wiley & Sons, Inc.
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Extraction chromatography with modified poly(vinyl chloride) and di(2-ethylhexyl)Dithiophosphoric Acid
Journal of Chromatography A, 1993Co-Authors: Lev Bromberg, Gideon LevinAbstract:Abstract A method for the preparation of packed-bed columns made of gelled beads is described. The stable gelled beads composed of dialkyldithiocarbamate- or dialkyldithiophosphate-substituted poly(vinyl chloride) and di(2-ethylhexyl)Dithiophosphoric Acid were capable of the selective separation of metal ions. The stoichiometries of Ag+/H+ and Cd2+/H+ extraction were established to be 3:1 and 2:1, respectively. A simple model of Ag+ extraction kinetics was correlated with the experimental data. The selectivity of metal separations in displacement and elution chromatography was demonstrated.
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Membrane extraction of silver by di(2-ethylhexyl) Dithiophosphoric Acid
Journal of Membrane Science, 1992Co-Authors: Lev Bromberg, Isaak Lewin, Abraham WarshawskyAbstract:A membrane-based process for silver recovery from waste solutions was derived. Silver diffused from the feed solution through the supported liquid membrane containing di(2-ethylhexyl)Dithiophosphoric Acid (DTPA) as a carrier into the receiver solution, which contain thiourea at a low pH. Silver transfer rate and diffusion coefficient in the membrane were found to be up to 1.5 × 10-9 mol/cm2-sec and 2 × 10-6 cm2/sec, respectively. The membranes used demonstrated an ability to work in contact with waste solutions from silver reclamation eluants until silver had been transferred even against a very high concentration gradient. The dependencies of silver transfer rate on such factors as pH in the receiver and feed phases, DTPA and thiourea concentrations, were investigated.