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A Goswami - One of the best experts on this subject based on the ideXlab platform.
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nernst planck approach based on non steady state flux for transport in a Donnan Dialysis process
Journal of Membrane Science, 2016Co-Authors: Chhavi Agarwal, A GoswamiAbstract:Abstract In the present work, Nernst Planck (NP) approach based on non-steady state flux has been explored to predict the transport kinetics in a Donnan Dialysis process. The calculations have been carried out for pure and mixed bi-ionic monovalent–monovalent systems. Appropriate forms of the equations have been derived and then solved numerically by finite difference method using appropriate initial and boundary conditions. The results of the calculations have been compared with the experimental transport profiles and NP calculations based on pseudosteady state approximation. It has been found that the NP method based on non-steady state flux is capable of predicting the transport kinetics for both pure and mixed ionic systems for all salt compositions. On the other hand, NP approach based on pseudosteady state approximation works only at high salt concentrations (>0.1 M) for pure ionic systems. Also, the approach completely fails for mixed ionic systems. The NP approach with non-steady state flux is capable of accounting the accumulation of ions in the membrane and the time lag characteristics prevalent dominantly in the initial time scales of a membrane transport process.
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kinetic aspects of Donnan Dialysis through nafion 117 membrane
Journal of Membrane Science, 2012Co-Authors: Chhavi Agarwal, Sanhita Chaudhury, A K Pandey, A GoswamiAbstract:Abstract The transport rate of ions across Nafion-117 ion-exchange membrane in a Donnan Dialysis process has been measured for mono–monovalent (Na + –Cs + ) and mono–bivalent (Na + –Ba 2+ , Na + –Mg 2+ ) ion-exchange process. This has been carried out for different salt concentrations (0.01 M, 0.1 M and 0.5 M). The transport rate has also been calculated using appropriate form of Nernst–Planck equation. The self-diffusion coefficients of the ions and the ion-exchange capacity of the membrane have been given as input parameters in the calculations. The concentration of ions at the solution/membrane interface has been obtained from solution concentrations by the use of Donnan relation. The calculated time profile has been found to match with the experimental time profile at 0.1 M and 0.5 M salt concentrations. At 0.01 M concentration, there is significant deviation between the two profiles, probably showing the change in selectivity of the membrane with decrease in salt concentration. The experimental and the NP calculations have been compared with the calculations based on mass balance approach as given by Miyoshi (1996, 1997, 1998) [17–19] . The NP calculations coupled with the experimental time profile, have been used to obtain the self-diffusion coefficient of Mg 2+ ion in Nafion-117 membrane.
Esin Karamizrak - One of the best experts on this subject based on the ideXlab platform.
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preparation and characterization of p2fan pvdf composite cation exchange membranes for the removal of cr iii and cu ii by Donnan Dialysis
Reactive & Functional Polymers, 2010Co-Authors: Tugba Sardohan Koseoglu, Sabriye Percin Ozkorucuklu, Esin KaramizrakAbstract:Abstract In this work, poly(2-fluoroaniline) (P2FAn) was chemically synthesized with different dopant anions such as p-toluenesulfonate (PTS), 1,3 (6 or 7)-naphthalene trisulfonic acid (NSA), o-aminobenzen sulfonic acid (ABS), sodium dodecyl sulfate (SDS). The P2FAn/PVDF composite cation-exchange membranes were obtained from prepared poly(2-fluoroaniline) by casting method. These membranes were used for the removal of chromium (III) and copper (II) ions from aqueous solution with Donnan Dialysis (DD) experiments. The change of surface morphologies of the P2FAn/PVDF composite cation-exchange membranes were investigated by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The membrane thickness and their ion-exchange capacities were also measured. The flux values ( J ) and recovery factor (RF) of chromium (III) and copper (II) were obtained. The flux value of Cu(II) ion was higher than Cr(III) for all of composite membranes because of the hydration volume.
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Preparation and characterization of P2FAn/PVDF composite cation-exchange membranes for the removal of Cr(III) and Cu(II) by Donnan Dialysis
Reactive & Functional Polymers, 2010Co-Authors: Tugba Sardohan Koseoglu, Sabriye Percin Ozkorucuklu, Esin KaramizrakAbstract:Abstract In this work, poly(2-fluoroaniline) (P2FAn) was chemically synthesized with different dopant anions such as p-toluenesulfonate (PTS), 1,3 (6 or 7)-naphthalene trisulfonic acid (NSA), o-aminobenzen sulfonic acid (ABS), sodium dodecyl sulfate (SDS). The P2FAn/PVDF composite cation-exchange membranes were obtained from prepared poly(2-fluoroaniline) by casting method. These membranes were used for the removal of chromium (III) and copper (II) ions from aqueous solution with Donnan Dialysis (DD) experiments. The change of surface morphologies of the P2FAn/PVDF composite cation-exchange membranes were investigated by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The membrane thickness and their ion-exchange capacities were also measured. The flux values ( J ) and recovery factor (RF) of chromium (III) and copper (II) were obtained. The flux value of Cu(II) ion was higher than Cr(III) for all of composite membranes because of the hydration volume.
Chhavi Agarwal - One of the best experts on this subject based on the ideXlab platform.
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nernst planck approach based on non steady state flux for transport in a Donnan Dialysis process
Journal of Membrane Science, 2016Co-Authors: Chhavi Agarwal, A GoswamiAbstract:Abstract In the present work, Nernst Planck (NP) approach based on non-steady state flux has been explored to predict the transport kinetics in a Donnan Dialysis process. The calculations have been carried out for pure and mixed bi-ionic monovalent–monovalent systems. Appropriate forms of the equations have been derived and then solved numerically by finite difference method using appropriate initial and boundary conditions. The results of the calculations have been compared with the experimental transport profiles and NP calculations based on pseudosteady state approximation. It has been found that the NP method based on non-steady state flux is capable of predicting the transport kinetics for both pure and mixed ionic systems for all salt compositions. On the other hand, NP approach based on pseudosteady state approximation works only at high salt concentrations (>0.1 M) for pure ionic systems. Also, the approach completely fails for mixed ionic systems. The NP approach with non-steady state flux is capable of accounting the accumulation of ions in the membrane and the time lag characteristics prevalent dominantly in the initial time scales of a membrane transport process.
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Donnan Dialysis based separation of gold(III) from electronic waste solutions using an anion exchange pore-filled membrane
Journal of Membrane Science, 2016Co-Authors: Chhavi Agarwal, Robert W. Cattrall, Spas D. KolevAbstract:Donnan Dialysis technique was employed for the recovery of Au(III) from aqua regia solutions of electronic waste containing low concentrations of Au(III) in the presence of much higher concentrations of Cu(II) and Ni(II). The anion exchange pore-filled membrane was synthesized using in-situ photo-polymerization with polypropylene as the host membrane and (3-acrylamidopropyl)trimethyl ammonium chloride and (3-acryloxy-propyl)trimethoxysilane as the monomer and spacer, respectively. Photo-polymerization was carried out with ethylene glycol dimethacrylate as the cross-linker and 2,2-dimethoxy-2-phenyl acetophenone as the UV-initiator. The transport of Au(III) through this anion-exchange pore-filled membrane was studied using a two compartment cell where the receiver solution contained NaCl as the stripping reagent. Cu(II), which is the dominant metal ion in electronic waste solutions, did not interfere with the transport of Au(III) even at Au(III): Cu(II) mass ratios of up to 1:500. Gold from 100-fold diluted electronic waste solutions in aqua regia was successfully recovered (96.3%) after 4 cycles of Au(III) transport while at the same time insignificant fractions of the dominant metals in the electronic scrap (Cu and Ni) were transported. This study shows that Au(III) can be selectively recovered from diluted aqua regia solutions of electronic waste based on the proposed Donnan Dialysis process.
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kinetic aspects of Donnan Dialysis through nafion 117 membrane
Journal of Membrane Science, 2012Co-Authors: Chhavi Agarwal, Sanhita Chaudhury, A K Pandey, A GoswamiAbstract:Abstract The transport rate of ions across Nafion-117 ion-exchange membrane in a Donnan Dialysis process has been measured for mono–monovalent (Na + –Cs + ) and mono–bivalent (Na + –Ba 2+ , Na + –Mg 2+ ) ion-exchange process. This has been carried out for different salt concentrations (0.01 M, 0.1 M and 0.5 M). The transport rate has also been calculated using appropriate form of Nernst–Planck equation. The self-diffusion coefficients of the ions and the ion-exchange capacity of the membrane have been given as input parameters in the calculations. The concentration of ions at the solution/membrane interface has been obtained from solution concentrations by the use of Donnan relation. The calculated time profile has been found to match with the experimental time profile at 0.1 M and 0.5 M salt concentrations. At 0.01 M concentration, there is significant deviation between the two profiles, probably showing the change in selectivity of the membrane with decrease in salt concentration. The experimental and the NP calculations have been compared with the calculations based on mass balance approach as given by Miyoshi (1996, 1997, 1998) [17–19] . The NP calculations coupled with the experimental time profile, have been used to obtain the self-diffusion coefficient of Mg 2+ ion in Nafion-117 membrane.
Hirofumi Miyoshi - One of the best experts on this subject based on the ideXlab platform.
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Donnan Dialysis with ion exchange membranes iii diffusion coefficients using ions of different valence
Separation Science and Technology, 1999Co-Authors: Hirofumi MiyoshiAbstract:Donnan Dialysis with ion-exchange membranes was studied under various kinds of experimental conditions using ions of different valences. The diffusion coefficients (D d) of various kinds of ions in the ion-exchange membrane were obtained by curve fitting an equation derived from the mass balance to three kinds of Donnan dialytic experiments. It was found that the value of D d/D s using D d of monovalent ions in Donnan Dialysis with a set of monovalent feed ions and bivalent driving ions was 1/175, where D s represents a diffusion coefficient in solution. D s was calculated from the Nernst-Einstein equation substituted by the ionic conductance of ions at infinite dilution in water. Using D d of bivalent ions in Donnan Dialysis with the same set led to a D d/D s value of 1/438. Moreover, using D d in Donnan Dialysis with the same set, the value of D d/D e was kept constant at 0.4 (D e expresses the diffusion coefficient in the membrane when the valences of the feed and driving ions are equal). On the other ...
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diffusion coefficients of ions through ion excange membrane in Donnan Dialysis using ions of different valence
Journal of Membrane Science, 1998Co-Authors: Hirofumi MiyoshiAbstract:Abstract Donnan Dialysis with an ion exchange membrane was investigated for ions of different valence. The effective diffusion coefficients (De) of various kinds of ions in the membrane were obtained by fitting of the equation derived from the Nernst–Planck equation to three or more sets of experimental data for Donnan Dialysis. It became apparent that the value of De/Ds of monovalent ions (e.g., K+ or Na+ ions) at zA=1 and zB=2 (feed ions are monovalent ones and driving ions are bivalent ones) remained constant at ca. 1/210 and that of bivalent ions (e.g., Ca2+, Cu2+, or Mg2+ ions) remained constant at ca. 1/526 where Ds denotes the diffusion coefficient of ions at infinite dilution in water calculated from the Nernst–Einstein equation, and zA and zB represent the valences of the feed and driving ions, respectively. De/Ds of monovalent ions (e.g., H+, K+, or Na+ ions) at zA=2 and zB=1 (feed ions are bivalent ones and driving ions are monovalent ones) was constant at ca. 1/23.3 and that of bivalent ions remained constant at ca. 1/58.4. It was proved that De/D using De at zA=1 and zB=2 was constant at 1/3.0 and that at zA=2 and zB=1 remained constant at 3.0 where D represents the diffusion coefficient of ions in the membrane at zA=zB (the valences of both feed and driving ions are equal). Therefore, it was found that a large flux of ions could be obtained using the monovalent driving ions in Donnan Dialysis. On the other hand, the small flux can be obtained using bi- or higher-valent driving ions.
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diffusion coefficients of ions through ion exchange membranes for Donnan Dialysis using ions of the same valence
Chemical Engineering Science, 1997Co-Authors: Hirofumi MiyoshiAbstract:The transfer of ions through an ion-exchange membrane during Donnan Dialysis was studied theoretically and experimentally. By applying the Nernst-Planck equation to the flux of ions in the ion-exchange membrane, an equation was derived for Donnan Dialysis in which feed ions and driving ions were of equal valence. The theoretically derived equation was fitted to the experimental values by adjusting diffusion coefficients. Thus, the diffusion coefficients of ions in the ion-exchange membrane which satisfied all the experimental data were determined. It was clearly shown that the ratio of the diffusion coefficient in the membrane to that in solution remained constant at 70 for a system of monovalent feed and monovalent driving ions, and remained constant at 175 for a system of bivalent feed and bivalent driving ions. The flux of ions in Donnan Dialysis was found to be influenced by the concentrations of both feed ions and driving ions. Monovalent ions showed a larger flux than bivalent ions, suggesting that they were better as driving ions. The flux of ions was scarcely affected by the kinds of co-ions. It was necessary to pretreat the membrane with driving ions.
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Donnan Dialysis with ion exchange membranes i theoretical equation
Separation Science and Technology, 1996Co-Authors: Hirofumi MiyoshiAbstract:Abstract The transfer of ions through ion-exchange membranes was investigated theoretically for Donnan Dialysis. By applying Fick's equation and no electric current to the flux through the ion-exchange membrane on Donnan Dialysis, and by changing the valences of feed and drive ions, three kinds of equations were derived: 1) feed ions and drive ions are of equal valence, 2) feed ions are monovalent and drive ions are bivalent, and 3) feed ions are bivalent and drive ions are monovalent. The equations were evaluated by use of a computer by the Runge-Kutta method. The relation between the valence of ions and the characteristic coefficients of the membrane became apparent from the calculated results.
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Donnan Dialysis with ion exchange membranes ii diffusion coefficients using same valence ions
Separation Science and Technology, 1996Co-Authors: Hirofumi Miyoshi, Masayuki YamagamiAbstract:Abstract Donnan Dialysis with ion-exchange membranes was investigated experimentally. The equation derived theoretically in the previous paper was fitted to the results of a Donnan dialytic experiment, and the diffusion coefficients of various kinds of ions and in various kinds of ion-exchange membranes were obtained. The flux of monovalent ions in Donnan Dialysis was much larger than that of bivalent ions. Thus, monovalent drive ions are the best kind of drive ions to employ. It was found that the ratio of the diffusion coefficient in the ion-exchange membrane to that in the solution remained constant at 70 for monovalent feed and drive ions except for H+ ions, and at 175 for bivalent feed and drive ions. It became apparent that the fundamental equation derived from Fick's equation and no electric current might be used for Donnan Dialysis instead of the Nernst-Planck equation.
Claude Gavach - One of the best experts on this subject based on the ideXlab platform.
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fluoride removal from diluted solutions by Donnan Dialysis with anion exchange membranes
Desalination, 1999Co-Authors: Mustapha Hichour, Francoise Persin, Jacqueline Sandeaux, Jean Molenat, Claude GavachAbstract:Too many or too few fluoride ions in drinking water are harmful to the consumer's health. The acceptable fluoride concentration is generally in the range of 0.5 to 1.5 mg.L−1. In the present study, Donnan Dialysis (DD) with an anion-exchange membrane (AEM) was applied for the defluoridation of diluted NaF solutions. The initial concentration of the feed solution was maintained at 10−3 mol.L−1, corresponding to a 19 mg.L−1 fluoride concentration. Five kinds of AEMs (DSV, AFX, AFN, AMX, ACS) were tested. First, membrane properties were studied at equilibrium. The values of the exchange capacity of the membranes in Cl− and F− form, water content, selectivity coefficient for the Cl−F− exchange, diffusion coefficient of Cl− and F− ions in the membrane, were determined for each membrane. DD experiments, performed using a laboratory cell, showed that the DSV membrane is the most effective AEM, despite its electrolyte leakage. Subsequently, a pre-industrial pilot with a total membrane area of 1760 cm2 was used to study the different physico-chemical and hydrodynamic parameters of the process. As the driving ion, the chloride ion is more efficient than the sulfate ion. At flow rates lower than 0.6 L.h−1, the fluoride concentration remains lower than the permitted values despite the presence of others anions generally present in ground water such as chloride, sulfate and bicarbonate ions.
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fluoride removal from waters by Donnan Dialysis
Separation and Purification Technology, 1999Co-Authors: Mustapha Hichour, Francoise Persin, Jacqueline Sandeaux, Claude GavachAbstract:Abstract Excess or lack of levels of fluoride in drinking water being harmful to human health, the concentration of F − ions must be maintained in the range 0.5 to 1.5 mg l −1 . The purpose of this study is to apply Donnan Dialysis (DD) for fluoride removal from waters with a concentration exceeding the permitted value. Two synthetic waters, which are models of waters from countries of Africa (Maghreb, Senegal), were prepared and treated with a DD pre-industrial pilot. The anion exchange membrane was the DSV membrane (Asahi Glass), with a total area of 0.176 m 2 . The initial fluoride concentration was 9.5 and 6.1 mg l −1 in each model water, respectively. The DD process was studied under two circulating modes of the receiver solution, single pass and batch, while the feed solution flowed continuously as a single pass. To maintain the fluoride concentration below the acceptable values at the outlet of the feed compartment, the extracted fluoride ions are complexed by Al 3+ ions which were added in the receiver solution. Chemical speciation of aluminum–fluoride compounds was studied in order to define the optimized conditions of pH and concentration. Despite the different anions (Cl − , HCO − 3 , SO 2− 4 ) and cations (Na + , K + , Ca 2+ , Mg 2+ ) generally present in ground waters, a fluoride concentration in agreement with the norm ( −1 ) could be reached whatever the water treated. However, the mineralization of water was increased by about 25% resulting from the electrolyte diffusion which occurs from the receiver to the feed solution.
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transport and separation of ag and zn 2 by Donnan Dialysis through a monovalent cation selective membrane
Talanta, 1998Co-Authors: A T Cherif, Claude Gavach, Jean Molenat, Azzedine ElmidaouiAbstract:Abstract Donnan Dialysis of Ag+ and Zn2+ was investigated through a cation exchange membrane (CMS Neosepta) when a proton concentration difference was maintained between the two sides of the membrane. Developed for the production of brine from sea water, CMS Neosepta showed a higher permeability to monovalent than to bivalent cations. Several physico-chemical parameters have been determined (electrical resistance, membrane potential, sorption of electrolytes, Zn2+ and Ag+ diffusion coefficients). The flux of Ag+ and the diffusion potential in the membrane increase with HNO3 concentrations. Ag+ and Zn2+ can be separated because of the preferential membrane transfer for Ag+.
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Transport and separation of Ag(+) and Zn(2+) by Donnan Dialysis through a monovalent cation selective membrane.
Talanta, 1998Co-Authors: A T Cherif, Claude Gavach, Jean Molenat, Azzedine ElmidaouiAbstract:Abstract Donnan Dialysis of Ag+ and Zn2+ was investigated through a cation exchange membrane (CMS Neosepta) when a proton concentration difference was maintained between the two sides of the membrane. Developed for the production of brine from sea water, CMS Neosepta showed a higher permeability to monovalent than to bivalent cations. Several physico-chemical parameters have been determined (electrical resistance, membrane potential, sorption of electrolytes, Zn2+ and Ag+ diffusion coefficients). The flux of Ag+ and the diffusion potential in the membrane increase with HNO3 concentrations. Ag+ and Zn2+ can be separated because of the preferential membrane transfer for Ag+.