Self-diffusion coefficients of sodium ion in aqueous sodium polyacrylate solutions containing sodium chloride

1973 ◽  
Vol 77 (22) ◽  
pp. 2684-2687 ◽  
Author(s):  
Daniel S. Dixler ◽  
Paul Ander
Keyword(s):  
Sodium Chloride ◽  
Diffusion Coefficients ◽  
Sodium Ion ◽  
Sodium Polyacrylate ◽  
Aqueous Sodium ◽  
Self Diffusion

Self-Diffusion of Sodium, Chloride and Iodide Ions in Methanol-Water Mixture

1986 ◽  
Vol 41 (7) ◽  
pp. 939-943 ◽  
Author(s):  
E. Hawlicka
Keyword(s):  
Sodium Chloride ◽  
Diffusion Coefficients ◽  
Solvent Composition ◽  
The Self ◽  
Water Mixture ◽  
Preferential Hydration ◽  
Water Solutions ◽  
Iodide Ions ◽  
Self Diffusion

The self-diffusion coefficients of Na+, Cl- and I- in methanol-water solutions at 35 ± 0.01 °C have been measured in their dependence on the salt molarity in the range 1 · 10-4- 1 · 10-2 mol dm -3. The ionic self-diffusion coefficients in infinitely diluted solutions have been computed. The influence of the solvent composition on the solvation of the ions is discussed. A preferential hydration of Na+, Cl- and I- ions in water-methanol mixtures has been found.

Self-diffusion in molten sodium chloride: a test of the applicability of the Nernst—Einstein equation

1957 ◽  
Vol 241 (1227) ◽  
pp. 554-567 ◽  
Keyword(s):  
Sodium Chloride ◽  
Einstein Equation ◽  
Diffusion Coefficients ◽  
Liquid Sodium ◽  
Einstein Relation ◽  
Transport Numbers ◽  
Self Diffusion ◽  
Capillary Method ◽  
Molten Sodium ◽  
The Individual

Self-diffusion coefficients of sodium and chlorine in molten sodium chloride have been determined by the capillary method with the aid of 22 Na and 36 Cl radio-tracers. The results can be represented by the expressions D Na = 8x 10 -4 exp (-4000/RT) and D Cl = 33 x 10 -4 exp (-8500/.RT). These values, when inserted in the Nernst-Einstein equation (A = (F 2 /RT) (D+ D-)), lead to a value of the equivalent conductance, A, which is about 40 % greater than that observed experimentally. The evidence that the diffusion coefficients of Na + and Cl - are similar in magnitude and that the activation energies are much smaller than the heat of vaporization of liquid sodium chloride, support the conclusions, derived from other evidence, that the free volume in the molten salt consists largely of holes, analogous to vacant lattice sites. On the basis of this model, the discrepancy in the Nernst-Einstein relation can readily be interpreted in terms of two diffusion mechanisms, one being normal vacancy diffusion of single ions, and the other a process in which no net charge is displaced in a unit step. It is suggested that the latter is the Seitz-Dienes mechanism of consecutive jumps of cation and anion in coupled vacancies. The interpretation mentioned enables the individual mobilities of Na + and Cl - ions to be determined, and hence their transport numbers can be calculated (t Na += 0.71, t Cl - = 0.29 at 935° C). The individual diffusion coefficients of the ions and of the coupled vacancies are in reasonable agreement with the Stokes-Einstein equation.

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