scholarly journals Theoretical Modelling of Ion Exchange Processes in Glass: Advances and Challenges

2021 ◽  
Vol 11 (11) ◽  
pp. 5070
Author(s):  
Xesús Prieto-Blanco ◽  
Carlos Montero-Orille
Keyword(s):  
Ion Exchange ◽  
Diffusion Coefficients ◽  
Molten Salts ◽  
Theoretical Modelling ◽  
Copper Films ◽  
Theoretical Frameworks ◽  
Self Diffusion ◽  
Exchange Processes ◽  
The One ◽  
Made In

In the last few years, some advances have been made in the theoretical modelling of ion exchange processes in glass. On the one hand, the equations that describe the evolution of the cation concentration were rewritten in a more rigorous manner. This was made into two theoretical frameworks. In the first one, the self-diffusion coefficients were assumed to be constant, whereas, in the second one, a more realistic cation behaviour was considered by taking into account the so-called mixed ion effect. Along with these equations, the boundary conditions for the usual ion exchange processes from molten salts, silver and copper films and metallic cathodes were accordingly established. On the other hand, the modelling of some ion exchange processes that have attracted a great deal of attention in recent years, including glass poling, electro-diffusion of multivalent metals and the formation/dissolution of silver nanoparticles, has been addressed. In such processes, the usual approximations that are made in ion exchange modelling are not always valid. An overview of the progress made and the remaining challenges in the modelling of these unique processes is provided at the end of this review.

scholarly journals Negative Pressure Regimes in Ionic Liquids: Structure and Interactions in Stretched Liquids as Probed by NMR

2018 ◽  
Author(s):  
Luis Paulo Rebelo
Keyword(s):  
Ionic Liquids ◽  
Negative Pressure ◽  
Diffusion Coefficients ◽  
Sharp Increase ◽  
Molten Salts ◽  
Structure And Properties ◽  
Saturated Liquid ◽  
Nmr Studies ◽  
Preliminary Testing ◽  
Self Diffusion

In this work, a broad pallete of macroscopically sized samples of ionic liquids was used, in which tensions of about -100 MPa were obtained in preliminary testing methodologies before cavitation would occur. Preliminary NMR studies have been performed on ionic liquids under homogeneous tension. Upon entering into these metastable regimes of negative pressure, it is possible to observe a sharp increase in the anion and cation self-diffusion coefficients as compared to the equilibrium saturated liquid conditions at identical temperatures. [L02 - Molten Salts and Ionic Liquids 21, Structure and Properties I, Tuesday, October 2nd, 10:40, #1832-AiMES2018, Universal 9 – Abstract Oral #116064 ]

scholarly journals Notizen: On the Validity of Inter- and Self-Diffusion Measurements in Molten Salts by Methods Applying Multiporous Fritted Discs

1965 ◽  
Vol 20 (4) ◽  
pp. 632-633
Author(s):  
Carl-Axel Sjöblom ◽  
Arnold Lundén
Keyword(s):  
Binary Mixtures ◽  
Diffusion Coefficients ◽  
Molten Salts ◽  
Gravimetric Method ◽  
Cation Diffusion ◽  
Self Diffusion ◽  
Sources Of Error

A gravimetric method has been used to study interdiffusion in binary mixtures of AgNO3 and KNO3 over the range 50 -75 mole % AgNO3 at tem peratures below 200°C. The obtained cation diffusion coefficients are of the order of 2 × 10-6 cm2 sec-1 i.e. considerably lower than what might have been expected from other diffusion m easurements. It has previously been found that there is a tendency for self-diffusion coefficients obtained with fritted discs to be lower than those obtained with the conventional open-end capillary technique. Some possible sources of error are discussed.

Simulation of the Structure and Properties of Room Temperature Molten Salts 1-Ethyl-3-Methyl-Imidazolium Chloride/Chloroaluminate

2012 ◽  
Vol 430-432 ◽  
pp. 547-550 ◽  
Author(s):  
Guo Cai Tian ◽  
Ding Wang ◽  
Ya Dong Li
Keyword(s):  
Diffusion Coefficients ◽  
Molten Salts ◽  
Room Temperature ◽  
Molar Fraction ◽  
Chemical Properties ◽  
Simulation Method ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Imidazolium Chloride ◽  
Self Diffusion

Molecular dynamics simulation method is used to study the [Emim]Cl ionic liquid at the 300K. The density is obtained as 1.1744g/cm3 which agree well with the experimental value (1.186g/cm3) and the relative deviation is only 0.9%. The microstructure, dynamics, and physical chemical properties such as radial distribution functions, diffusion coefficients, viscosity, conductivity of room temperature molten salts [Emim]Cl/AlCl3 with different molar fraction of AlCl3 are calculated. It is shown that the density and electrical conductivity increase, whereas the viscosity decreases with the increasing of molar fraction of AlCl3. The self-diffusion coefficients of [Emim]+, Cl- and AlCl3 increases and the changes of self-diffusion coefficient of AlCl3 is the biggest as to molar fraction increase.

An Incomplete-Dissociation Model for Diffusion and Ionic Conduction in Pure Molten Salts

1983 ◽  
Vol 38 (5) ◽  
pp. 516-519 ◽  
Author(s):  
A. Klemm
Keyword(s):  
Diffusion Coefficients ◽  
Molten Salts ◽  
Ionic Conduction ◽  
Diatomic Molecules ◽  
The Self ◽  
Degree Of Dissociation ◽  
Self Diffusion ◽  
Internal Mobility ◽  
Dissociation Model ◽  
D Values

Diffusion and ionic conduction in pure 1:1 molten salts is described by an incomplete-disso­ciation model comprising neutral diatomic molecules and monoatomic ions. The internal mobility b+- and the self-diffusion coefficients D+ and D- are given in terms of the six inter­particle friction coefficients and the degree of dissociation. By an approximation it is possible to derive from experimental D+ and D- values an apparent degree of dissociation which ranges from 0.93 for NaCl to 0.51 for TlCl and decreases with temperature.

Self-diffusion Measurements in Molten Salts

1962 ◽  
Vol 17 (3) ◽  
pp. 191-195
Author(s):  
Lars-Erik Wallin
Keyword(s):  
Poiseuille Flow ◽  
Diffusion Coefficients ◽  
Molten Salts ◽  
Concentration Distribution ◽  
New Technique ◽  
Self Diffusion ◽  
A New Technique

A new technique has been developed for the determination of self-diffusion coefficients in molten salts. Two chemically identical columns of salt, one of which is radioactive, are allowed to diffuse into each other in a capillary. The diffusion is interrupted by means of freezing from the bottom. Equations are derived for the calculation of the disturbed concentration distribution, assuming that the contraction on freezing causes a Poiseuille flow in the melt above.

scholarly journals A NMR Spin-Echo Study of Diffusion in Molten Salts

2004 ◽  
Vol 59 (1-2) ◽  
pp. 51-58 ◽  
Author(s):  
Günter Palmer ◽  
Joachim Richter ◽  
Manfred D. Zeidler
Keyword(s):  
High Pressure ◽  
Titanium Alloy ◽  
Diffusion Coefficients ◽  
High Frequency ◽  
Molten Salts ◽  
Pressure Range ◽  
Spin Echo ◽  
Ambient Pressure ◽  
Pressure Probe ◽  
Self Diffusion

Pressure-dependent measurements of the cationic self-diffusion coefficients of molten (Na, Li)NO3 were carried out at 613 K. The pressure range lies between ambient pressure and 200 MPa. A new high-pressure probe, operating with heating coils, was constructed from titanium alloy. The temperature difference across the probe could be confined to 2.5 K. By use of a switchable high-frequency coil the nuclei lithium and sodium could be measured in succession within the same sample. The activation volumes are composition-dependent and range from 5 to 9 cm3mol−1.

scholarly journals Electrical Conductivity of Solid and Molten Lithium Sulfate

1965 ◽  
Vol 20 (2) ◽  
pp. 235-238 ◽  
Author(s):  
Arnold Kvist ◽  
Arnold Lundén
Keyword(s):  
Electrical Conductivity ◽  
Molten Salts ◽  
Einstein Relation ◽  
Lithium Sulfate ◽  
Self Diffusion ◽  
Ionic Melts ◽  
Empirical Relations ◽  
Molten Lithium ◽  
Self Diffusion Coefficient ◽  
Made In

The electrical conductivity of lithium sulfate has been measured over the temperature range 575—970°C. It is found that ARRHENIUS equations fit the experimental data slightly less well than empirical relations, such asϰ= (-3.297+6.894 · 10-3 t +0.527 · 10-6t2) Ω-1 cm-1 for cubic Li2SO4 and ϰ= (-13.639+35.204 · 10-3 t-17.251 · 10-6t2) Ω-1 cm-1 for molten Li2SO4(t in degr. C).Due to the similarity in transport properties between cubic Li2SO4 and molten salts, comparisons with ionic melts are made in the discussion of our results. The ratio between the conductivity and the cation self-diffusion coefficient is less than required by the NERNST-EINSTEIN relation, which indicates that rotation or ring mechanisms are of importance for diffusion in cubic Li2SO4.

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