Streaming potential method for characterizing the overlapping of diffuse layers of the electrical double layers between oppositely charged particles

2015 ◽  
Vol 478 ◽  
pp. 22-29 ◽  
Author(s):  
Zhong-yi Li ◽  
Jiu-yu Li ◽  
Ren-kou Xu ◽  
Zhi-neng Hong ◽  
Zhao-dong Liu
Keyword(s):  
Charged Particles ◽  
Streaming Potential ◽  
Potential Method ◽  
Double Layers ◽  
Electrical Double Layers ◽  
Diffuse Layers ◽  
Oppositely Charged

Effect of Fe/Al oxides on desorption of Cd2+ from soils and minerals as related to diffuse layer overlapping

Soil Research ◽  
2011 ◽  
Vol 49 (3) ◽  
pp. 231 ◽  
Author(s):  
Yan-ping Wang ◽  
Ren-kou Xu ◽  
Jiu-yu Li
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Charged Particles ◽  
Double Layers ◽  
Mineral Particles ◽  
Variable Charge ◽  
Electrical Double Layers ◽  
Oppositely Charged ◽  
Positively Charged

Cadmium is a toxic metal with high reactivity in acid variable charge soils. Adsorption and desorption of Cd2+ in soil and mineral particles can be affected by the interaction between the electrical double layers on oppositely charged particles, because the interaction can decrease the surface-charge density of the particles. We studied the effect of Fe/Al oxides on desorption of Cd2+ from soils and minerals and proposed the desorption mechanisms based on the overlapping of diffuse layers between negatively charged soils and mineral particles and positively charged Fe/Al oxide particles. Our results indicate that the overlapping of diffuse layers of electrical double layers between positively charged Fe/Al oxides [crystalline and amorphous Al(OH)3 and amorphous Fe(OH)3] and negatively charged Ultisol, Alfisol, kaolinite, and bentonite caused the effective negative surface-charge density on the soils and minerals to become less negative, and thus the adsorption affinity of these negatively charged surfaces for Cd2+ declined as a result of the incorporation of the Fe/Al oxides. Consequently, the release of exchangeable Cd2+ from the surfaces of the soils and minerals increased with the amount of Fe/Al oxides added. The more positive the charge on the surfaces of the Fe/Al oxides, the stronger the interaction of the electrical double layers between the oxides and soils and minerals, and thus the greater the release of Cd2+ from the soils and minerals. A decrease in pH led to an increase in the positive surface charge on the Fe/Al oxides and enhancement of the interaction of the electrical double layers between the oxides and soils and minerals. As a result, more Cd2+ was desorbed from the soils and minerals. This study suggests that the interaction between oppositely charged particles of variable charge soils can enhance the mobility of cadmium in the soils and thus increase its environmental risk.

scholarly journals ON THE CAUSE OF THE INFLUENCE OF IONS ON THE RATE OF DIFFUSION OF WATER THROUGH COLLODION MEMBRANES. II

1920 ◽  
Vol 2 (5) ◽  
pp. 563-576 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Opposite Sign ◽  
Pure Water ◽  
Critical Value ◽  
Relative Influence ◽  
Double Layers ◽  
Electrical Double Layers ◽  
Charged Ions ◽  
Oppositely Charged ◽  
Charged Water

1. It had been shown in previous publications that when pure water is separated from a solution of an electrolyte by a collodion membrane the ion with the same sign of charge as the membrane increases and the ion with the opposite sign of charge as the membrane diminishes the rate of diffusion of water into the solution; but that the relative influence of the oppositely charged ions upon the rate of diffusion of water through the membrane is not the same for different concentrations. Beginning with the lowest concentrations of electrolytes the attractive influence of that ion which has the same sign of charge as the collodion membrane upon the oppositely charged water increases more rapidly with increasing concentration of the electrolyte than the repelling effect of the ion possessing the opposite sign of charge as the membrane. When the concentration exceeds a certain critical value the repelling influence of the latter ion upon the water increases more rapidly with a further increase in the concentration of the electrolyte than the attractive influence of the ion having the same sign of charge as the membrane. 2. It is shown in this paper that the influence of the concentration of electrolytes on the rate of transport of water through collodion membranes in electrical endosmose is similar to that in the case of free osmosis. 3. On the basis of the Helmholtz theory of electrical double layers this seems to indicate that the influence of an electrolyte on the rate of diffusion of water through a collodion membrane in the case of free osmosis is due to the fact that the ion possessing the same sign of charge as the membrane increases the density of charge of the latter while the ion with the opposite sign diminishes the density of charge of the membrane. The relative influence of the oppositely charged ions on the density of charge of the membrane is not the same in all concentrations. The influence of the ion with the same sign of charge increases in the lowest concentrations more rapidly with increasing concentration than the influence of the ion with the opposite sign of charge, while for somewhat higher concentrations the reverse is true.

Wave motion of low-tension interfaces with electrical double layers

1972 ◽  
Vol 55 (4) ◽  
pp. 641-657 ◽  
Author(s):  
C. A. Miller
Keyword(s):  
Approximate Solution ◽  
Ion Transport ◽  
Wave Motion ◽  
Liquid Films ◽  
Double Layers ◽  
Potential Approximation ◽  
Electrical Double Layers ◽  
Interfacial Motion ◽  
Diffuse Layers ◽  
Low Tension

An approximate solution is developed for the system of equations describing flow and ion transport in a diffuse electrical double layer slightly perturbed from equilibrium. The approximation is valid only when the potential difference across the diffuse layer is small, less than about 25 mV. When the approximate solution is used to study wave motion of low-tension interfaces, it is found chat ion transport in diffuse layers slows down interfacial motion in both stable and unstable situations. Although the slowing effect is relatively small (a few per cent or less) when the small potential approximation applies, the form of the solution suggests that the effect could be significant for potential differences in the 50–100 mV range, which exist in many systems of interest. There are also indications that the slowing effect can significantly influence wave motion of thin liquid films with diffuse layers, e.g. soap films, although a detailed analysis of the thin-film situation is not carried out.

Electrokinetics of polymeric fluids in narrow rectangular confinements

Soft Matter ◽  
2021 ◽  
Author(s):  
Aditya Natu ◽  
Uddipta Ghosh
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Double Layers ◽  
Polymeric Fluids ◽  
Polymeric Liquids ◽  
Electrical Double Layers

Flow of polymeric liquids in narrow confinements of rectangular cross section, in the presence of electrical double layers is analyzed here. Our analysis is motivated by the fact that many...

Molecular solvent models of electrical double layers

1991 ◽  
Vol 36 (11-12) ◽  
pp. 1677-1684 ◽  
Author(s):  
G.M. Torrie ◽  
G.N. Patey
Keyword(s):  
Double Layers ◽  
Electrical Double Layers ◽  
Solvent Models

The Determination of Electrokinetic Coupling-Coefficient and Zeta Potential of Rock Samples by Electrokinetic Measurements

2012 ◽  
Vol 516-517 ◽  
pp. 1870-1873 ◽  
Author(s):  
Jun Wang ◽  
Heng Shan Hu
Keyword(s):  
Zeta Potential ◽  
Coupling Coefficient ◽  
Streaming Potential ◽  
Potential Method ◽  
Surface Conductivity ◽  
Reliable Estimate ◽  
Surface Conductance ◽  
Streaming Current ◽  
Low Concentrations

The electrokinetic effects are important in the understanding of electric properties in porous medium. In this study, the streaming potential and streaming current of saturated samples are measured at different concentrations, then three methods are applied to obtain the zeta-potential and electrokinetic coupling coefficient. The study shows that the results obtained from streaming potential and streaming current methods agree well with each other, but the results obtained from simplified streaming potential method become seriously inaccurate at low concentrations due to the influence of surface conductance. This experimental study also provides a reliable estimate of the surface conductivity and its contribution to zeta-potential at given concentrations.

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