scholarly journals Influence of the Ionic Composition of Fluid Medium on Red Cell Aggregation

1973 ◽  
Vol 61 (5) ◽  
pp. 655-668 ◽  
Author(s):  
Kung-Ming Jan ◽  
Shu Chien
Keyword(s):  
Ionic Strength ◽  
Surface Charge ◽  
Double Layer ◽  
Surface Potential ◽  
Electric Double Layer ◽  
Divalent Cations ◽  
Ionic Composition ◽  
Cell Aggregation ◽  
Fluid Medium ◽  
Induced Aggregation

The effects of ionic strength and cationic valency of the fluid medium on the surface potential and dextran-induced aggregation of red blood cells (RBC's) were investigated. The zeta potential was calculated from cell mobility in a microelectrophoresis apparatus; the degree of aggregation of normal and neuraminidase-treated RBC's in dextrans (Dx 40 and Dx 80) was quantified by microscopic observation, measurement of erythrocyte sedimentation rate, and determination of low-shear viscosity. A decrease in ionic strength caused a reduction in aggregation of normal RBC's in dextrans, but had no effect on the aggregation of neuraminidase-treated RBC's. These findings reflect an increase in electrostatic repulsive force between normal RBC's by the reduction in ionic strength due to (a) a decrease in the screening of surface charge by counter-ions and (b) an increase in the thickness of the electric double layer. Divalent cations (Ca++, Mg++, and Ba++) increased aggregation of normal RBC's in dextrans, but had no effect on the aggregation of neuraminidase-treated RBC's. These effects of the divalent cations are attributable to a decrease in surface potential of normal RBC's and a shrinkage of the electric double layer. It is concluded that the surface charge of RBC's plays a significant role in cell-to-cell interactions.

Demonstration of the enhancement of gate bias and ionic strength in electric-double-layer field-effect-transistor biosensors

2021 ◽  
Vol 334 ◽  
pp. 129567
Author(s):  
Chang-Run Wu ◽  
Shin-Li Wang ◽  
Po-Hsuan Chen ◽  
Yu-Lin Wang ◽  
Yu-Rong Wang ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Double Layer ◽  
Electric Double Layer ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Gate Bias ◽  
Effect Transistor

scholarly journals Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

SPE Journal ◽  
2017 ◽  
Vol 23 (01) ◽  
pp. 84-101 ◽  
Author(s):  
Maxim P. Yutkin ◽  
Himanshu Mishra ◽  
Tadeusz W. Patzek ◽  
John Lee ◽  
Clayton J. Radke
Keyword(s):  
Ionic Strength ◽  
Ion Exchange ◽  
Crude Oil ◽  
Surface Charge ◽  
Double Layer ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Diffuse Double Layer ◽  
Low Salinity ◽  
Low Salinity Waterflooding

Summary Low-salinity waterflooding (LSW) is ineffective when reservoir rock is strongly water-wet or when crude oil is not asphaltenic. Success of LSW relies heavily on the ability of injected brine to alter surface chemistry of reservoir crude-oil brine/rock (COBR) interfaces. Implementation of LSW in carbonate reservoirs is especially challenging because of high reservoir-brine salinity and, more importantly, because of high reactivity of the rock minerals. Both features complicate understanding of the COBR surface chemistries pertinent to successful LSW. Here, we tackle the complex physicochemical processes in chemically active carbonates flooded with diluted brine that is saturated with atmospheric carbon dioxide (CO2) and possibly supplemented with additional ionic species, such as sulfates or phosphates. When waterflooding carbonate reservoirs, rock equilibrates with the injected brine over short distances. Injected-brine ion speciation is shifted substantially in the presence of reactive carbonate rock. Our new calculations demonstrate that rock-equilibrated aqueous pH is slightly alkaline quite independent of injected-brine pH. We establish, for the first time, that CO2 content of a carbonate reservoir, originating from CO2-rich crude oil and gas, plays a dominant role in setting aqueous pH and rock-surface speciation. A simple ion-complexing model predicts the calcite-surface charge as a function of composition of reservoir brine. The surface charge of calcite may be positive or negative, depending on speciation of reservoir brine in contact with the calcite. There is no single point of zero charge; all dissolved aqueous species are charge determining. Rock-equilibrated aqueous composition controls the calcite-surface ion-exchange behavior, not the injected-brine composition. At high ionic strength, the electrical double layer collapses and is no longer diffuse. All surface charges are located directly in the inner and outer Helmholtz planes. Our evaluation of calcite bulk and surface equilibria draws several important inferences about the proposed LSW oil-recovery mechanisms. Diffuse double-layer expansion (DLE) is impossible for brine ionic strength greater than 0.1 molar. Because of rapid rock/brine equilibration, the dissolution mechanism for releasing adhered oil is eliminated. Also, fines mobilization and concomitant oil release cannot occur because there are few loose fines and clays in a majority of carbonates. LSW cannot be a low-interfacial-tension alkaline flood because carbonate dissolution exhausts all injected base near the wellbore and lowers pH to that set by the rock and by formation CO2. In spite of diffuse double-layer collapse in carbonate reservoirs, surface ion-exchange oil release remains feasible, but unproved.

Electrokinetics at High Ionic Strength and Hypothesis of the Double Layer with Zero Surface Charge†

Langmuir ◽  
2005 ◽  
Vol 21 (22) ◽  
pp. 9990-9997 ◽  
Author(s):  
A. Dukhin ◽  
S. Dukhin ◽  
P. Goetz
Keyword(s):  
Ionic Strength ◽  
Surface Charge ◽  
Double Layer ◽  
High Ionic Strength

Influence of electrode polarization on the capacitance of an electric double layer at and around zero surface charge

2011 ◽  
Vol 109 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Christopher W. Outhwaite ◽  
Stanislaw Lamperski ◽  
Lutful Bari Bhuiyan
Keyword(s):  
Surface Charge ◽  
Double Layer ◽  
Electric Double Layer ◽  
Electrode Polarization

A 2D Electric Double Layer Model for Biological Nanochannels

2006 ◽  
Author(s):  
Fuzhi Lu ◽  
Daniel Y. Kwok
Keyword(s):  
Double Layer ◽  
Surface Potential ◽  
Electric Double Layer ◽  
Classical Model ◽  
Time Dependent ◽  
Layer Model ◽  
End Effects ◽  
Double Layer Model ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation

We developed a 2D electric double layer model for biological nanochannels based on the linearlized Poisson-Boltzmann equation with arbitrary surface potential. Time dependent adsorption kinetics was used in the model to examine the variation of electric double layer distribution and compare with that from the classical model. Based on the 2D model, EDL interaction for heavily patched arbitray surface potential was found to be much weaker in such biological nanochannels. Channel end effects are also found to be significant and not negligible.

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