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Electrokinetic Phenomena in concentrated disperse systems: general problem formulation and Spherical Cell Approach
Emilij K Zholkovskij1, Jacob H Masliyah, Vladimir N Shilov
1Institute of Bio-Colloid Chemistry of Ukrainian Academy of Sciences, Vernadskogo,42, 03142, Kiev, Ukraine.
Advances in Colloid and Interface Science
|June 30, 2007
Summary
This study revisits the Spherical Cell Approach for electrokinetic phenomena in concentrated systems. It resolves contradictions by defining correct boundary conditions, leading to a new method for predicting kinetic coefficients.
Area of Science:
- Physical Chemistry
- Colloid and Surface Science
- Electrochemistry
Background:
- Electrokinetic phenomena in concentrated disperse and colloid systems are crucial for understanding material behavior.
- The Spherical Cell Approach has been widely used but suffers from contradictions due to boundary condition issues.
- Existing models often yield conflicting results, necessitating a re-evaluation of the theoretical framework.
Purpose of the Study:
- To critically review advances in the Spherical Cell Approach for electrokinetic phenomena.
- To identify and resolve contradictions arising from boundary condition implementations.
- To develop a rigorous and accurate method for predicting kinetic coefficients in concentrated suspensions.
Main Methods:
- Revisiting the theory of electrokinetic phenomena with a focus on outer boundary conditions of the Spherical Cell.
- Formulating a general mathematical problem for disperse systems under pressure, gravity, and electric fields.
- Deriving a complete set of boundary conditions based on volume averaging equivalence.
- Employing a small perturbation parameter method with normalized zeta potential.
Main Results:
- Strict definitions for kinetic coefficients were established.
- General relationships, including Smoluchowski expressions and Onsager relations, were rederived.
- A novel method for predicting kinetic coefficients was developed, accounting for zeta potential terms.
- Predictions from the new method were compared against existing literature, highlighting model validity.
Conclusions:
- The study provides a corrected version of the Spherical Cell Approach by addressing boundary condition inconsistencies.
- The developed method offers a more accurate prediction of kinetic coefficients in concentrated electrokinetic systems.
- This work clarifies the validity of various models in the literature concerning electrokinetic phenomena.
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