An Approximate Analytic Expression for the Surface Charge Density/Surface Potential Relationship for a Spherical Colloidal Particle

✍ Scribed by Shiqi Zhou

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 93 KB
• Volume: 208
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1998.5746

✦ Synopsis

An approximate analytic expression for the surface charge density/surface potential relationship (/ 0 ) for a spherical colloidal particle in a solution of mixed and nonsymmetrical electrolytes is obtained by solving a nonlinear Poisson-Boltzmann equation using a linearization approximation. The approximate analytic expression is fit for the case of large a( ‫؍‬ Debye-Hu ¨ckel inverse parameter, a ‫؍‬ colloidal particle radius), but for the case of small a, the approximate analytic expression is applicable only when a > 0.03, with a maximal percent relative error of 5.0, even for surface potentials up to 334 mV (25°C). The approximate analytic expressions reported in the literature have a low limit of a, 0.5 or even 2.0. The present approximate analytic expression has a simple structure and is characterized by the ease with which it is adapted for analysis.