Approximate Analytic Expression for the Electrophoretic Mobility of a Spherical Colloidal Particle

✍ Scribed by Hiroyuki Ohshima

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 83 KB
• Volume: 239
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.2001.7608

✦ Synopsis

An approximate analytic expression for the electrophoretic mobility of a spherical colloidal particle in a symmetrical electrolyte solution is obtained. This mobility expression, which is correct to the order of the third power of the ζ-potential of the particle, considerably improves Henry's mobility formula (Proc. R. Soc. London Ser. A 133, 106 (1931)) and has a much simpler form than similar mobility formulas expressed in powers of ζ derived by Overbeek (Kolloid-Beihefte 54, 287 (1943)) and by Booth (Proc. R. Soc. London Ser. A 203, 514 (1950)). Comparison with the exact computer calculation by O'Brien and White (J. Chem. Soc. Faraday Trans. 2 74, 1607 (1978)) shows that the obtained mobility formula is an excellent approximation, especially for small κa (where κ is the Debye-H ückel parameter and a is the particle radius) in which region no other simple analytic mobility formulas are available than Henry's formula, which is correct to order ζ and is applicable only for low ζ.