Electromobility of Mica Particles Dispersed in Aqueous Solutions

R. M. Pashley1
Department of Chemical Engineering, Princeton University Princeton, New Jersey 08544
1 On leave from Department of Applied Mathematics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601, Australia.

Abstract: Mobility measurements were made for dry-ground mica particles dispersed in aqueous KCl, Cr(NO3)3, and cetyltrimethylammonium bromide (CTAB) solutions. In the latter solutions charge reversal occurred at about 2 × 10−6 M and 3 × 10−5 M, respectively. Negative zeta potentials in KCl solutions calculated using the Smoluchowski equation are about one third of the corresponding values obtained from streaming potentials and force measurements using mica sheets. Good agreement, however, was obtained when positively charged groups created during grinding were neutralized, and the zeta potentials were corrected according to the procedure of O'Brien and White with an assumed average particle size of 0.25 µm. When the zeta potentials of positively charged particles were corrected in this way, agreement with values calculated from force measurements was also improved.

Key Words: Electromobility • Force measurements • Mica • Smoluchowski equation • Streaming potential

Clays and Clay Minerals; June 1985 v. 33; no. 3; p. 193-199; DOI: 10.1346/CCMN.1985.0330304
© 1985, The Clay Minerals Society
Clay Minerals Society (www.clays.org)