Table I.

Measured and computed electrical potentials in some solutions

Values for ψWall, measured were taken from the fitted curves in Figures 7 and 9 and from a curve fitted to the pooled data from Figure 8, A through C. Concentrations are in millimolar and potentials in millivolts.

LaCl3 pH CaCl2 NaCl ψWall, measured ψWall, computeda ψPM, computedb
0.001 5.6 0 0.1 −78.9 −72.0 −44.6
0.01 5.6 0 0.1 −55.7 −54.2 −25.4
0.1 5.6 0 0.1 −32.5 −35.5 −6.0
1 5.6 0 0.1 −9.3 −16.9 12.7
0 5.00 0 0.1 −87.4 −94.7 −71.0
0 4.00 0 0.1 −54.0 −59.1 −16.5
0 3.00 0 0.1 −9.4 −13.1 34.6
0 5.6 0.01 0.1 −88.6 −81.2 −85.1
0 5.6 0.1 0.1 −60.1 −56.6 −62.8
0 5.6 1 0.1 −31.6 −29.5 −36.1
0 5.6 0 0.1 −98.6 −110.6 −101.3
0 5.6 0 1 −57.5 −70.2 −85.5
0 5.6 0 10 −16.4 −22.5 −59.0
  • a Parameter values for the Donnan-plus-binding model: RTotal = 0.0211 m and KR,H = 9450.

  • b ψPM, computed was computed by a Gouy-Chapman-Stern model (Kinraide et al., 1998) in which negative-site binding constants are KR,Na = I, KR,Ca = 30, KR,La = 2,200, KR,H = 21,500 m−1.