Chapter 4
[SiO]⅝(H*)exp(-⅛
[SiOH] =-------------⅛-
[4.23]
ʌ^sɪ-
[АЮ’] =
[4.24]
[¾(H*)exp(-⅛J2
[A1OH^] =
a, (H÷ )exp(- ≤)+—J— [¾ (H * )exp(⅛]2
^A1+-^A1-
[4.25]
[SiO- ] =----------------ʒ-ɪ;--------------r- [4.26]
1 + W-¾ + τr∏^[^ (H+)exp(-⅛]2
ʌsi- ʌ'ɪ ʌsi+^-
[SiOHj] =
Wsi
½
[⅝(H*)exp(-⅛]2
[¾(H∙)exp(-⅛2
[4.27]
Here K(Ka∣i, Ka∣2. Ksm and Ksi2) /V (Wai. Afa and Λ∕b) are equilibrium constants
and surface sites densities, respectively, which can be obtained by fitting with the
experiment data. From Eqs. [4.19] - [4.27], zeta potential ζca∣ can be calculated
from the initial evaluates of K and /V. Parameters estimation was done using
Matlab optimization toolbox. The object function to be determined is ∣∣ <ca∣ - ζe×p Il-
Iteration terminates when ∣∣ ζca∣ - ζe×p ∣∣< tolerance.
Figure 4.18 shows the experiment data and fitted curve of kaolinite zeta
potentials in 0.05 M NaCI brine at different pH. Zeta potential of kaolinite becomes
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