The name is absent

Chapter 4

4.3. Wettability of kaolinite characterized by zeta potential

4.3.1. Introduction

Effect of NaOH and Na2SiO3 has been discussed in section 4.2.3. In this case,
wettability of kaolinite depends on the surface charge change. Zeta potential can
be used to characterize oxide surface charge ^[11]’^[12], which is related to wettability.
Zeta potential of clay solids can also directly characterize the wettability change of
clay solids. Liu et al. used zeta potential measurement to study the wettability of
clay solids and the interactions between bitumen and clay ^{[13L [14]}. Wettability
change may be important to the stability of water-in-bitumen emulsions.

To characterize the wettability change of kaolinite, zeta potentials of kaolinite
in synthetic brine with different additives were measured. Sodium hydroxide
(NaOH), sodium citrate (NasCeH₅O₇), sodium meta-silicate (Na2SiO3), sodium
ortho-silicate (Na4SiO4), and sodium carbonate (Na2CO3) were used to change
surface charge and zeta potentials of kaolinite. In order to analyze and correlate
the experimental zeta potential of kaolinite in synthetic brine, simplified Gouy-
Stern-Grahame model was used ^[15].

4.3.2. Zeta potential model

In Gouy-Stern-Grahame model, the double layer can be divided into two
regions: 1 ) the compact or Stern layer very near the solid surface in which the

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