The adsorption isotherms for the cationic surfactant, CPC on the kaolin particles as a function of
equilibrium concentration are shown in Figure 3. The isotherms reach an apparent plateau adsorbed
amount at a concentration that corresponds roughly to the surfactant cmc, this result corresponds well to
that of our previous work [4]. In comparison, McCarron et al., [15] found an apparent adsorption plateau
at about 5.8 moles/m2
for CPC on kaolin at pH between 3 to 5. The linear plots of Langmuir isotherm
of CPC adsorption on kaolin are shown in Figure 4. The maximum adsorption of CPC decreases when
PVA has been pre-adsorbed(PVA+CPC mode), namely 6.5 moles/m2
for CPC alone and 5.9 moles/m2
for CPC with pre-adsorbed PVA (Tab