The Langmuir and Freundlich coefficients for single solute
adsorption isotherms and their corresponding correlation coef-
ficients are presented in Table 3. The results showed a good fit of
the Freundlich model to the experimental data compared to the
Langmuir model. This observation is not rare as similar findings
have been previously reported [41,43,44]. This indicates that
sorption of the oils onto human hair occurred on heterogeneous
sites with non-uniform distribution of energy level rather than on
a homogeneous site with uniform distribution of energy. The value
of constant n, which indicates the intensity of adsorption, showed a
favourable sorption of oil onto human hair