The results gained on adsorption test are plotted in Fig. 11.When
the results are investigated, it can be concluded that adsorption
on activated carbon presents a low performance for dye removal
at the higher pH (pH = 7). The dye removal based on just adsorption
increased when the pH is decreased from pH= 7 to pH= 3. The
adsorption effect of activated carbon increased in the acidic conditions
and also at a higher temperature. Orfão et al., reported that,
adsorption performance is highly affected by the pH of the solution,
since it influences the surface charge of the activated carbons and
consequently the intensity of the electrostatic interactions between
dye molecules and the adsorbents surface [18]. It can be concluded
that at higher temperatures the adsorption effect of activated carbon
and the effect of oxidation on the removal were compatible