The present results showed that, the
metal removal percentage was increased up to pH 5.5 and then
decreased. In contrast, when the pH was increased, a partial
desorption of protons occurs allowing the sorption of Cd(II)
onto the sites left by protons at the surface of biomass and
the biosorption reached the maximum (91.9%) around pH
5.5. According to this, it may be suggested that there was a
clear competition for the biomass sorption sites between Cd(II)
and proton.The decrease in biosorption at higher pH values
(pH > 5.5) may be attributed to that the amount of OH- ions