The influence of initial solution pH on Cr(VI) removal was
studied over a pH range of 2–3.5. The pH values of the Cr(VI)
solutions were adjusted by adding negligible volume of 0.1 M
NaOH or 0.1 M HCl solutions. The effect of adsorbent dosage on Cr
(VI) removal was studied by agitating different mass (0.5–2.5 g/L)
of adsorbent in 20 mL solution with an initial Cr(VI) concentration
of 105 mg/L.
For the adsorption kinetic studies, 50 mg of the activated carbon
was dispersed in 50 mL of Cr(VI) (105 mg/L, pH 2.7) aqueous
solution and agitated. At certain time intervals, 5 mL of the solution
mixture was extracted and subjected to
filtration and chromium
concentration analysis. The adsorption amounts were calculated
following Eq