2.4. Adsorption experiments
The studies of MO adsorption were performed by batch adsorption
method. For sorption kinetics, a series of 250 mL flask containing
0.1 g of adsorbent and 50 mL of MO solution at concentration
500 mg L1 was prepared. The mixtures were continuously shaken
at 30 C and 250 rpm. Samples were taken at different time intervals
and filtered using 0.2 lm Millipore membrane filters and the
filtrates were analyzed for MO concentration. The adsorption
capacity (qt, mg g1) at any time, t was calculated using the following
equation:
qt ¼ ðCo CtÞV=m ð1Þ
where Co (mg L1) is the initial concentration of the solute in
aqueous solution, Ct (mg L1) is the solute concentration in aqueous
phase at time t, V (L) is the solution volume and m (g) is the
mass of the adsorbent. For experiments studying the effect of pH
on adsorption, 50 mL of MO solution with initial concentration
of 500 mg L1 was used. The pH was adjusted by addition of
0.1 M HCl or NaOH solution and the contact time was set at 5 h.