The adsorption experiments were carried out by batch process, 1.00 g of biosorbent was placed in
Erlenmeyer flasks with 100 mL solution of methylene blue of desired concentration. The mixture was
agitated at 100 rpm at 30, 45 and 60°C. The contact time was varied from 0 to 220 minutes. At
predetermined time, the flasks were withdrawn from the agitator and the reaction mixtures were filtered
through Whatman filter paper No. 40. For thermodynamic study, the experiment was performed using 1g
DPL powder added to 100 mL of methylene blue solution in 250 mL flasks. The agitation was at 100 rpm
for 160 min at pH=6.5 . All the experiments were performed in duplicates. The amount of methylene blue
adsorbed at equilibrium per unit mass of biosorbent was determined according to the following equation