Graphene oxide and chitosan composite material using as a high-efficiency and low-cost granular
adsorbent for methylene blue removal was fabricated via self-assembling method. The effects of
pH value, contact time, initial concentration, adsorbent dose, temperature, and recyclic stability
on the adsorption performance of methylene blue in aqueous solution were investigated in detail.
Desorption process with the effects of solvents, contact time, and temperature were also conducted carefully in this study. The adsorption kinetics and adsorption isotherm of dye adsorption
process showed that dye adsorption process was fitted to the pseudo-second-order kinetic model
and the Freundlich adsorption isotherm, indicating a physical adsorption process with multilayer
adsorption. The intra-particle diffusion model indicated that the dye adsorption by the granular
adsorbent was strongly happened during the first 4 h. The thermodynamic study showed that the
adsorption was a spontaneous and exothermic process and dye ions were condensed onto the
surface of adsorbent. The maximum adsorption capacity of dye on the granular adsorbent was
calculated as 951.35 mg/g and the adsorbent could maintain its adsorption performance after six
cycles. In general, this study provided an efficient, cost-effective, and recyclable the granular
adsorbent for dye separation from aqueous solution.