Adsorption of Methylene Blue from Aqueous Solution by Crosslinked Chitosan/Bentonite Composite

This article reports the application of a crosslinked chitosan/bentonite composite as adsorbent for the removal of a cationic dye, methylene blue (MB), from aqueous solution. Batch experiments were conducted to study the effects of contact time, initial concentration of adsorbate (50-200 mgL(-1)), temperature (298-313 K), agitation speed (90-150 rpm), and pH (2-10) on adsorption. The equilibrium experimental data were analyzed by the Freundlich and Langmuir models. The kinetic data obtained with different initial concentration and temperature were analyzed using a pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations. Maximum adsorption capacity (Q(m)) was calculated at different temperatures (298, 308, and 313 K) as 95.24, 97.09, and 142.86 mg g(-1), respectively. The results showed that this novel adsorbent had a high adsorption capacity, making it suitable for use in the treatment MB-enriched wastewater.