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

Abstract

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 mg L−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.