Adsorption and mechanism study for reactive red 120 dye removal by cross-linked chitosan-epichlorohydrin biobeads

In this research, cross-linked chitosan-epichlorohydrin biobeads (CEB) were prepared to be potential biosorbent for reactive red 120 (RR120) dye removal from aqueous solution. Adsorption experiments were carried out as a function of contact time (0-600 min), initial dye concentration (30-400 mg/L), and pH (3-12). The adsorption data of RR120 on CEB were in agreement with Langmuir isotherm. The adsorption capacity of CEB for RR120 was 81.3 mg/g at 303 K. The kinetic data were well described by pseudo-second-order kinetic model. The adsorption process was spontaneous and endothermic in nature. The mechanism of adsorption included mainly hydrogen bonding interaction, electrostatic attractions, and n-pi stacking interaction. This study reveals that the CEB as a promising biomaterial for removal of reactive dye from aqueous solutions.