Adsorption isotherms and kinetics studies of malachite green on chitin hydrogels

► The chitin hydrogels were successfully prepared from chitin solution in 8 wt% NaOH/4 wt% urea aqueous system by crosslinking with 5 wt% epichlorohydrin. ► The chitin hydrogels exhibited high efficiency to remove dye (malachite green) from aqueous solution, as a result of their microporous structure, large surface area and affinity on the dye. ► The activation energy calculated from Arrhenius equation and the result of SEM and FTIR indicated that the adsorption of malachite green on the chitin hydrogels was physical process.