Adsorption of ionic liquid from aqueous solutions using functional corncob-cellulose nanocrystals

Abstract

Here we report novel adsorbents, based on corncob-cellulose nanocrystals, for the efficient absorption of ionic liquid (1-butyl-3-methylimidazolium chloride, [Bmim]Cl) from aqueous solutions. Diethylenetriaminepentaacetic acid (DTPA) and sulfosalicylic acid (SSA) were introduced onto the cellulose nanocrystals to improve their adsorption efficiencies. The maximum [Bmim]Cl adsorption capacities of the corncob cellulose nanocrystal–GMA–DTPA adsorbent (CNGD) and the corncob cellulose nanocrystal–GMA–SSA adsorbent (CNGS) reached 0.473 mmol g⁻¹ and 0.499 mmol g⁻¹, respectively, which are higher than those of many other reported adsorbents. Moreover, the monolayer adsorption of [Bmim]Cl onto the functional cellulose nanocrystal adsorbents was revealed by a better fitting of the Langmuir model. Adsorption kinetics studies indicated that the adsorption behavior of [Bmim]Cl followed a pseudo-second-order kinetics model. Furthermore, the reusability performances and cycling behaviors confirmed the promising potential of the novel biosorbents for the removal of [Bmim]Cl from aqueous environments.