Applied Surface Science, Vol.404, 418-425, 2017
Adsorptive removal of Cr3+ from aqueous solutions using chitosan microfibers immobilized with plant polyphenols as biosorbents with high capacity and selectivity
A novel biosorbent was facilely prepared by immobilizing bayberry tannin (BT, a typical natural polyphenols) onto chitosan microfiber (CM). The as-prepared CM-BT adsorbent featured to a well-defined microfibrous morphology and highly distributed adsorption sites, which was highly efficient and selective for the adsorptive removal of Cr3+ from aqueous solutions. Based on batch experiments, the adsorption of Cr3+ on CM-BT was pH-dependent, and the optimized adsorption pH was determined to be 5.5. The adsorption capacity of CM-BT to Cr3+ was high up to 20.90 mg/g. The co-existing cations, such as Mg2+, Ca2+, Fe3+ and Cu2+, exhibited no significant influences on the adsorption of Cr3+ on CM-BT. The adsorption kinetics were well fitted by the pseudo-second-order rate model (R-2 > 0.99) while the adsorption isotherms were well described by the Langmuir model (R-2 > 0.98). Importantly, CM-BT was effective for the continues treatment of low concentration Cr3+ (2.0 mg/L) contaminated wastewater. Before reached the breakthrough point (5% of the initial Cr3+ concentration, 0.1 mg/L), the treated volume was as high as 894 bed volume, manifesting the great potential of CM-BT in practical treatment of Cr3+ contaminated wastewater. (C) 2017 Elsevier B.V. All rights reserved.
Keywords:Chitosan microfibers;Plant polyphenols;Low concentration of Cr3+;High capacity and selectivity;Column treatment