Adsorption of Pb2+from aqueous solution by β-cyclodextrin/wood flour grafted copolymer: Kinetic and thermodynamic studies

Document Type

Article

Publication Date

4-1-2013

Abstract

β-cyclodextrin/wood flour (β-CD/WF) grafted copolymer was prepared by esterification-crosslinking technology, i.e., grafting β-CD onto poplar wood flour in the presence of citric acid. The properties of this grafted copolymer were characterized by FT-IR, TGA and the technique of phenolphthalein probe respectively. The adsorption property of this copolymer for Pb2+ in a batch adsorption system as a function of contact time, pH and initial Pb2+ concentration was investigated in this study. The results showed that β-CD was not only grafted onto the surface of wood flour but also demonstrated an encapsulation activity. The kinetic data were analyzed by the pseudo-first, second-order kinetics and intraparticle diffusion, and the equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The results showed that adsorption equilibrium was reached within 30 min at 298 K under the proper pH between 4.0 and 8.0, and the adsorption capacity increased with the rise of initial Pb2+ concentration. It was found that the adsorption kinetics followed the second-order model. This suggested that the adsorption of Pb2+ by copolymer was a chemisorption process, and the intraparticle diffusion was not the primary rate-determining step. Besides, Langmuir model fitted the equilibrium data better than the Freundlich isotherm. It reflected the adsorption of Pb2+ on copolymer was monolayer adsorption. The thermodynamic properties, ΔG⊖, ΔH⊖ and ΔS⊖ showed that adsorption of Pb2+ onto β-CD/WF flour grafted copolymer was endothermic and spontaneous in the temperature range of 293-313 K.

Publication Source (Journal or Book title)

Chemistry and Industry of Forest Products

First Page

1

Last Page

9

This document is currently not available here.

Share

COinS