Abstract
An effective and selective ion-imprinted biosorbent was prepared from chitosan, using Pb(II) ions as templates and ethylene glycol diglycidyl ether as the crosslinker. The resultant Pb(II)-imprinted chitosan beads (Pb-ICB) were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The adsorption property and selectivity of Pb-ICB were evaluated for the adsorption of Pb(II). The results showed that Pb-ICB had more cavities, but lower crystallinity and thermal stability than non-imprinted chitosan beads (NICB). Much higher adsorption capacity in the single metal system and better selectivity in the binary metal system for the adsorption Pb(II) were achieved with Pb-ICB than NICB. The maximum adsorption capacity of Pb(II) on Pb-ICB reached 177.62 mg/g. The kinetic and isothermal analyzes showed that the adsorption process of Pb(II) onto Pb-ICB well-fitted pseudo-second-order kinetic and Langmuir isotherm models. The thermodynamic analysis revealed that the adsorption of Pb(II) onto Pb-ICB was a spontaneous and endothermic process. Furthermore, Pb-ICB showed good reusability within five cycles of adsorption–desorption.
Acknowledgments
This work was supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, Department of Human Resources and Social Security of Hebei Province, China.