A regenerable ion-imprinted magnetic biocomposite for selective adsorption and detection of Pb2+ in aqueous solution

A regenerable ion-imprinted magnetic biocomposite (IIMB) was successfully synthesized for simultaneous removal of Pb2+ using Serratia marcescens and carboxymethyl chitosan (CMC) as functional carriers, Pb2+ was utilized as the imprinted ion, while Fe3O4 served as the magnetic component. The structure and properties of IIMB were characterized by various techniques. The adsorption kinetics, isotherms and thermodynamics were applied to interpret the Pb2+ adsorption process on IIMB. The results showed the IIMB possessed prominent uptake ability toward Pb2+. The pseudo-second-order kinetic (R-2 = 0.9989) and Langmuir models (R-2 = 0.9555) fitted the data well. Adsorption thermodynamics revealed that the adsorption was a spontaneous endothermic reaction. The possible adsorption mechanisms involved physical adsorption, electrostatic attraction and complexing. Moreover, because Pb2+ can be specifically and strongly adsorbed on IIMB, a simple method for detection of Pb2+ was established by coupling IIMB with flame atomic absorption spectrometry (IIMB-FAAS). The developed IIMB-FAAS assay can sensitively detect Pb2+ with a linear range from 5.0 to 500.0 mu g/L. The detection limit (LOD) of 0.95 mu g/L as well as a quantification limit (LOQ) of 3.20 mu g/L were obtained. This work proved that the IIMB could selective and efficient adsorb Pb2+, which provided some insights into wastewater treatment, water quality inspection and environmental remediation.