Highly efficient and selective removal of trace lead from aqueous solutions by hollow mesoporous silica loaded with molecularly imprinted polymers.

A novel type of adsorbent for the selective recognition and adsorption of trace Pb from aqueous solutions has been successfully constructed simply by grafting molecularly imprinted polymers (MIPs) onto hollow mesoporous silica (HMS). Attractively, the HMS loaded with MIPs (H-MIPs) exhibits a fast adsorption kinetics, marked adsorption capacity of 40.52mg/g and extremely high selectivity toward Pb over Cu, Zn, Co, Mn and Ni, and the selectivity coefficients have been determined to be as high as 50. Moreover, such high adsorptive capability and selectivity were retained for at least 6 runs, indicating the stability and reusability of H-MIPs. Lead ion contaminants in real water samples were successfully concentrated and approximately 100% recovered using H-MIPs. Theoretical analysis shows that the adsorption process of H-MIPs follows the pseudo-second-order kinetic and Langmuir isotherm models. These demonstrate that H-MIPs are greatly potential for the rapid and highly efficient removal of trace Pb ions in complicated matrices.