High efficient removal of lead from aqueous solution by preparation of novel PPG-nZVI beads as sorbents

Polyvinyl alcohol and pumice synthetized guar gum-nanoscale zerovalent iron beads (PPG-nZVI beads) were first prepared by flocculation reaction for removal of Pb2+ from water. The PPG-nZVI beads could overcome major challenges of nZVI for in situ remediation such as mobility, agglomeration, and oxidation. The batch experiments show that the removal capacity for Pb2+ increases with the augmentation of PPG-nZVI beads dosage but has a decreasing tendency when the initial concentration of Pb2+ and ionic strength turns greater. The results show that there is no difference between the reaction rates of bare and entrapped nZVI. The FTIR and XPS analyses indicate that the removal of Pb2+ is caused by adsorption and co-precipitation. The adsorption kinetics data of Pb2+ to PPG-nZVI beads fit well with the second order model. The sorption isotherm can be described by Langmuir model and the maximum adsorption capacity of PPG-nZVI beads is 59.82 mg g(-1). The PPG-nZVI beads can be provided as promising materials for in situ Pb2+ remediation. (C) 2016 Elsevier B.V. All rights reserved.