Application of nickel oxide nanoparticles as reusable sorbent for the removal of lead ions from contaminated water

In this study, NiO nanopowder (NONP) is prepared using a sol-gel method based on polyvinyl alcohol (PVA) as gel precursor agent. The produced NONP is characterized by TGA, FTIR, TEM, SEM, DLS and XRD. The results show that the synthesized sample consists of uniform nanoparticles in the range of 10-25 nm with an average diameter of 15 and 20 nm based on the TEM micrograph and DLS results, respectively. The synthesized NONP is used as a new and efficient nanosorbent for the removal of heavy metal cations such as lead ions from solutions with high concentrations of pollution. Kinetic and equilibrium studies showed that the experimental data of Pb(II) ions were best described by pseudo-second-order and Langmuir isotherm models. The obtained results showed that the quantitative removal of Pb2+ ions can be performed under the optimized conditions, including 100 mu g ml(-1) initial concentration of lead ions with a pH of 5, 2.0 mg ml(-1) sorbent dosage and contact time of 1 h in room temperature. The maximum sorption capacity for Pb (II) on NONP is found to reach up to 50.7 mg g(-1). The experimental results indicate that the NONP can not only be used as a high performance nanosorbent for the removal of lead ions but also reused frequently without significant loss in sorption efficiency for five times.