Removal of V (V) and Pb (II) by nanosized TiO₂ and ZnO from aqueous solution

The removal of V (V) and Pb (II) by TiO₂ and ZnO nanoparticles from aqueous solution was studied with batch experiments. Atomic force microscopy (AFM), fourier Transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface properties including functional groups of the adsorbent as well as to explore adsorption mechanisms. Factors influencing V (V) and Pb (II) removal such as initial metal ion concentration and contact time were investigated. The kinetics of V (V) and Pb (II) removal occurred quickly and > 90% of the metals was removed within 30 min for both nanoparticles. Maximum adsorption of V (V) and Pb (II) onto TiO₂ and ZnO nanoparticles was observed at temperature of 298 K and pH 6.5 ± 0.1. The removal characteristics of the metals by the two nanoparticles were similar. A comparison of the kinetic models against experimental data showed that the kinetics react system was best described by the pseudo-second-order model. V (V) and Pb (II) reacted with functional groups, which led to the formation of polytype Pb-O bond and hydroxyl-vanadium complexes. The experimental data also confirmed the formation of heavy metal-OH sorption complexes on the adsorbent surfaces. This research enhanced current understanding of the removal of V (V) and Pb (II) by nanosized TiO₂ and ZnO from contaminated water.