Structural, electronic and optical properties of ZnO and TiO2 nanoparticles for wastewater treatment: A first-principles study

Abstract

Water quality deteriorates when industrial and human activities increase. This means that toxins must be removed from industrial and domestic wastewater. In the context of nanotechnology, anchoring TiO2 and ZnO nanoparticles on clay has also been shown to be potential sequesters and has been examined for wastewater treatment. This paper presents a thorough investigation of the structural, electronic, and optical featuresof ZnO & TiO2 nanoparticles using the GGA-PBE functional within the framework of density functional theory (DFT). For ZnO and TiO2 nanoparticles, there is excellent agreement between the calculated lattice parameters and the findings of the experiments. Electronic structure calculations confirm that both ZnO and TiO2 are semiconducting in nature. The density of states calculation reveals that the conduction band in TiO2 is primarily derived from hybridization between Ti-3d states and O-2p states, whereas the valence band is derived from mixing between Ti-3d and O-2p states. Further, ZnO, O-2p, andZn-3d states, primarily contributed to the valence band, while Zn-4 s and Zn-3p states mainly contributed to the conduction band. Since drinking water disinfection processes frequently involve ultraviolet (UV) absorption based advanced oxidation process. Investigations of the optical properties of these two materials suggest that ZnO and TiO2 show great potential as strong UV-absorbing and photocatalytic materials, and can be utilized as microbial disinfectants during wastewater treatment.