Ag-Li-ZnO nanostructures for efficient photocatalytic degradation of organic dyes and textile wastewater under visible light treatment

The study describes the preparation and characterization of pure ZnO, Li-ZnO (LZO), Ag-ZnO (AZO) and Ag-LiZnO (ALZO) nanostructures by sol -gel method, followed by their application as photocatalysts for the degradation of dyes acid red (AR1), mordant orange (MO1) and textile wastewater (TWW) under irradiation of visible light. The ALZO composite showed the highest photocatalytic efficiency among the tested samples with 95% degradation of dyes, which was three times higher than that of pure ZnO. The degradation reaction followed pseudo-first-order kinetics and the control trapping experiments corroborated the reactive species are hydroxyl radicals. The study also investigated the influence of various operational parameters on the photodegradation of dyes. The high photocatalytic efficiency of the ALZO material is mainly due to its highly porous structure with greater surface area, enhanced absorption of visible light, and a decreased recombination rate of electron-hole pairs. The ALZO catalyst had a band gap energy of 2.82 eV and exhibited the wurtzite ZnO hexagonal phase. The study highlights the effectiveness of doping metal oxides into semiconductor oxides to enhance photocatalytic activity and suggests the potential of the ALZO composite as a promising photocatalyst for dye degradation.