Growth and characterization of nanostructured Ag-ZnO for application in water purification

In this work, a low-cost method to produce ZnO nanostructured materials for the treatment of water polluted with model organic pollutants (e.g. dyes) is presented. Zinc and silvercoated Zn (Ag/Zn) films, fabricated via sputtering method were naturally oxidized via a simple, low-temperature, scalable thermal process. During oxidation, Ag/ZnO nanorods were grown on Zn foils after treating their surface with various agents (e.g. acids) and annealing in an oven at temperatures 385-400 °C. The ZnO and Ag/ZnO films on Zn were characterized by X-ray diffraction, scanning electron microscopy and photoluminescence spectroscopy. The cationic dye methylene blue (MB) was selected as model pollutant dissolved in water. A batch photo-reactor was fabricated and used to to study the adsorption capacity and photocatalytic performance of films. The transient varation of MB concentration in aqueous solutions was measured with ultraviolet-visible (UV-Vis.) spectroscopy. Ag/ZnO demonstrated a strong MB adsorbion capacity in dark conditions, and a satisfactory MB photocatalytic degradation under UV light irradiation.The optimized doping of Ag in Ag/ZnO film enhanced its photocatalytic activity, and seems well-promising for the potential scale-up of Ag/ZnO films, and use in large-scale systems for water purification under UV light irradiation. © 2020 Trans Tech Publications Ltd, Switzerland.