Organic dyes are among the main sources of water pollution that cause serious health problems for living organisms. Removing dye pollution from water sources is important because of its high toxicity, so it has attracted the interest of researchers. Heterogeneous photocatalysis based on ZnO is one of the most important methods of pollution treatment. The purpose of this review is to summarize the use of ZnO nanostructure and ZnO modified as photocatalysts.The studied mechanism of dye photocatalytic activity and the most important factors affecting the photocatalytic process are discussed. The major effective parameters associated with the surface and morphology to look upon for the efficient photodegradation of organic pollution are structural and average particle size, surface area, band gap crystalline structure, surface density, and porosity. The photodegradation reactions depend on the state of ionization as well as on the surface charge of the photocatalyst and organic dye because pH will determine the charge of the catalyst according to the medium. On the other hand, the calcination temperature was increased throughout the work to break down the pores, which reduces the surface area of the synthesis photocatalyst. The type of dye has an important influence on the success of the photocatalytic process. تفاصيل المقالة

Chemical bath deposition (CBD) was used to prepare titanium dioxide (TiO2) nanocrystalline thin films on glass substrates. The TiO2 nanocrystalline thin films were created, and the Scanning Electron Microscope (SEM) images showed that they developed as nanoflowers and tiny semi-nanoplate bundles that grew vertically onto the surface of the substrates with uniform distribution. The nanoplate ranges in length from 26 to 149 nm and the average thickness was between 13 and 228 nm. The prepared TiO2 nanoflower thin films have an energy band gap of 3.26 eV, according to optical characteristics. Using various pH values and UV light exposure durations, the photocatalytic activity of the produced TiO2 nanoflower thin films was examined against the methylene blue (MB) dye at room temperature. When irradiation duration and pH were increased, the photodegradation rate of MB dye also increased. After 240 minutes of exposure, the photodegradation rate of MB dye with pH values of 6, 8, 9, 10, and 11 was 51%, 64%, 79%, and 82%, respectively. The kinetic rate constant for photocatalytic degradation of MB dye was determined to be 0.0069, 0.0061, 0.0038, and 0.0028 min-1 for pH values of 11, 9, 8, and 6, respectively. تفاصيل المقالة