Zinc oxide quantum dots: Confinement size, photophysical and tunning optical properties effect on photodecontamination of industrial organic pollutants

Confinement size effect and tunning optical properties of Zinc oxide quantum dots (ZDs) observed via modified wet chemical preparation method. The purity, high crystallinity, and elongated structure of ZDs investigated by XRD and TEM tests. The crystallized size values, the bandgap energy, and the active surface area for ZD1 and ZD2 determined based on the TEMs, DRSs, and EBTs are 2.9 and 3.6 nm, 3.57 eV and 3.54 eV, and 312.10 m2/g and 278.05 m2/g, respectively. Absorption and fluorescence spectra shifted for ZDs from 340 to 315 nm and from 530 to 500 nm, respectively, due to its confinement effect of their small sizes. The prepared samples revealed that the photocatalytic activity of ZD1 is higher than ZD2 by 20%. Photocatalytic activity of ZDs by the photodegradation process of Coomassie Brilliant Blue R dye as an industrial organic pollutant evaluated (used in textile and dyeing manufactories) by xenon photoreactor and solar photocatalytic processes. The observed results have shown that photocatalytic efficiency increases with crystallite size decreasing. And, the variation between the photocatalytic activity of ZDs prepared samples by the solar photocatalytic process is higher than that observed by the Xenon photoreactor. And their photodegradation rates values are lower than that obtained by the Xenon photoreactor. A similar finding for the recycling process after nine reptation times of using ZDs during all photodegradation processes signified obtained.