Fabrication of Zinc Oxide/Reduced Graphene Oxide Nanocomposites (ZnO/rGO) for Efficient Photoactivation of Peroxymonosulfate: A Case Study on Degradation of Methyl Orange

The ZnO/rGO was synthesized by varying the ratios of rGO to 1%, 2%, and 3%. The as‐synthesized ZnO, rGO, and ZnO/rGO were examined using scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and ultraviolet‐diffuse reflectance spectroscopy (UV‐DRS). Under solar light illumination for 100 min, 68% of methyl orange (MO) was successfully removed by as‐synthesized ZrG3 (nanocomposite having 3% rGO) with the corresponding k app value of 0.0083 min −1 . Peroxymonosulfate (PMS) incorporation in to the reaction mixture significantly synergized the rate of MO breakdown. In the presence of PMS, the percent degradation of MO increased from 68% to 91% with the corresponding k app value of 0.019 min −1 . The photocatalytic breakdown of MO at pH = 6.8, 3.0, and 10.0 was observed to be 80%, 65%, and 72%, respectively. Experiments using radical scavengers demonstrated hydroxyl ( ● OH) and sulfate radicals (SO 4 ●– ) as the major species playing role in MO degradation. Furthermore, MO degradation was tested in a variety of water systems, such as distilled water, synthetic wastewater, and industrial wastewater samples. In light of this, the degradation by‐products (DPs) of MO and the mechanisms leading to them were suggested accordingly.