Visible-Light Induced Degradation of Norfloxacin and Methylene Blue Using Easily Recoverable NiO/ZnO Heterostructures: Analysis of Efficacy, Stability, Reaction Mechanism and Degradation Pathway

The treatment of wastewater through the use of photocatalytic materials over semiconducting metal oxide has gained widespread interest as a promising new green and cheap technology. For the first time norfloxacin (NOR) antibiotic and methylene blue (MB) dye degradation was achieved by a simpler, cheaper, and faster technique for the preparation of NiO/ZnO heterostructure via NiO and its combined forms with ZnO catalysts under hydrothermal process. X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and X-ray photoelectron (XPS) spectroscopy were the techniques that were used to analyze the structure, morphology, and elemental contents, respectively. The Tauc plot using absorption spectra was used to determine the band energy value of pure NiO, ZnO, and NiO-ZnO catalysts. The results showed that the energy band gap of these materials was 3.15, 3.38, and 2.93 eV, respectively. All photocatalysts performed good efficiency within 50 min of irradiation, among these NiO/ZnO having superior activity (30 mg of catalyst, and 10 & mu;M of dye and antibiotic). Under these conditions, the photocatalytic degradation efficiency of the produced NiO/ZnO materials for the NOR and MB dye was achieved at 96.73% and 97.38%, respectively. Inhibition of the recombination of electron-hole pairs by charge transfer processes may account for the high activity of the p-n-type NiO/ZnO heterostructures for the degradation of NOR and MB. Because of their strong photocatalytic activity, heterostructures based on semiconducting composites, such as NiO/ZnO, have great promise for use in future manufacturing processes aimed at cleaning our surroundings of harmful organic pollutants.