Removal of Carbonyl-Containing Effluents by Photodegradation Using β-Carotene Embedded onto Zinc Oxide Particles

Abstract

Abstract: Environmental pollution especially in the form of effluent wastewater from industries has been a major challenge. Carbonyl-containing organic standards and sewage sample were effectively photo degraded. ZnO nanoparticles were prepared by emulsification of zinc-carbamate solution using 1 N NaOH and grafted chemically by Molecular Layer Doping method at 180 °C with β-carotene extracted using methanol by refluxing at 50 °C at varying concentrations. Intrinsic and grafted β-carotene ZnO were characterized using FTIR (Fourier transform infrared spectroscopy) and their spectra differed in an additional peak at around 1,435 nm corresponding to the organ metallic bond Zn-C. UV-Vis spectra of the two composites indicated a blue shift in the grafted samples. This translated to a reduced band gap from 3.5 eV to 3.4 eV. Comparison in the rates of photodegradation of pure organic compounds, organic effluents and color change of dyes was in the order 1% grafted, 0.5% grafted, intrinsic ZnO and blank sample. When 10.0 mL of sewerage water was photo degraded using both sunlight and UV-Lamp for 40 minutes, the amount of carbonyls present decreased by 28.5% for β-carotene grafted ZnO, 24.5% for intrinsic ZnO and 0.6% for a blank sample. Key words: Intrinsic ZnO, β-carotene, organic effluents, carbonyls, photo-degradation.