Photocatalytic degradation of anthracene in aqueous dispersion of metal oxides nanoparticles: Effect of different parameters

Contamination with anthracene, as one of polycyclic aromatic hydrocarbons (PAHs), was considered as an important health issue due to its carcinogenic and mutagenic activity. In this paper, we focused on the photocatalytic degradation of anthracene in different media and in presence of various photocatalysts. Zinc oxide nanoparticles (ZnO NPs) and nickel oxide nanoparticles (NiO NPs) were prepared and utilized as efficient photocatalysts to convert anthracene into safer compounds. The as-prepared photocatalysts were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-VIS spectroscopy. The factors affecting the efficiency of photocatalytic degradation, including irradiation time, loading catalyst doses, pH value and H2O2 as an oxidizing agent, were investigated. The optimum photocatalytic degradation of 23 mg/L anthracene in different media was carried out at pH 7.2 with loading catalyst dose of 55.6 mg/L. In case of anthracene emulsion solution, a faster photochemical kinetic was observed in presence of ZnO NPs and more than 90% of photocatalytic degradation percentage was reached in 230 min. However, in case of anthracene aqueous solution and in presence of ZnO NPs/H2O2, a degradation efficiency of 84% was obtained within 50 min. The byproducts of 4- formyl-benzoic acid ethyl ester (98.23%) and 1,2-Benzenedicarboxylic acid, isopropyl methyl ester (0.85%)) were detected by gas chromatography-mass spectrometry (GC–MS). The kinetic studies were achieved and revealed that the photocatalytic degradation process obeyed a Langmuir–Hinshelwood model and followed a pseudo-first order rate expression.