Removal of styrene by the synthesized ZnO nanoparticles coated on the activated carbon adsorbent in the presence of UV irradiation

Abstract

Background: Volatile organic compounds are the major environmental pollutants causing adverse effects on the human health and the environment, therefore, tremendous effort has been put toward eliminating these compounds. Methods: In this study, the effect of synthesized nanoparticles on the removal of styrene from gas phase by photocatalytic process under UV irradiation in the cylindrical photoreactor was studied. The activated carbon-zinc oxide (AC-ZnO) catalysts were prepared at different weight ratios (6%, 12%, and 18%) of ZnO. The prepared catalyst was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Brunauer-Emmett-Teller (BET) analyses. The effects of various parameters, such as concentrations of styrene, various weight percentage (wt%) of nanoparticles, and UV irradiation, were investigated. The efficiency of the AC-ZnO catalyst was determined based on its adsorption capacity, breakthrough time, and removal efficiency. Results: It was revealed that the photocatalytic removal efficiency of styrene was high in the presence of both ZnO nanoparticle and AC under UV light. Under optimal conditions, the efficiency of UV/ACZnO 18%, UV/AC-ZnO 12%, and UV/AC-ZnO 6% catalysts was 77%, 86%, and 83%, respectively. By increasing the concentration of input styrene, the photocatalytic removal efficiency was reduced, while the adsorption capacity of styrene increased. Conclusion: According to the results, the AC-ZnO 12% exhibited higher activity compared to other photocatalysts. Also, the amount of stabilized ZnO nanoparticles on the activated carbon affects the elimination rate of styrene.

Synthesis, characteristics, and photocatalytic activity of zinc oxide nanoparticles stabilized on the stone surface for degradation of metronidazole from aqueous solution

“…Wang et al in their study on the synthesis of ZnO nanoparticles by hydrothermal synthesis method found similar results, which is consistent with the results of this study (24). In the investigation of TEM images, the small size of ZnO nanoparticles confirmed that a high specific surface area could show a good catalytic activity (15,20). The EDS spectrum of ZnO nanoparticles shows four peaks, which are identified as Zn and O.…”

“…In the last two decades, photocatalysts using semiconductor materials such as ZnO have attracted special attention due to their high optical sensitivity, high stability wide band gap and high efficiency in electron production. Using these nanoparticles, the energy Gap's property can adsorb a wide range of UV (19)(20)(21). Because of the extensiveness of nanoparticles and their applications, different methods are used for their production, the choice of which depends on the kind of materials and their application (22,23).…”