ZnO nanoparticles photocatalytic activity toward atmospheric toluene under simulated sunlight

In this study, the photocatalytic degradation of toluene through zinc oxide (ZnO) nanoparticles coated on glass plates was examined under simulated sunlight. Heat attachment procedure was employed to immobilize ZnO nanoparticles on glass plates. Removal performance of these prepared plates for toluene degradation was evaluated in a rectangular reactor under irradiation of metal halide lamp. The effects of operational parameters including initial toluene concentration, temperature, relative humidity, irradiation time, and concentration of zinc oxide suspension on the removal of toluene were investigated. The structural properties of ZnO nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The concentration of toluene was analyzed by gas chromatography with flame ionization detector (GC-FID). The results of the present study indicated that ZnO-coated glass plates resulted in removal of 67% toluene for concentration of 50 ppm at temperature 45 degrees C, and relative humidity of 40% after 240 min irradiation of metal halide light. As the glass plates coated by ZnO have relatively good performance under experimental conditions, it concluded that coating ZnO nanoparticles on surfaces can be considered as an environmentally friendly method to eliminate low concentration of toluene from polluted air under sunlight.