Adsorption and photocatalytic removal of SO2 using natural and synthetic zeolites-supported TiO2 in a solar parabolic trough collector

Abstract

Performance of adsorption and photocatalysis processes for SO2 removal was studied using a new synthetic zeolite prepared from stone cutting sludge and a natural zeolite (clinoptilolite) as the supports of TiO2 photocatalyst under different sunlight irradiation intensities in a photoreactor equipped with parabolic trough collector. The samples were characterized by X-ray fluorescence spectrometer, X-ray diffraction, surface area, fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, UV–Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The optimum sunlight irradiation for SO2 photodegradation was observed around the noonday with the high light intensity (125.0–135.0 mWcm−2) resulted in about 35% removal efficiency. The highest SO2 removal by adsorption was 31.7% and 27.6% for TiO2-natural and synthetic zeolites, respectively. The maximum SO2 removal efficiency by the composites of TiO2-Ze and TiO2-Cp through the adsorption and photocatalytic processes was 70.0% and 78.8%, respectively. The regeneration of composite by washing with water was the simple and cost-effective method with more than 95% efficiency. Overall, both natural and synthetic zeolites could be used as efficient supports of TiO2 photocatalysts for the removal of SO2 under sunlight irradiation.