Photocatalytic degradation of gaseous acetone, toluene, and p-xylene using a TiO2 thin film

Abstract

A nano-structured TiO2 thin film immobilized on glass springs was prepared by the sol-gel method, and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Acetone, toluene and p-xylene were chosen as common VOCs for a photocatalytic degradation study of both mixed and pure gases using the TiO2 thin film. Addition of hydrogen peroxide promoted activation of the catalyst during acetone degradation. The effects of gas flow rate and UV light wavelength were investigated with the pure gases. Gas flow rate greatly influenced the degradation. The highest degradation rates were 77.7% (at 3 L/min) for acetone, 61.9% (at 3 L/min) for toluene, and 55% (at 7 L/min) for p-xylene. A UV light wavelength of 254 nm provided greater degradation of the VOCs than 365 nm UV light. The degradation rates of p-xylene and acetone in the gas mixture were lower than those of pure p-xylene and acetone. The opposite trend was observed for toluene. Acetone, both in the mixed gas and pure, had the highest degradation efficiency. Acetone, toluene and p-xylene degradation followed Langmuir-Hinshelwood kinetics.