Photocatalytic degradation of acetone and methanol in a flow-through photoreactor with immobilized TiO2

Volatile organic compounds must be used in many industrial processes, involving their emission to the environment in gaseous form. This paper describes the degradation of vapors of acetone and methanol in air by photocatalysis. To achieve this, a tubular flow-through reactor with TiO2 photocatalyst irradiated by either UV-A or UV-C lamps is used. The irradiation wavelength was the main studied parameter. Equal volumetric feed of liquid in the air stream for both pollutants resulted in a concentration of acetone of about 275 ppm and of methanol of about 500 ppm. In separate experiments, using the UV-A lamps, the conversion of acetone was 29 %, while for methanol it was 72 %. The faster oxidation of methanol relative to acetone can be explained by their different molecular structure. For UV-C lamps, the conversion of acetone significantly increased (to 60 %), while that of methanol increased only slightly (to 80 %). The contribution of photolysis to the degradation of both compounds was considered and finally evaluated to be negligible in this setup.