| Using tubular reactor with thin TiO2 film coated in the inner wall, degradation degree of formaldehyde by photocatalyst reaction of TiO2 nanoparticles synthesized in propane/air flame was measured. Effects of superficial gas velocity, film thickness, wavelength and light strength, relative humidity, and formaldehyde concentration have been investigated experimentally. Experimental results showed that at the experimental conditions of 3.4s in residence time, effective film thickness of about 100nm, inlet formaldehyde concentration of about 500ppm, a 254nm and a 365nm 8W UV lamps, ambient temperature and pressure, 0-30% degradation degree have been obtained for 16 TiO2 nanoparticles synthesized in propane/air flame at different operational conditions. Diffusion equation has been integrated numerically by the Roung-Kutta method and 1st order rate constant of the photocatalyst reaction has been obtained. In the experimental conditions of 3.4s in residence time, effective film thickness of about 100nm, inlet formaldehyde concentration of about 500ppm, a 254nm and a 365nm 8W UV lamps, ambient temperature and pressure, 1.37·10-4 -1.17·10-3m/s of 1st order rate constant were achieved. Effects of rutile content and carbon content on degradation degree and 1st order rate constant were discussed. Results showed that degradation degree and 1st order rate constant increases with increasing rutile content for rutile content in a range of less than 30%, and has maximum at carbon content of about 5%. |
