Kinetics of the photodegradation of substituted phenols by solution combustion synthesized TiO_2

摘要

A nano-sized,high surface area phase pure anatase TiO2 synthesized by the solution combustion method was used to study the photo-catalytic degradation of various chlorophenols and methylphenols.The photocatalytic degradation rates of o-chlorophenol,p-chlorophenol,dichlorophenol,trichlorophenol,pentachlorophenol,o- and m-methylphenol (cresol) under UV exposure were determined using the combustion synthesized TiO2 and compared with the degradation rates with commercial Degussa P-25.The chlorophenols degraded much faster than the methylphenols,which degraded faster than phenol.The photocatalytic activity of combustion synthesized TiO_2 was significantly higher than that of Degussa P-25 under similar conditions.No intermediates were observed when combustion synthesized TiO_2 catalyst was used for the photocatalytic degradation of the phenols,while several intermediates were observed for the same reactions catalyzed by Degussa P-25.Because some of the intermediates are toxic,combustion synthesized TiO_2 may be more beneficial in environmental catalysis.The mechanisms for the photocatalytic degradation were proposed and the kinetic parameters were determined by regressing the experimental data.