TiO2microspheres have been employed as a promisingly new photocatalyst for water and wastewatertreatment. P25 TiO2is commonly employed and its properties are well established as photocatalyst. Inthis study, photocatalytic activities of the two TiO2samples are compared by degrading sulfosalicylicacid (SSA), phenol, and 2,4-Dichlorophenoxyacetic acid (2,4-D) under 365 nm UV illumination in a sus-pension system at neutral pH and associated optimized TiO2dosages. The results showed that the threeorganic compounds unexceptionally degraded more rapidly on P25 than on TiO2microspheres in termsof the concentration-time curves and total organic carbon removals at 120 min. This might me attributedthe presence of oxygen vacancies and Ti(III) defects already present on P25 as determined by electronparamagnetic resonance, implying that the defects played an important role for the enhancement of thecharge transfer step as rate-determining step. The degradations of three organic compounds on P25 andTiO2microspheres could be well described by the first-order rate equation, while the degradation kineticsof SSA on TiO2microspheres was quite different. The difference was ascribed to the medium adsorptionability of SSA on the TiO2surface. © 2014 Elsevier B.V. All rights reserved.