Degradation of sulfamethoxazole by photocatalysis using supported TiO2

International audienceIn the present work, the efficiency of UV-A/TiO2 photocatalytic process to remove sulfamethoxa-zole (SMX) from aqueous solution was investigated using TiO2 Degussa P25 and TiO2 Millennium PC500 immobilized on glass plates. The effects of operating parameters such as initial SMX concentration (10-50 mg L-1), initial pH value (3-9), flow rate of the reactor (0.11-0.48 L min-1) and visible irradiation on process efficiency were studied. All experiments were performed on a fixed-bed recirculating photoreactor. The optimal condition for the SMX removal was obtained at low SMX initial concentration and nearly complete SMX degradation was attained after 7 h irradiation at 10 mg L-1 with TiO2 Degussa P25.The SMX degradation was not affected by the variation of the initial pH of the solution. The effect of flow rate showed that there was no significant impact of this variable on the degradation of SMX, which eliminates the influence of diffusion limitation.Photodegradation seems to follow the Langmuir Hinshelwood pseudo first order kinetic model. The apparent rate constants were found to be 0.008 and 0.003 min-1 under UV irradiation for TiO2 Degussa P25 and TiO2 Millennium PC500, respectively. The obtained results show that supported TiO2 Degussa P25 is more active than supported TiO2 500