Comparative study of immobilized N-doped TiO2 based novel multistage fixed-bed and conventional packed-bed photoreactors on the degradation of an emerging contaminant

摘要

In the present study, the performance of a novel multistage fixed-bed photoreactor developed from immobilized N-doped TiO2 nanoparticles was investigated and compared with the conventional packed bed photoreactor using Bisphenol-A as a model contaminant in a batch recirculating mode. The effects of selected operational parameters such as irradiation time, initial Bisphenol-A concentration, light intensity and flowrate were studied in the range of 45 to 180 min, 5 to 20 mg/L, 1.2 to 4.8 x 10(6) photons/s and 10 to 40 mL/min, respectively. Results show the photodegradation efficiency and total organic carbon (TOC) removal of both photoreactors increased with irradiation time and light intensity, and decreased with initial Bisphenol-A concentration and flowrate. Highest degradation efficiencies for both reactors, although to different degrees, were recorded at irradiation time of 180 min, initial Bisphenol-A concentration of 5 mg/L, light intensity of 4.8 x 10(6) photons/s and flowrate of 10 mL/min. Furthermore, the photodegradation kinetics of the reactors was compared at the optimum condition by assuming pseudo-first-order reaction kinetics. Results showed that the reaction rate of the novel multistage fixed bed photoreactor was more than double that of the conventional packed bed photoreactor. In general, in all selected operational parameters the novel photoreactor showed improved performances over the conventional packed bed photoreactor.