Visible light induced photocatalytic reduction of Cr(VI) over polymer-sensitized TiO2 and its synergism with phenol oxidation

Abstract

In this study, both Cr(VI) reduction and phenol oxidation induced by polymer-sensitized TiO(2) were investigated under visible light. Study of the reaction mechanism indicated that poly(fluorene-co-thiophene) (PFT) acted as a semiconductor and was by itself able to reduce Cr(VI) under visible light irradiation. When coupled with TiO(2), PFT served not only as the electron donor for Cr(VI) reduction, but also as a sensitizer. Upon irradiation by visible light, electrons in the sensitizing PFT polymer are excited and are transferred to the conduction band of TiO(2). PFT-catalyzed reduction of Cr(VI) was significantly promoted by the presence of phenol, and synergism between Cr(VI) reduction and phenol degradation was demonstrated both by analysis of the FT-IR spectrum of PFT/TiO(2) and by measuring the effect of repeated use of PFT/TiO(2) on its photocatalytic efficiency. The results provide a cost-effective method to remove organic and inorganic pollutants simultaneously in the complex wastewater.