Photoreduction of Cr(VI) in water using Bi_2O_3-ZrO_2 nanocomposite under visible light irradiation

摘要

Chromium(VI) is a common heavy metal pollutant and extensively used in variety of industrial processes. In the present study, bismuth oxide-zirconium oxide nanocomposite (Bi_2O_3-ZrO_2) was synthesized to improve photoreduction of Cr(VI) under visible light irradiation. The synthesized photocatalyst was characterized by UV-visible-diffuse reflectance spectroscopy (UV-vis-DRS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (B.E.T) surface area analysis and photoluminescence spectroscopy (PL). Bi_2O_3-ZrO_2 was found to be more photoactive than Bi_2O_3, ZrO_2, TiO_2 and ZnO for the reduction of Cr (VI). The influences of various reaction parameters like the effect of catalyst concentration, initial Cr(VI) concentration and addition of inorganic salts on the photocatalytic activity have been investigated in detail. Meanwhile, the stability of Bi_2O_3-ZrO_2 was investigated by repeatedly performing Cr(VI) photoreducing experiments.