Efficient mineralization of bisphenol A by photocatalytic ozonation with TiO2-graphene hybrid

In this paper, the catalytic ability of TiO2-reduced graphene oxide hybrid (TiO2-RGO) in photocatalysis and ozonation combined system was investigated. TiO2-RGO hybrid was prepared by liquid-phase deposition (LPD) method. TEM, XRD, FT-IR, UV-vis spectra were used to characterize the structure and optical property. Photoluminescence (PL) spectra demonstrate that the recombination of photogenerated charges is greatly inhibited by introduction of RGO. Bisphenol A (BPA) was used as model substances to evaluate the catalytic ability of TiO2-RGO. The effect of RGO content and stability of TiO2-RGO in photocatalytic ozonation was also studied. The results showed that photocatalytic ozonation of BPA with TiO2-RGO hybrid was a very effective method for BPA mineralization. The TOC removal efficiency reached 98.4% by TiO2-RGO/O-3/UV in 45 min, which is 1.17 times as great as that of TiO2/O-3/UV process. Moreover, the catalytic ability of TiO2-RGO hybrid was very stable after recycling for five consecutive runs. This improvement is attributed to the improved separation efficiency of photo-generated charges, which facilitated the electrons trapping by ozone and enhanced the yield of hydroxyl radical. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.