Photocatalytic degradation of bisphenol A by TiO2@aspartic acid-beta-cyclodextrin@reduced graphene oxide

In this work, a novel titanium dioxide@aspartic acid-beta-cyclodextrin@reduced graphene oxide (TiO2@ACD@RGO) composite photocatalyst was successfully synthesized by photochemical method and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform- infrared spectroscopy (FT-IR), Raman spectroscopy, Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). The photocatalytic degradation behavior of bisphenol A (BPA) was investigated under UV irradiation (lambda < 365 nm), the mechanism of photocatalytic degradation of BPA on TiO2@ACD@RGO was explained, and the stability and reusability of TiO2@ACD@RGO composite was also evaluated. The photocatalytic investigations showed that the TiO2@ACD@RGO possessed high photocatalytic efficiency for the degradation of BPA, which was better than that of TiO2 and TiO2@RGO. The reaction constant of TiO2@ACD@RGO for BPA was 0.739 mg/L.min, which was 1.34 times of TiO2@RGO and 1.87 times of TiO2, respectively. The predominant reactive oxygen species for BPA degradation was identified to be the O-2(-) and h(+). The high photocatalytic activity was attributed to the improvement of the electron transfer and mass transfer at the TiO2@ACD@RGO interface. Additionally, the TiO2@ACD@RGO presented excellent stability and reusability after five cycles.