Continuous removal of trace bisphenol A from water by high efficacy TiO2 nanotube pillared graphene-based macrostructures in a photocatalytically fluidized bed

Abstract

The continuous removal of trace amounts of BPA from water is presently a challenging issue because of the low degradation constants at these low levels. In this study, TiO2 nanotubes (TNTs) pillared graphene-based macrostructures (TPGBM) were prepared by using TNTs as physical pillars. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analyses, and UV–vis-diffuse reflection spectrum (UV–vis-DRS) and photoluminescence spectrum (PL) data were used to characterize the TPGBM. A high BPA adsorption capacity was obtained by the TPGBM due to the higher specific surface area, more accessible π-π adsorption sites and more hydrogen bonding than that of GBM. The BPA occupied adsorption sites in TPGBM may be regenerated by photo-generated electrons induced O2− and OH. Both batch experiments and fluidized bed experiments indicated that the TPGBM had good adsorption–photocatalysis synergistic effects toward the decontamination of BPA. The TPGBM showed an outstanding removal performance toward trace BPA in aqueous solution, removing 86% of the BPA at an initial concentration of 0.05 mg/L in the continuous flow system under Xe lamp irradiation. Knowledge from this study provides important technical support and a theoretical basis for the continuous removal of trace environmental endocrine disruptors in water through the use of graphene-based composites.