Effective visible-light-driven photocatalytic degradation of 17α-ethynylestradiol by crosslinked CdS nano-rod/TiO2 (B) nano-belt composite

New CdS nano-rod/TiO2 (B) nano-belt composites (denoted as CdS-NR/TiO2 (B)-NB) were successfully prepared via a two-step hydrothermal process. The chemical composition and structure of synthesized materials were characterized by X-ray diffraction (XRD), field emission scanning microscopy (FESEM), transmission electron microscopy (TEM), element map, UV visible diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence spectroscopy (PL). The prepared samples were used to remove 17 alpha-ethynylestradiol (EE2) under visible light irradiation, which has most potent estrogenic activity and resists to biodegradation. The results show that the B-type TiO2 (TiO2(B)) nano-belts are crosslinked with CdS nano-rods to form heterojunction with higher removal rate (92.00%) than pure CdS nanorods (55.67%) for 3 mg/L EE2 within 120 min when the mass ratio of CdS nanorods to TiO2 (B) nanobelts is 1:15. The degradation rate constant of EE2 over CdS-NR/TiO2 (B)-NB (0.001763 min(-1)) is 3 times higher than pure CdS-NR (0.00567 min(-1)) under visible light irradiation. Charge generation, migration and possible photocatalytic mechanism of EE2 on CdS-NR/TiO2 (B)-NB photocatalyst has been proposed based on the theoretical calculation and reactive species trapping experimental results. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.