A novel templated synthesis of C/N-doped beta-Bi2O3 nanosheets for synergistic rapid removal of 17 alpha-ethynylestradiol by adsorption and photocatalytic degradation

The C/N-doped beta-Bi2O3 nanosheets photocatalyst was successfully synthesized via a novel solvothermal-calcination method and applied for removing 17 alpha-ethynylestradiol (EE2). Poly (aniline-co-pyrrole) (PACP) was not only used as C and N resources, but also as template to enlarge specific surface area during the preparation process. The PACP templated precursor calcined at 300 degrees C and 350 degrees C for 2 h were denoted as DBO-300 and DBO-350, respectively. The physical and chemical properties of as-prepared samples were characterized by element analysis, XRD, TEM, BET, XPS and UV-vis DRS techniques. The N element mass ratios in DBO-300 and DBO-350 were 1.883 wt% and 0.913 wt%, respectively. While the C element mass ratio in DBO-300 and DBO-350 were 2.579 wt% and 0.512 wt%, respectively. The total removal ratio of EE2 over DBO-300 was 95.30% after only 2 min of visible-light irradiation. While the total removal ratio of EE2 over DBO-350 reached 98.86% after 20 min of visible-light irradiation. The reaction rate constant over DBO-300 and DBO-350 were 13.93, 5.68 times higher than BO-350 (pure beta-Bi2O3 without PACP template calcined at 350 degrees C) respectively. The adsorption ability for EE2 over DBO-300 and DBO-350 was attributed to the high specific surface area and the hydrophobic nature of carbon, and the good photocatalytic performance was attributed to the narrower band gap induced by C and N doping. The hydrophobic EE2 in water could be rapidly removed by adsorption and photocatalytic degradation on C/N-doped beta-Bi2O3 nanosheets synergistically.