Photoelectrocatalytic simultaneous removal of 17α-ethinylestradiol and E. coli using the anode of Ag and SnO2-Sb 3D-loaded TiO2 nanotube arrays.

Abstract Reclaimed water contains both residual contaminants and pathogenic microorganisms while their simultaneous removal has not been fully addressed. Thus, a photoelectrocatalytical system (PEC) was engineering herein using an innovatively synthesized composite of TiO2 nanotube arrays (TNTs) decorated with antimony doped tin oxide (SnO2-Sb) and silver nanoparticles (Ag) in three dimensions (TNTs-Ag/SnO2-Sb) to realize the simultaneous removal of 17α-ethinylestradiol (EE2) and Escherichia coli (E. coli). The optical and electrochemical properties of TNTs were improved after the loading of Ag and SnO2-Sb with an excellent the stability for reuse. A 68% removal of EE2 and more than 5-log removal of E. coli were achieved in 1 h in PEC. The DNA activity of E. coli was nearly completely lost after PEC treatment and the cytotoxicity of PEC treated EE2 solution was significantly reduced. Reactive species (HO and H2O2) and degradation products of EE2 were identified, and the transformation pathways were proposed accordingly. This study generates valuable information of the transformation kinetics and mechanism for simultaneous removal of EE2 and E coli. It also provides an effective and innovative technology for water reuse.