Photoelectrochemical degradation of acetaminophen and valacyclovir using nanoporous titanium dioxide

Electrochemically treated nanoporous TiO2 was employed as a novel electrode to assist in the photoelectrochemical degradation of acetaminophen and valacyclovir. The prepared electrode was characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Cyclic voltammetry (CV), Mott-Schottky plots, ultraviolet-visible light (UV-vis) absorbance spectroscopy, and a total organic carbon (TOC) analyzer were employed to investigate the photoelectrochemical degradation of acetaminophen and valacyclovir. The results indicated no obvious removal of acetaminophen and valacyclovir over 3 h when separate photochemical degradation and electrochemical oxidation were employed. In contrast, acetaminophen and valacyclovir were rapidly eliminated via photoelectrochemical degradation. In addition, electrochemically treated nanoporous TiO2 electrodes significantly enhanced the efficacy of the photoelectrochemical degradation of acetaminophen and valacyclovir, by 86.96% and 53.12%, respectively, when compared with untreated nanoporous TiO2 electrodes. This enhanced performance may have been attributed to the formation of Ti3+, Ti2+, and oxygen vacancies, as well as an improvement in conductivity during the electrochemical reduction process. The effect of temperature was further investigated, where the activation energy of the photoelectrochemical degradation of acetaminophen and valacyclovir was determined to be 9.62 and 18.42 kymol, respectively. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.