Silver ion release from electrodes of nanotubes of TiO2 impregnated with Ag nanoparticles applied in photoelectrocatalytic disinfection

Self-organized TiO2 nanotubes arrays electrodes were impregnated with 0–16% of Ag nanoparticles (Ti/TiO2–Ag) using different procedures. The electrodes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and photocurrent vs potential curves. The best results were obtained by electrode prepared by photochemical reduction, after immersion in a solution AgNO3 0.05 M (pH 8). The monitoring of Ag+ lixiviation by anodic stripping voltammetry at glassy carbon electrode indicated that a maximum of 2.5 × 10−6 M is released in the first 40 min of treatment, but it is neglected when used subsequently. Moreover, the antimicrobial behavior of electrodes Ti/TiO2–Ag applied in photoelectrocatalysis presented 100% disinfection in 3 min by using UV irradiation and 99.6% in 30 min with visible irradiation. In addition, the analysis of silver in solution along the reaction shows a negligible lixiviation and a high stability of the surface silver deposits.