On the application of nanostructured electrodes prepared by Ti/TiO2/WO3 “template”: A case study of removing toxicity of indigo using visible irradiation

New assays with HepG2 cells indicate that Indigo Carmine (IC), a dye that is widely used as additive in many food and pharmaceutical industries exhibited cytotoxic effects. This work describes the development of a bicomponent nanostructured Ti/TiO2/WO3 electrode prepared by “template” method and investigates its efficiency in a photoelectrocatalytic method by using visible light irradiation and applied potential of 1 V. After 2 h of treatment there are reduction of 97% discoloration, 62% of mineralization and formation of three byproducts assigned as: 2-amine-5-sulfo-benzoic acid, 2,3-dioxo-14-indole-5-sulfonic acid, and 2-amino-α-oxo-5-sulfo-benzeneacetic acid were identified by HPLC-MS/MS. But, cytotoxicity was completely removed after 120 min of treatment.

► IC exhibits genotoxic effects on HepG2 cells and is no harmful after treatment.
► Nanostrucutured Ti/TiO2/WO3 electrode are easily prepared by template.
► Cytotoxicity is negligible after treatment with visible light and potential of 1 V.