Development of a TiO 2 modified optical fiber electrode and its incorporation into a photoelectrochemical reactor for wastewater treatment

Abstract

Electrochemical advanced oxidation processes (EAOPs) are used to chemically burn non biodegradable complex organic compounds that are present in polluted effluents. A common approach involves the use of TiO 2 semiconductor substrates as either photocatalytic or photoelectrocatalytic materials in reactors that produce a powerful oxidant (hydroxyl radical) that reacts with pollutant species. In this context, the purpose of this work is to develop a new TiO 2 based photoanode using an optic fiber support. The novel arrangement of a TiO 2 layer positioned on top of a surface modified optical fiber substrate, allowed the construction of a photoelectrochemical reactor that works on the basis of an internally illuminated approach. In this way, a semi-conductive optical fiber modified surface was prepared using 30 μm thickness SnO 2:Sb films on which the photoactive TiO 2 layer was electrophoretically deposited. UV light transmission experiments were conducted to evaluate the transmittance along the optical fiber covered with SnO 2:Sb and TiO 2 showing that 43% of UV light reached the optical fiber tip. With different illumination configurations (external or internal), it was possible to get an increase in the amount of photo-generated H 2O 2 close to 50% as compared to different types of TiO 2 films. Finally, the electro-Fenton photoelectrocatalytic Oxidation process studied in this work was able to achieve total color removal of Azo orange II dye (15 mg L −1) and a 57% removal of total organic carbon (TOC) within 60 min of degradation time.