Electro-photocatalytic fenton decolorization of orange g using mesoporous TiO₂/stainless steel mesh photo-electrode prepared by the sol-gel dip-coating method

A photo-electrochemical process is a powerful and eco-friendly method for treating industrial wastewater. Electro-photocatalytic Fenton (EPF) was employed for orange G decolorization using two kinds of photo-electrodes with TiO₂ film-coated stainless steel (SS) mesh. These photo-electrodes are prepared by a dip-coating method from the sol-gel-derived TiO₂ sols incorporating with various amounts of P25+TiO₂ powders (SGDC method). The single dip-coated electrode with the TiO₂ sol containing 50 g/L P25 powders possesses similar crystallinity and decolorization performance to the four repetitive dip-coated electrodes with pure TiO₂ sol. The kinetics of orange G decolorization using P25+TiO₂ film electrode in photocatalytic (PC), electro-Fenton (EF) and EPF processes followed pseudo first-order kinetics model, and the EPF has the highest reaction rate. The efficiency of orange G decolorization achieves 78% via the EPF reaction for 3 h. The SGDC method using the TiO₂ sol containing P25 powders not only enhances the TiO₂ coating on the SS substrate, but also produces microcracks in the film, that facilitates the in-situ generation of ferrous ions and further induces the EPF reaction for an effective degradation of organic matter in wastewater.