The preparation and characterization of a graphite–PTFE cathode system for the decolorization of C.I. Acid Red 2

An undivided electrochemical system was used to produce hydrogen peroxide on a graphite–polytetrafluoroethylene cathode. Key factors for cathode preparation, electrochemical activity as well as cathode stability were investigated. The current efficiency for hydrogen peroxide production was ∼61–78% over a wide pH range (3–11) which decayed insignificantly after 10 times reuse. The influence of Na2SO4, pH, cathodic potential, initial dye concentration and ferrous ion concentration on decolorization were systematically studied. The results show that the presence of ferrous ion improved color removal greatly; at 0.2 mM Fe2+ almost 80% of the dye could be removed after 20 min, indicating that the electro-Fenton process offers promise for dye removal.