Comparison With Composite Cathode And Study On Degradation Of Dye Waste Water With Two Cathodes In The Electro-fenton System

Acetylene black-PTFE cathode for electrogeneration of hydrogen peroxide（H₂O₂）,Fe²⁺ and H₂O₂ generate the hydroxyl radicals（?OH） which is non-selective very powerful oxidizing species. But the traditional Fenton methods show some limitations so we designed a solid catalyst containing iron species. The struction of Fe₃O₄ is octahedron,although the presence of structural ≡Fe（II） on the iron oxide surface, ≡Fe（II） formed in the conduction band through the ≡Fe（III） reduction rather than the structural ≡Fe（II） is the main species involved in the heterogeneous Fenton process. Preparation of composite Fe₃O₄-PTFE cathode, acetylene black cathode was used for electrogeneration H2O2 and the Fe₃O₄ cathode could initiate of the experiment.Reaction conditions were as follows: I took Fe₃O₄-PTFE electrode and acetylene black electrode connected in parallel as cathode, the other anode was Pt whose area was0.12cm2. Two centimeters distance between cathode and anode. I poured 200 mL acid fuchsine aqueous solution whose concentration was 50mg/L containing Na2SO4 solution of 0.05 M into reactor and kept air at 2L/min. The experimental results showed that:（1）H2O2 was electrogenerated, so the concentration of H₂O₂ could maintain an almost constant concentration in the heterogeneous Fenton process. It is convenient to treat of organic pollutants in water and wastewater, I also get the cost down.（2） After the degradation of acid fuchsine aqueous solution, the reactor had none ferric hydroxide sludge. It also solve the requirement of pH.（3） Compared with the single electrode, by means of Fe₂₊ ions added to the contaminated water, the novel E- Fenton process has more advantages.I designed several cathodes, for example, acetylene black-PTFE cathode with Fe₃O₄ cathode, acetylene black-PTFE cathode with MnFe₂O₄ cathode, acetylene black-PTFE cathode with Fe₂O₃ cathode, acetylene black-PTFE cathode with activated carbon cathode.The results showed that the degradation rate of acid fuchsine at absorption peak at 540 nm reached 95.8%, which is higher than other cathodes.Moreover, I used the acetylene black-PTFE cathode with Fe₃O₄ cathode to degradeacid fuchsine, the cell voltage were 3.0V,4.5V,6.0V,7.5V,9.0V,10.5V. When the cell voltage were 6.0V, the degradation rate of acid fuchsine reached 96.9%. The concentration of acid fuchsine were 20mg/L,35mg/L,50mg/L,65mg/L. As the concentration was 20mg/L,the degradation rate of acid fuchsine reached 99.7%. In addition, I degraded alizarin red S by the same way, the date was almost unanimous support for the results which showed that the novel E- Fenton process has high repeatability and no selectivity.