Factors Affecting Performance of Cleaning Technique for Metal Surfaces Based on Electrolysis of Hydrogen Peroxide, H₂O₂-electrolysis

We have developed a novel technique for removing organic soilings from metal surfaces using hydroxy radicals (·OH). In the cleaning system, a metal surface fouled with organic soilings is made to contact with an aqueous solution containing hydrogen peroxide and supporting electrolyte. A slightly negative potential is then applied into the metal. The ·OHs, which are generated by the electrolysis of hydrogen peroxide (H₂O₂+e^--ē·OH+OH”) on the metal surface, effectively attack and subsequently remove the adsorbed organic soils. In this study, the removal behavior of model organic soilings (protein) during the H₂O₂-electrolysis cleaning using different types and concentrations of supporting electrolyte was investigated. The presence of ammonium compounds and potassium phosphate led to marked increase in the removal rate. The influences of the types of metal substrate and adsorbed material on the removal behavior were also investigated, which suggested that the adsorption state of organic soiling on a metal surface strongly affect the removal characteristics. Furthermore, the removal rates in the presence of various organic coexisting materials were investigated. It was found that the removal rate constant was only slightly lowered in many cases.