The kinetics of removal of proteins adsorbed on a stainless steel surface by H 2O 2–electrolysis and factors affecting its performance

Abstract

The kinetics of the removal of β-lactoglobulin ( β-Lg) adsorbed on a stainless steel surface by H 2O 2–electrolysis treatment, in which hydroxyl radicals ( · OHs) generated by the electrolysis of hydrogen peroxide decompose the substances adhering on the surface, was investigated. The rate of removal of the adsorbed β-Lg from the stainless steel surface during the treatment was monitored in situ by ellipsometry. The dependencies of the removal rate on the H 2O 2 concentration, the electric potential applied to the surface, and the supporting electrolyte concentration were examined and the results were compared with those obtained for the treatment of a titanium surface. Differences in the removal rates of the protein from the stainless steel and titanium surfaces are discussed with respect to differences in the nature of the interaction between the protein and the surface. The atomic compositions of the stainless steel surface before and after treatment were analyzed by Auger electron spectroscopy, and the stainless steel surface was found not to be affected by the H 2O 2–electrolysis treatment. The influences of various coexisting materials on removal characteristics during the H 2O 2–electrolysis treatment were also investigated. The difference between the effect of coexisting substances on the decomposition rate for the radical reaction in the H 2O 2–electrolysis treatment and that for the well-known UV–H 2O 2 treatment in bulk solution is discussed.