The effects of different types of supporting electrolytes on the removal of beta-lactoglobulin (beta-Lg) after being adsorbed to a stainless steel surface by a H2O2-electrolysis treatment was investigated. In this process, hydroxyl radicals (center dot OH), generated by the electrolysis of hydrogen peroxide, decompose the substances adhering to the surface. The removal of the adsorbed protein from the stainless steel surface during the treatment was monitored in situ by ellipsometry. The apparent first-order removal rate constants, k(cl), for 17 types of supporting electrolytes were determined, as well as the current corresponding to the rate of generation of center dot OH. The kcl and generated current values for LiCl, NaCl, KCl, KNO3, K2SO4, CH3COOK, and K2CO3 were all similar. Ca2+ and Mg2+ strongly suppressed the removal of the adsorbed protein. The presence of ammonium compounds led to an increase in kcl and current values. In H2O2-electrolysis in the presence of potassium phosphate, the removal was extremely rapid, and an apparent increase in the thickness of the adsorbed layer was observed. The mechanisms responsible for the peculiar effects of calcium, magnesium, phosphate, and ammonium compounds were investigated by means of a Fourier transform infrared (FTIR) spectroscopic analysis, as well as by the characteristics of the removal under different treatment conditions.