NaOCl水溶液に繰り返し浸漬された無酸素銅の抗菌性能に及ぼす防錆剤添加の影響

<p>Copper is known as antibacterial metallic material. Introducing such copper into frequently hand–touched places has been considered to reduce risks of outbreaks of illnesses caused by pathogens on environmental surfaces. When copper is used in environmental surfaces, surfaces of copper are exposed to the surrounding environment and become contaminated by various substances in the surroundings. As surfaces contamination can reduce the antibacterial activity of copper, cleaning henceforth must be carried out periodically on the contaminated surface. However, due to the cleaning agents such as the ethanol aqueous solution (EtOH) and the sodium hypochlorite aqueous solution (NaOCl aq.) used for wipe–cleaning, copper surfaces may be corroded and the antibacterial activities may be lost. In this study, we carried out surface chemical analysis using x–ray photoelectron spectroscopy (XPS) and evaluate the antibacterial activities of copper submerged in cleaning agents. Also, in this study, the antibacterial activities of copper compounds formed on the copper surfaces submerged in cleaning agents were evaluated. Copper surfaces submerged in distilled water, EtOH and NaOCl aq. were corroded and the antibacterial activities decreased. Cu, Cu₂O, CuO, Cu(OH)₂ and CuCl₂ were present on the copper surfaces submerged in cleaning agents. The strength of the antibacterial activities was in the order Cu₂O, CuCl₂>CuO>Cu(OH)₂>CuCO₃. When benzotriazole as a rust inhibitor was added to NaOCl aq., the antibacterial activities of copper decreased. Other inhibitors, i.e. sodium hexametaphosphate, sodium molybdate dihydrate, trisodium phosphate, tolyltriazole and sodium tungstate dihydrate as a rust inhibitor, was used, NaOCl aq., the antibacterial activities of copper improved in comparison with NaOCl aq. without the inhibitors. In particular, the antibacterial activities of copper submerged in trisodium phosphate inoculated NaOCl aq. was almost equivalent to that of clean copper.</p>