Diffusion and release behavior of Ag⁺ in ion‐exchanged antibacterial glaze

Abstract

A potential method for manufacturing antibacterial ceramics can be the incorporation of Ag+ ions into the surface of ceramic glaze via Ag+↔Na+ ion exchange. The ion‐exchange process is usually modulated by the concentration of AgNO3 in the ion‐exchange medium, which, in turn, affects the antibacterial activity. Therefore, the present study investigated the diffusion behavior of Ag+ ions into the glaze at different concentrations (2–10 wt%) of AgNO3 in the ion exchange AgNO3–NaNO3 medium and their release behavior from the ion‐exchanged glaze. The antibacterial activity of the Ag+ ion‐exchanged glaze was also evaluated. As AgNO3 concentration in AgNO3–NaNO3 molten salt increased from 2 to 10 wt%, the diffusion coefficient of Ag+ ions in the molten salt increased from 1.49 × 1021 to 3.84 × 1045 cm2 s−1, and its Nernst distribution coefficient increased from 0.65 to 4.13. This led to the increased incorporation of Ag+ ions in the glaze, which was beneficial for the ion‐exchanged glaze to release Ag+ ions, with the concentration increasing from 0.03 to 0.10 μg mL−1 cm−2 in 24 h, and maintain leaching of the Ag+ ions for a long time to exert long‐term antibacterial activity.