Electrochemical charge of silica surfaces at high ionic strength in narrow channels

We present a theoretical framework to calculate the electrochemical charge on silica surfaces in contact with high-ionic-strength solutions in narrow channels. Analytical results indicate that the contribution of the adsorbed metal cations to the total surface charge is not negligible when the salinity is larger than 1 mM. The electrical triple-layer model is proved much better than other models for high ionic strength. The charge regulation caused by the double-layer overlap in narrow channels will reduce the surface charge density but increase the zeta potential on silica surfaces.

Electrical potential and charge distribution near solid surfaces in the electrical triple-layer model. The symbol M represents the metal cations and A the anions.Figure optionsDownload high-quality image (62 K)Download as PowerPoint slide